BIO 112 Module 4 Animal Evolution Ch. 27

Phylum Chordata

Fundamental Characteristics: notochord, dorsal nerve cord, pharyngeal pouches, postanal tail exist during lifetime or embryological development bilateral symmetry, segmentation, radial cleavage triploblastic deuterostomes notochord flexible, supportive, rodlike structure found along dorsal midline of all chordates during life pharyngeal pouches form in embryo as pockets of ectoderm - grow inward, fusing with pockets of endoderm lining pharynx

In Figure 27.10 the clade Deuterostomia is most closely related to which two main clades? see figure above

Lophotrochozoa and Ecdysozoa

Protostomes

Lophotrochozoa and Ecdysozoa

These primitive chordates retain all of the characteristics used in chordate classification through adulthood. They are the only chordates to do so. They are small blade-like critters that live embedded in the sea floor, where they feed on food particles adrift on the current.

Lancelets

Phylum Arthropoda

Largest animal phylum butterflies, fleas, centpedes, lobsters, barnacles, spiders, ticks, fossil trilobites no other phylum approaches the diversity or biomass of phylum Arthropoda adapted to habitats characteristics presence of chintinous exoskeleton both soft as in mosquito or hard in crabs tough exoskeleton provides support and protection for arthropods movement possible b/c exoskeleton divided into plates over body and cylinders around appendages to grow must undergo ecdysis or molting - intervals between molts termed instars bilateral symmetry 3 body regions - head, thorax, abdomen spiders and shrimp have cephalothorax and abdomen others head and trunk exhibit segmentation or metamerism - each somite pair of jointed appendages segments may fuse - forming functional groups called tagmata - functions vary - locomotion, food gathering, copulation, gas exchange, egg brooding great degree cephalizaiton sense organs - compound eyes, antennae touch, smell, hearing, balance, chemical reception well developed coelomates, coelom reduced to portions of reproductive and excretory systems major body cavity hemocoel blood-filled spaces w/in tissues digestive system complete - foregut,midgut,hindgut osmoregulation occurs i Malpighian tubules and glands respiration through gills, tracheae, book lungs, body surface - efficient trachae air tubes bring oxygen directly to tissues, cells blood enters through ostia, open circulatory system heart pulsate vessel along dorsal midline dioecious, undergo internal fertilization females oviparous egglaying metamorphic changes - larval form different from adult

Phylum Arthropoda, Subphylum Hexapoda

1/3 animals members of this subphylum 2 Classes - Entognatha - order Collembolla (springtails) class - Insecta (ants, moths, fleas,etc.) 6 pairs of uniramous legs 3 tagmata - head, thorax, abdomen study of insects - entomology Class Insecta most diverse, abundant of all arthropods largest group of animals +one million differ from other arthropods by having 3 pairs of legs, 2 pairs of wings in thoracic region tagmata include head, thorax, abdomen cuticle of each segment made of 4 plates, sclerites, connected by hinge joint heads pair of large compound eyes 3 ocelli, 2 antennae divided into prothorax, mesothorax, metathorax each with pair legs most mesothorax and metathorax have pair of wings abdomen: 9-11 segments with end having external sex organs digestive - foregut (mouth, salivary gland, esophagus, crop, gizzard) midgut (stomach, gastric caeca) hindgut (intestine, rectum, anus) feeding: predaceous (praying mantis) phytophagous (grasshopper) saprophagous (dung beetles) parasitic (fleas) tubular heart in pericardial cavity pumps hemolymph through dorsal aorta tracheal system efficient respiratory apparatus used for breathing air spiders unique excretory system with Malpighian tubules operate in conjunction with specialized glands in wall of rectum for excretion nervous system similar to crustaceans keen sense organs microscopic in body wall sensilla for auditory receptioin grasshoppers have tympanic organs in their legs chemoreception with chemoreceptors located on mouth parts, may appear on antennae (ants, bees) or legs (butterflies and moths) eyes - 2 plans: simple eyes in larvae, nymphs, some adults compound eyes in majority which aids to see simultaneously all directions complex behavior and communication skills dioecious many with internal fertilization oviparous egg laying, some viviparous (live-bearing) some females have ovipositor lays eggs stinger is modified ovipositor associated with venom glands hatching young resemble adult incomplete, gradual metamophosis, young resemble adults but smaller complete metamorphosis, larvae different from adult different food requirements 88% insects undergo complete metamorphosis with 3 stages: larva, pupa, adult +30 orders

What is an animal?

Animals are eukaryotic multicellular heterotrophs

Birds evolved from a lineage of small, two-legged dinosaurs called theropods. The oldest bird fossil is thought to be about 150 million years old. It is called...

Archaeopteryx

4 living Orders of Reptiles

Chelonia - turtles, tortoises Sequamata - lizards, snakes, amphisbaenians Sphenodonta - tuataras Crocodilia - alligators, crocodiles

4 Classes Myriapods

Chilopoda - centipedes Diplopoda - millipedes Symphyla - soft-bodied myriapodes Pauropoda - soft-bodied myriapodes

pinworms

Enterobius vermicularis most common intestinal parasite in US night, female migrates to anal opening lays eggs parents put tape over anus bedtime to capture pinworms to diagnose eggs contaminate bedding clothing easily spread

Schistosoma is a parasitic worm of the phylum...

Platyhelminthes

This structure is the opening to the water vascular system in starfish. The madreporite The spiracle The spicule The maculite

The madreporite

trichinosis

Trichinella spiralis Trichinella small nematode parasite in humans when host eats muscle containing encysted juvenil parsites - infected pork

Acoelomates are characterized by

a solid body without a cavity surrounding internal organs.

Order Crocodilia

alligators, caimans, birds only living descendants of archosaurian lineages (group includes now-extinct dinosaurs) elongated heavy skull with robust mandible,maxilla housing large teeth in bony sockets secondary bony palate in mouths allows breathe air when partially submerged and mouth full of water 4 chambered heart, complete digestive, well developed nervous system excellent vision with color vision light-reflectng layer - tapetum behind retina increases ability to see at night - tapetum responsible for eyes "glowing" at night nictitating membranes cover eys when animal underwater sensory pits line jaws of crocs serve lateral line system oviparous, some show parental care

endothermic

animal like birds capable of maintaining body temperature through metabolic activity

ectothermic

animal like reptile absorb external heat as their main source of body heat

invertebrate

animals that lack a backbone

vertebrates

animals with a backbone

Bilateria

animals with bilatral symmetry

Radiata

animals with radial symmetry

Subclass Cirripedia

barnacles Charles Darwin studied 2 larval stages - nauplius larvae single median eye and free-swimming cyprid larvae attach to substrate headfirst and develop into juvenile barnacles adults are sessile with some attached to substrate by stalk - gooseneck barnacle or cemented to substrate -bay barnacle most enclosed in calcareous plates no abdomen and reduced head when feeding, top plates open and feathery cirri filter food from water some parasitic on crabs can slow ship down if growing on it fouling organisms have to be removed periodically

Symmetry

basic feature of animal bodies or absence of symmetry

Class Osteichthyes

bony fishes - largest most diverse of chordate 2 Subclasses: Subclass Sarcopterygii or lobe-finned fishes - fossil species and extant coelocanth Subclass Actinopterygii - ray finned fishes - 95% of vertebrate species goldfish, catfish, gars, tuna, seahorses, pufferfish, swordfish, trout ray-finned fishes b/c fins consist of webs of skin supported by bony spines paired pectoral and pelvic fins and skin with mucous glands embedded with dermal scales 3 types of scales: *ganoid scales- flat, heavy silvery ganoin top and bone bottom, shaped like arrowhead = gars *cycloid scales - thinner, flexible overlap each other, growth rings, bony fish -carp, salmon *ctenoid scales - comblike ridges on exposed edge - bass , sunfish most bony fishes have fusiform (torpedo shape) body tapered both ends segmentation of muscles in zigzag myomeres respiration actinopterygians occurs in gills, covered protective flap, operculum swim bladder serves as flotation device 2 chambered heart - closed circulatory system ectotherms - control body heat through external sources complete digestive with pancreas and liver kidney filter wastes in blood freshwater fish well developed kidneys, salt water fish poorly developed nervous system well developed - brain, small cerebrum, olfactory lobes, large cerebellum, optic lobes senses: eye, sound inner ear, olfaction smell, lateral line system detect vibrations dioecious and oviparous

Class Cubozoa

box jellyfishes medusoid form prominent polyp inconscicuous pedalia - corners of umbrella venom cardiotoxic, neurotoxic, dermatonecrotic

Class Ophiuroidea

brittle stars or basket stars arms slender sharply set off from central disk ambulacral grooves covered with ossicles do not possess pedicellariae tube feet have no suckers madreporite (sieve plate that connects internal water vascular system to exterior) is located on oral surface 5 movable plates serve as jaws around mouth of brittle stars no intestine or anus visceral organs confined to central disk

Spiders, scorpions, ticks and mites belong to the subphylum

chelicerata

Class Polyplacophora

chitons bottom-dwelling marine molluscs shell covers dorsal side with 8 plates elongated and flattened body beautiful ornate shells

Sharks, and rays belong to the class

chondrichthyes

Squid and Octupuses are able to change color rapidly with the assistance of cells within the epidermal layer that are called....

chromatophores

Squid and Octupuses are able to change color rapidly with the assitance of cells within the epidermal layer that are called.... chromatophores luciferophores colorophores none of these are correct

chromatophores

Lophotrochozoans

clade consisting phyla Platyhelminthes (flatworms) Rotifera (rotifers) Mollusca (snails, oysters, and squid) Annelida (segmented worms) Acanthocephala (thorny-headed worms) Gastroticha (spiny aquatic organisms) Bryozoa (moss animals) Entoprocta (entoprocts) Brachiopoda (lampshells) Nemertea (ribbon worms)

3 classes urochordates

class Ascidiacea - tunicates class Thaliacea - salps class Appendicularia - larvaceans enclosed in nonliving tunic made of protein and tunicin tunicates, sea squirts take in water through incurrent siphon, filter water for food, eliminate water and wastes through excurrent siphon digestive system complete circulatory system - heart and 2 large vessels nervous sytem underdeveloped monoecious - single ovary, testis larvae free-swimming - resemble tadpole

Class Aves

dinosaurs are now the birds 9700 extant species of class Aves, birds described 2 superorders: Superorder Paleognathae - flightless birds (ratites) ostrich - no keel on sternum makes flight impossible Superorder Neognathae 27 orders of modern birds - do have keeled sternum some flightless bipedal, oviparous, endothermic, winged tetrapods characteristic most distinguishable: presence of feathers, specific arrangment and appearance of feathers - plumage and can vary within species respect to age and sex feathers arranged on body specific tracts or pterylae Types of feathers: Contour feathers provide shape, aid flight Down feathers insulate Natal down feathers - ducklins or chick fluffy Filoplumes simple, hairlike feathers provide Sensory feedback on contour feather activity Bristles - sensory and protective feathers found near mouth of some - like flycatchers feathers constant maintenance - birds preen or groom daily apply oily substances from uropygial gland located near base of tail for waterproofing and discourage microbial growth contour feather - smooth, nonpigmented base extending beneath skin called calamus (quill) Inferior umbilicus at base of calamus appears a small hole shaft above skin is rachis vane is flat structure each side of feather with filaments called barbs bars consists of barbules connected by hooklets sturdy skeleton - bones have air cavities make lightweight flight possible vertebrae fused with exception of neck (cervical) vertebrae tail or caudal vertebrae fused forming pygostyle sturdy pelvic girdle allows birds to walk and perch in many, sternum is keeled, allowing for attachmen of flight muscles "wishbone" or furccula of bird consists of fused clavicles that allow for flight skulls highly fused feature large orbits for eyes single occipital condyle ring of bones called sclerotic bones encircles supports eyes flight muscles massive in birds of flight talons or claws such as eagle - great force 4 chambered heart metabolism and heart rate heightened chicken - resting heartrate 250 bpm active hummingbird more than 1200 bpm advanced immune system respiratory system complex air inhaled system of 9 air sacs in thorax and abdomen air sacs with lungs keep bird supplied with air to fuel oxygen requirements syrinx located where trachea forks in lungs allows birds to produce myriad sounds keratinized, toothless beaks specialized for diets complete digestive crop enlargement of esophagus serves as storage chamber stomach 2 compartments: proventriculus - secretes gastric juices help chemically break down food and gizzard holds pebbles that help break down of food via grinding both crucial for digestion b/c birds have no teeth solid wastes, urine, reproductive cells exit body by cloaca excrete nitrogenous wastes as uric acid crystals marine birds have salt glands above each eye to eliminate excess salt well developed nervous system 3 major portions of brain: cerebrum = controls complex behavior patterns, migration, navigation, mating behavior, nest building cerebellum - controls muscular coordination and flight-related matters large optic lobes responsible for acute vision and association good color vision and excellent monocular and binocular vision nictitating membrane lubricates and protects the eye exception of flightless birds, waterfowl, others, senses of smell and taste poorly developed hearing like vision highly developed oviparous males testes active only during breeding season lack penis females only left ovary and oviduct develop to reproduce birds must bring cloacal surfaces togehter fertilization occurs in upper region of oviduct before albumen (egg white) and shell are added to egg eggs usually laid in nest and incubated by one or both parents upon hatching, chicks and ducklings precocial - ready to run or swim others - mockingbird and canary altricial (helpless) require parental care for period of time

Flies and mosquitos belong to the class diptera chelicerata chondrichthyes odonata

diptera

Class Gastropoda

diverse class marine, freshwater, terrestrial have shell one-piece univalve slugs no shell end of shell - apex as grows, successive whorls increase in size central axis - columnella opening of shell aperture protective operculum covers aperture cephalic regions well developed head with 2 tentacles with eye at end each use foot for locomotion monoecious and dioecious eggs enclosed in egg cases found by beachcombers

Class Oligochaeta

earthworm or night crawler burrows in moist, rich soil emerges at night during dry weather, can burrow several feet below surface become dormant wet weather, stay near surface, anus or mouth protruding through the burrow when disturbed too much water, certain stimuli, vibrations or chemicals, emerge from burrow prostomium on anterior end and pygostyle on posterior end in most earthworms, each segment 4 pairs of setae from small pores in cuticle to outside feed decayed organic material, plant material, refuse, animal matter food enters mouth, after leaving esophagus, stored in crop crop to gizzard, ground into pieces digestion absorption in intestine waste through anus pair of metanephridia for excretion no respiratory organs gas exchange surface moist skin closed circulatory system, 4 pairs aortic arches nervous system CNS and peripheral nerves - brain, ventral nerve cord floor of coelom to last somite monoecious with male/female same body, no self-fertilization swelling clitellum seen on segments behind genital pores genital setae - clitellum secretes mucus holds mating earthworms together copulation reciprocal transfer sperm 3 hours few days after copulation, clitellum secretes dense mucus form cocoon eggs from female gonopores and sperm seminal receptacles collected en route fertilization occurs w/in cocoon 2-3 weeks

Phylum Annelida

earthworm or night crawler leeches, tubiflex, worms, sandworms, parchment worms, bloodworms coelomates bilateral symmetry annuli - grooves dividing each segment each segment is metamere or a somite repeated pattern of metameres metamerism segments internally delimited by structures called septa annelids with exception of leeches, possess tiny bristles setae on somites that vary in size, form, function different species some setae i.e.. earthworms serve as anchor mechanisms other setae used in locomotion and respiration two-part head prostomium - front of mouth liplike extension over dorsal portion mouth and peristomium- contains the mouth each segment typically contains coelom and nervous, respiratory, circulatory and excretory structures with exception of leeches, coelom filled with fluids, giving animal hydrostatic skeleton outer layer of annelids consists of protective cuticle extensive muscle systems circular and longitudinal locomotion and peristalsis movement food cutaneous respiration, 5 pairs of pumping vessels are hearts blood contains transport protein hemoglonin excretory system pair nephridia removes waste from each segment from external pores

triploblastic

earthworms, beetles, snakes, eagles 3 germ layers - ectoderm, mesoderm, endoderm

segmented animals

earthworms, insects, vertebrates body parts repeated along length of animal's body

Starfish, sand dollars, and sea urchins belong to the phylum crustacea echinodermata chelicerata mollusca

echinodermata

Class Branchiopoda

fairy shrimp, brine shrimp no carapace Brine shrimp sold as Sea Monkeys eggs are metabolically inactive in state of cryptobiosis when purchased when placed in salt water, they hatch forming larvae called nauplii - mature into sea monkeys best-known - water flea - Daphnia spp. found in ponds

filter feeders

filter out food particles suspended in the surrounding water as they draw the water through their body

Phylum Platyhelminthes

flatworms planarians, flukes, tapeworms free-living found terrestrial, freshwater, marine bilaterally symmetrical, tripoblastic acoelomates many monoecious but practice cross fertilization lack specialized respiratory and circulatory systems exchange gases through diffusion

acoelomates

flatworms (tapeworms) don't have a coelom between digestive system and outer body wall

Class Anthozoa

flower animals polyps only colonial or solitary sea anemones, sea fans, sea pens, sea pansies, corals

germ layers (tissues)

form various tissues and organs of the body

Class Crinoidea

fossil species, sea lilies, feather stars oceans in Cambrian period oral region faces upward resembles upside down starfish with opposiste side attached to stalk attaches to substrate with lower portion - holdfast body of crinoid - calyx covered by leathery temen with 5 arms of feathery pinnules - arms and calyx are crown sessile species have stalk of ring-shaped ossicles and branches called cirri

Subclass Copepoda

freshwater and marine may have largest animal biomass on earth early scientists referred to them copepods as cyclops have single compound median eye in adult form lack a carapace antennules may be longer than appendages major component of zooplankton, important in food chain several are parasites on invertebrates, fishes, sharks, marine mammals

Class Amphibia

frogs, toads, salamanders, amphiumas, sirens, newts, caecilians evolved from sarcopterygian fishes during Devonian period to venture from water and colonize land - developed protective integument - breathe in terrestrial environment specialized limbs remain dependent on water to lay eggs bony skeletons with vertebrae, gills during development, moist, glandular integument w/ external scales, some species use integument take air in through skin - cutaneous respiration pigment cells - chromatophores in skin responsible for color large mouth, small teeth, 2 internal nares or nostrils some psosess protrusible muscular tongue to mouth closed circulatory 3 chamber heart, 2 atria, 1 ventricle elminate nitrogenous waste urea well developed nervous - brain - fore,mid,hind brain eyelid nictitating membrane tympanic membrane for hearing dioecious frogs, toads external fertilization salamanders internal fertilization oviparous eggs are mesolecithal - have large yolk, jellylike membranes larval forms - tadpoles -aquatic with gills salamanders neotenic = retain gills in adults

Among the characteristics unique to animals is

gastrulation.

Eutherians

give live birth

Eutherians lay eggs give live birth have a pouch for young lay eggs and produce milk

give live birth

Class Hirudinea

leeches freshwater habitats monoecious, obvious clitellum only in breeding season head reduced, no setae, no internal septa not all bloodsuckers 25% are predaceous, feed on oligochaetes, snails, insect larvae 75% leeches are ectoparasites on invertebrates and vertebrates blood-sucking leeches produce salivary secretions that contain anesthetic, anticoagulants (hirudin) and a vasodilator many species of leeches can consume up to 11 times their weight in blood in a single 40 minute feeding period used to remove blood in medical procedures after water is removed from blood digestive process may take up to 6 months

Hox genes

influence the embryological patterning of the body plan, body axis and arrangement of body parts

endoderm

innermost germ layer, gives rise to the lining of the digestive tract (or cavity) and organs such as the liver and lungs of vertebrates Cnidarians only have first two germ layers

diploplastic

jellyfish two germ layers - ectoderm and endo derm

In the Phylum Mollusca this structure secretes the shell. mantle coelom radula foot

mantle

Class Turbellaria

marine most are carnivores movement food diffusion no anus, incomplete digestion gas exchange surface of body flattened body increases surface area increase rate efficiency gas exchange many reproduce asexually through fission monoecious, but capable of sexual reproduction hermaphroditic don't exhibit self-fertilization but by mutual fertilization - cocoons laid in jellylike masses regenerative powers best known one is planarian - freshwater feeds on other invertebrates

Eumetazoans Radiata

marine invertebrates sea anemones, jelyfishes, Porteguese Man-O-War coral, Hydra (freshwater)

Phylum Chordata, Subphylum Urochordata

marine tunicates, salps, ascidians, larvaceans bright colored bags jelly attached to marine substrate filter water for food don't resemble typical chordates adults possess gill slits and larval form presence other traits of chordates

Class Mammalia

marine, freshwater, aerial, terrestrial 5000 species mammals 26 orders montremes or prototherians - 1 order - marsupials or metatherians - 7 orders placentals or eutherians - 18 orders Monotremes - egg laying mammals oviparous duck-billed platypus and echina vestiges of ancient group marsupials have marsupium or pouch - pregnant females develop a modified yolk sac in womb that provides embryo nutrients and give birth at early stage of embryological development after birth, newborn marsupial crawls to pouch and attaches itself to nipple for nourishment appeared 120 million years ago Placental mammals appeared next - now the majority - embryo remains in uterus receiving nutrients and oxygen from mother extended time - placenta serves as interface between embryo and mother - young are born altricial (kittens, mice) or precocial (calves, dolphins) most obvious characteristic is HAIR - provides insulation and protection, camouflage or warning, give sensory feedback coat of mammal - pelage Vibrissae or whiskers long coarse hairs used in gathering tactile information glands in integument - sweat glands, scent glands, sebaceous oil glands - mammary glands endothermic, maintain own body temperature 4 chambered heart respiratory system driven by muscular diaphragm carnivorous, herbivorous, omnivorous with specific modifications to digestive system diverse dentition based on diet - toothless anteaters, conical fish-eating homodont teeth of dolphins most exhibit number tooth types (heterodont) including incisors, canines, premolars, and molars lower jaw is single bone middle ear has 3 ossicles (bones) stapes (stirrup) incus (anvil) malleus (hammer) with few exceptions, mammals have 7 cervical (neck) vertebrae nervous system well developed large cerebrum responsible for majority complex behaviors and learning senses developed in various mammals depending on role in nature special sense of echolocation extremely well developed in bats and dolphins

Origin and Radiation of Amniotes

most recent common ancestor living amphibians and amniotes lived 350 million yrs ago. fossils found earliest amniotes appear lived warm moist environments as earlier tetrapods new environments expanded dry and hig latitude regions earliest resembled small lizards w/ sharp teeth - sign they were predators included herbivores, evidenced by grinding teeth, etc. include today 2 clades of terrestrial vertebrates: reptiles and mammals

Dragonflies and damselflies belong to the order

odonata

Dragonflies and damselflies belong to the order porifera diptera odonata cephalopoda

odonata

Phylum Echinodermata

organisms with pentamerous (5 pointed) radial symmetry body wall ndoskeleton sall, calcareous ossicles include surface spines with jaw-like pincers or pedicellariae discourage barnacles or other fouling organisms from attaching to their surffaces sea urchins - poison glands water vascular system of canals & appendages function in locomotion, feeding, sensory reception, gas exchange tube feet of starfish powered by this hydraulic system adults lack head, brain and segmentation digestive system complete circulatory system reduced, radiates in 5 directions, circulating colorless blood gills protrude from coelom for respiration in some sea cucumbers use cloacal structures, cloacal trees for respiration nervous system nerves in ring around mouth radially outward from inside body no excretory organs starfish great regenerative powers purposely detach limb to escape predator - autotomy dioecious - after fertilization - zygote becomes bilaterally symmetrical ciliated larva or bipinnaria passes through several stages before radially symmetrical adult

eumetazoa

other

Phylum Rotifera

primarily freshwater study to gain better understanding of evolution, diversity, regeneration, ecology, behavior but not good commercially or medically wheel animalcules crown of cilia on heads in motion spinning wheel pseudocoelomates consume small invertebrates and are eaten by other animals lack circulatory system complete digestive system respire through body surface bilobed brain sends paired nerves to organs dioecious female larger than male stay in state of biological activity arrested state cryptobiosis for 4 years

All chordates share these characteristics sometime during their life time. Most of these are present only during the embryonic stages.

pharyngeal slits, hollow dorsal nerve chord, stiff notochord, and post-anal tail

Humans Homo sapiens

primates nested within group informally called apes stand upright, bipedal (walk on 2 legs) larger brain capable of language, symbolic thought, artistic expression, use of complex tools

Sponges

phylum Porifera monophyletic some suggest paraphyletic sedentary mistaken for plants by ancient Greeks most species marine size few mm to few meters filter feeders represent lineage that originates near the root of phylogenetic tree of animals, *basal animals* lack tissues interior of body lined with flagellated choanocytes mobile cells called amoebocytes

Class Hydrozoa

polyp form dominant most are marine with some freshwater Hydra, Man-O-War (US East Coast - half million stings) asexual polyp and sexual medusa stage

Sponges belong to the phylum

porifera

jellyfish, tapeworms, flukes

saclike body incomplete digestive tract - in mouth , out mouth

These chelicerates glow under UV light, so scientists often search the deserts at night with UV lights to find them for research projects. These creatures are... ticks mites spiders scorpions

scorpions

Order scorpiones

scorpions painful sting venomous sting potent to kill human some have fluorescent chemical in cuticle when exposed to black light most consume insects secretive nocturnal, living as ambush hunters, stalkers

Chondrichthyans

sharks, rays biggest most successful vertebrate predators in oceans clade Chondrichthyans "cartilage fish" skeleton composed predominantly of cartilage, impregnated with calcium 1,000 species living threatened with overfishing

Phylum Porifera

sponge pore bearer majority are sessile larval are free-swimming skeletal structure - spicules - siliceous crystalline spongin - collagenour protein

parazoa

sponges

Class Asteroidea

starfish, sea stars bodies gradually drawn out into 5 arms (rays) radiating from central disk some have 6 or more arms body appears flattened covered by thin epidermis may have calcareous spines dioecious fertilization external regeneration common fertilized eggs develop into planktonic bipinnaria larvae with some into brachiolaria (armlike structures) larvae larvae are bilaterally symmetrical, adults are radially symmetrical aboral dorsal surface smooth, granular or covered with spines mouth located on oral ventral side ambulacral groove found in the center of this area bordered by tube feet or podia near base of spines groups pedicellariae (pincer like) used to fee surface of debris coelomic cavity or papulae cover epidermis function in gas exchange or excretion madreporite (external opening of water vascular system) seen on side of central disk - responsible for movement, food gathering, respiration and excretion

Deuterostomes

starfish, sharks, frogs, birds, humans All triploblastic coelomates undergo radial cleavage and during embrological development, blastopore forms anal opening

Class Maxillopoda

subclasses copepods and barnacles most have 5 cephalic segments, 6 thoracic segments, 4 abdominal segments, and a telson

Class Cestoda

tapeworms endoparasites of humans and other vertebrates most require two hosts usually present in digestive tract of final vertebrate host reach lengths of more than 10 m totally dependent on host for nutrition b/c lack digestive tract tegument permits nutrients to enter body while protecting body against alkaline substances and digestive enzymes in host anterior region scolex contains hooks and suckrs for attachment hooks encircle crown rostellum behind scolex is subunits proglottids strobila main mass of tapeworm, composed of proglottids

Class Malacostraca

terrestrial, freshwater, marine 3 tagmata, head with 5 segments, thorax with 8 segments, abdomen with 6 segments members are diverse and presently going under reorganization Order Decapoda - most familiar crustaceans - true shrimp, prawns, hermit crabs, fiddler crabs, snow crabs, blue crabs, lobsters, crayfish 18,000 species described 10 legs anterior 3 pairs legs - mouthparts called maxillipeds many have 1 pair walking legs - enlarged pincers called chelae or claws additional appendages of cephalothorax, the pereopods, used for walking each abdominal segment pair biramous appendages swimmerets or pleopods final pair abdominal appendages, uropods form part of telson (terminal segment of crustacean abdomen)

2 defining characteristics Liphotrochozoa

presence of horse-shoe shaped crown of ciliated tentacles (lophophores) minute, translucent top-shaped ciliated larvae (trophophores)

Which of the following was probably the least important factor in bringing about the Cambrian explosion?

the movement of animals onto land

Which of these is a point of conflict between the phylogenetic analyses presented in Figures 32.10 and 32.11?

the relationship of taxa of segmented animals to taxa of nonsegmented animals

Amphibian is a Latin term that means "two-lived". Please select the answer that best describes the reason they are two-lived. none of these they are ectothermic they undergo metamorphosis they must keep their skin moist so they must live near the water so they have both water and

they undergo metamorphosis

filarial worms

young called microfilariae humans - filarial worm Wuchereria bancrofti infects people in tropical countries Africa, South America females live in lymphatic system release microfilaeiae into lymphatic system and blood mosquito bites infected person and is vector to spread disease responsible disfiguring disease elephantiasis most common filarial disease in US is heartworm in dogs, caused by Dirofilaria immitis deadly to dogs if untreated mosquitoes vector for heartworms vinegar eels free-living nematodes found in fermented fruit juices and unpasteurized vinegar Turbatrix actively feed upon bacteria in liquids vinegar in kitchen is pasteurized

Reflected in current hypothesis of animal phylogeny

1. All animals share a common ancestor - monophyletic, forming clade Metazoa, all extant and extinct descended from common ancestor 2. Sponges are basal animals - extant taxa, sponges (phylum Porifera) branch from base of animal tree 3. Eumetazoa is clade of animals with true tissues - all animals clade of eumetazoans ("true animals") true tissues evolved in common ancestor of living eumetazoans - some such as ctenophores and cnidarians have 2 germ layers and radial symmetry 4. Most animal phyla belong to the clade Bilateria. Bilateral symmetry and the presence of 3 germ layers are shared derived characters help define clade Bilateria. Contains majority of animal phyla - members known as bilaterians Cambrian explosion rapid diversification of bilaterians 5. Most animals are invertebrates - lack a backbone. Only one animal phylum Chordata includes vertebrates - animals with backbone

Phylum Arthropoda, Subphylum Myriapoda

13,000 species centipedes, millipedes, relatives all terrestrial myriapods possess 1 pair antennae, pair simple eyes breathe through spiracles connected to tracheal system Malpighian tubules sites of excretion in myriapods brain poorly developed females lay eggs hatch into young resemble adults but fewer segments and legs hundred-legger - centipede class Chilopoda - most have 30 pairs legs centipedes - one pair legs per segment flattened, elongate arthropods chitinous exoskeleton, carnivorous venom claws on first pair legs, capture kill prey dioecious poisonous bite some i.e. poisonous black centipede of N. America, most beneficial in gardens milllipedes - class Diplopoda - thousand leggers 10,000 species identified herbivorous or detritivorous roll into ball when disturbed and emit foul-smelling odor from repugnatorial glands dome-shaped body 25 to more than 100 segments 2 pairs legs per segment with exception of anterior and posterior segments reproduce sexually, larval forms may be mistaken for centipedes have one pair of legs per segment

Order Chelonia

300 species turtles, tortoises most turtles aquatic, terrestrial and marine too protective shell provides defense many can retract heads and appendages into shell box turtle has hinge that closes up head region dorsal protion of shell = carapace ventral portion of shell is plastron shell composed of hard, bony plates covered by keratinized scutes soft shell turtles pliable, leathery shell ribs, body vertebrae fused interior of carapace in turtles shoulder, hp girdles inside rib cage no teeth but have sharp keratinized covering over maxilla and mandible brain small, sense sight well developed dioecious and oviparous sex is determined by nest temperature temperature-dependent sex determination, high nest temperature results in females, low temperatures in nest result in males

animals, metazoans

35 phyla

Phylum Arthropoda, Subphylum Crustacea

68,000 members marine, some freshwater and terrestria free-living, some parsitic species hard chitinous and calcified cuticle that must be shed-ecdysis for animal to grow most have 2 tagmata - cephalothorax and abdomen number of body segments - 6-32 segments each with pair appendages more advanced - fewer appendages many have ahrdened carapace covers cephalothorax may extend past head form of rostrum different b/c have 2 pairs of anterior antennae first pair - antennules - shorter and associated with smell second pair - antennae longer - sensory structures modified mouthparts, mandibles, maxillae, maxillipeds with important feeding sensory function crabs, crayfish, lobsters - first pair walking legs, chelipeds modified to powerful claws other walking legs are biramous (having 2 branches) have feathery swimmerets or pleopods in abdominal region tail is nonsegmented telson flanked by fanlike uropods open circulatory system heart resides in blood-filled sinus with paired ostia (valves) to body food broken down physiclaly in large cardiac stomach and in smaller pyloric stomach, part of foregut excretion of nitrogenous wastes occurs by diffusion across gills most are dioecious fertilized eggs released into water or carried by female crustacean larval crustaceans are variable may include nauplius, zoea, megalops stages

Class Reptilia

7500 species major revision now - future - may use "nonavian reptiles" to describe turtles, lizards, snakes, tuataras, crocodiles mostern reptiles - oviparous or ovoviviparous, reptiles produce amniotic eggs ideal for transition to land eggs have yolk for nourishment and 4 membranes in development: yolk sac - food for embryo, amnion - encases, cushions embryo fluid-filled cavity, chorion - exchange of vital respiratory gases, allantois - colelcts metabolic waste water-tight shell of reptilian egg highly protective fertilization internal before egg forms tough,dry,scaly integument protect from desiccation and injury well ossified and strong skeleton limbs paird with 5 toes, except snakes, amphisbaenians and some legless lizards 2 sacral vertebrae support pelvic girdle lungs and thoracic breathing, specialized muscles and ribs provide for transport of copious amounts of air into/out of lungs crocodilians have 4 chambered heart, reptiles have 3 chambered heart ectotherms - depend on environment for thermoregulation complete digestive, kidneys urine voided in semisolid mass containing uric acidd crystals well developed lungs, kidneys, nervous system, sensory structures dioecious with no larval stage

Spiders all contain venom have four pair of walking legs have a cephalothorax (head and thorax) all of the above**

All of the above

Although there are no true tissues in these organisms, they are multicellular and have cells that are specialized. They have specific openings for the influx of water and a general opening called the osculum for the outflow of water. Poriferans Sponges Demispongia All of these are correct.

All of these are correct. Poriferans, Sponges, Demispongia

These limbless Amphibians live in tropical regions in moist burrows.

Caecilians

These sea-dwelling creatures have skeletal structures composed entirely of cartilage. They have highly developed sensory structures that run the length of both sides of their bodies.

Chondrichthyians

6 Classes of crustaceans Recognize 4 Classes of crustaceans

Class Branchiopoda - brine shrimp, tadpole shrimp, fairy shrimp Class Ostracoda - ostracods and seed shrimp Class Maxillopoda - barnacles, tongue worms, fish Class Malacostraca - lobsters, crabs, shrimp, pill bugs and other isopods Classes Remipedia and Cephalocarida have obscure crustaceans

Sponge Classes

Class Calcarea - small marine sponges with spicules composed of calcium carbonate asconoid, syconoid, leuconoid body forms Demospongiae - largest class of sponges monaxonal (needle-shaped). tetraxonal siliceous spicules Class Hexactinellida - glass sponge - 6 rayed spicules fused lattice

4 classes of Cnidaria

Class Hydrozoa - hydra and colonial species - hydroids Class Scyphozoa - true jellyfishes Class Cubozoa - box jellyfish Class Anthozoa - flower animals

Class Myxini and Cephalaspidomorphi

Class Myxini - bottom dwelling scavengers - hagfishes mouth has two keratinized plates toothlike structures small brain and eyes highly developed sense smell and taste slime glands lateral produce slime in self-defense Class Cephalospidomorphi (Petromyzontida) - lampreys nonparasitic do not feed after adulthood b/c alimentary canal degenerates spawn after adult stage and die, attach to fish with sucker like mouth sharp horny teeth suck out body fluids cause death of host anadromous - live in marine but return to freshwater to spawn parasitic as adults

3 Classes of Annelida

Class Polychaeta - marine worms, sandworms Class Hirudinea - leeches Class Oligochaeta - marine and terrestrial worms, earthworm some biologists suggest oligochaetes and hirudineans should constitute new class called Clitellata b/c both posses glandular structure used during reporoduction

6 Classes Molluscs

Class Polyplacophora - chitons Class Monoplacophora - organisms with cap-like shell Class Gastropoda - snails, abalone, whelks, limpets, slugs, nudibranchs Class Cephalopoda - octopi, squid, cuttlefish, nautiluses, fossil ammonites Class Bivalvia - clams, oysters, mussels, scallops Class Scaphopoda - tusk shells

4 Classes Platyhelminthes

Class Turbellaria - planaria - mostly free-living flatworms Class Cestoda - parasitic tapeworms Class Trematoda - flukes - all are parasitic Class Monogenea - ectoparasitic flatworms usually found on skin and gills of fishes

5 Classes of Phylum Echinodermata

Crinoidea, Asteroidea, Ophiuroidea, Echinoidea, Holothuroidea

Beetles belong to the order

Coleoptera

Beetles belong to the order Orthoptera Coleoptera** Hymenoptera Hemiptera

Coleoptera

radial symmetry

body parts arranged around central axis spokes of wheel jellyfish, adult starfish

3 Orders of Class Amphibia

Gymnophiona - limbless apodans caecilians - blind, sensory tentacles between eyes and nostrils - body in rings, annuli look like earthworm Caudata (Urodela)- salamanders, newts, amphiumas, sirens - lizard like, most have 4 toes on front legs 5 toes on hindlegs, lack claws Amphiumas and sirens degenerate legs - eellike appearance, some adults have lungs - some terrestrial species lack lungs and gills so have cutaneous respiration Anura - toads, frogs - toads dry, bumpy integument, parotid glands behind tympanic membrane, blunt nose, no webs on hind digits frogs have smooth, moist skin, teeth in upper jaw, webs behind hind toes, long muscular hind legs and front legs serve as shock absorbers adults frog/toads carnivorous, tadpoles herbivorous

gastrulation

In animal development, a series of cell and tissue movements in which the blastula-stage embryo folds inward, producing a three-layered embryo, the gastrula.

deuterostome development

In animals, a developmental mode distinguished by the development of the anus from the blastopore; often also characterized by enterocoelous development of the body cavity and by radial cleavage.

This Cnidarian is a colony of animals. The tentacles can reach over 50 feet from the bladder.

Man-O-War

A radula is a unique organ for feeding found in Molluscs Annelids Arthropods Only insects

Molluscs

A radula is a unique organ for feeding found in molluscs** annelids arthropods only insects

Molluscs

hookworms

Necator americanus hook-like anterior ends infect mammals - humans eggs pass in feces infected host juveniles hatch in soil barefoot where animals defecate not goo anemia and protein deficiency young children loss of proteins and iron retard growth

Clade Panarthropoda 3 Phyla

Phylum Arthropoda - insects and relatives Phylum Tardigrada - water bears Phylum Onychophora - velvet worms Panarthropods possess true coelom (body cavity) segmented body, appendages - legs and claws

3 Phyla of Deuterostomes

Phylum Echinodermata - spiny skinned animals - mostly marine Phylum Hemichordata - hemichordata (half chordates) marine previously placed in Chordata Phylum Chordata

8 phyla of protostomes

Phylum Nematoda - roundworms Phylum Nematomorpha - horsehair worms- Nematoidea Phylum Kinorhyncha - minute marine worms Phylum Priapulida - 16 species cole water marine worms

Bilateria consists of

Protostomia - Lophotrochozoa and Ecdysozoa Deuterostomia - Echinodermata and Chordata

Roly-poly Order Isopoda - class Malacostraca pill bug, sow bug,

Roly-poly Order Isopoda - class Malacostraca pill bug, sow bug, Isopod - Ligia spp. wharf roach ectoparasites of gill region of marine fishes massive claws on tips of each appendage that serve as holdfasts

Annelids have specialized structures on each segment that enable them to anchor their bodies into the soil. Some annelids have paddle-like appendages attached to these structures, while others have only bristles. Spicules Spiracles Setae None of these are correct

Setae

5 Subphyla

Subphylum Chelicerata - horseshoe crabs, ticks, mites, sea spiders, spiders, scorpions, extinct eurypterids Subphylum Myriapoda - centipedes and millipedes Subphylum Trilobita - extinct trilobites Subphylum Crustacea - crabs, shrimp, lobsters, crayfish, barnacles, copepods, pill bugs Subphylum Hexapoda - insects - largest subphylum

Trilobites

Subphylum Trilobita ancestors of arthropods first in Cambrian period aporoximately 540 million years ago extinct durnig Permian period 280 million years ago

3 Subphyla of Chordata

Subphylum Urochordata - nonvertebrate subphylum - tunicates (sea squirts) salps Subphylum Cephalochordata - nonvertebrate - sea lancelets Largest Subphylum is Vertebrata (Craniata) - fishes, amphibians, reptiles, birds, mammals

Animals have transformed ecosystems and altered the course of evolution.

The rise of animals coincided with the change from a microbe-only world to a world filled with large producers, scavengers, predators, and prey. The origin of animals with suspension-feeding mouthparts may have caused sweeping changes in early oceans, such as an increase in water clarity and a shift from cyanobacteria to algae as the dominant producers. The diversification of bilaterians in the sea and on land has changed biotic interactions and stimulated evolutionary radiations in other groups of organisms. Human actions have caused evolution by natural selection and have the potential to cause a mass extinction.

3 forms in sponges

asconoid - small tube shaped syconoid - large asconoid tubular with single prominent osculum leuconoid - most common complex own osculum

3 types of canal systems of sponges

asconoid, syconoid, leuconoid

sponges reproduce

asexually by budding or forming gemmules, structures that help them survive harsh conditions sexually - produce sperm and eggs unite form free-swimming larvae most are monoecious both sexes in same organism pores - ostia allow water in interior central cavity - spongocoel lined with flagellated collar shaped cells - choanocytes water eliminated from sponge by osculum flow of water allows food taken in and circulated within sponge and intake of sperm cells of sponges arranged in gelatinous matrix called mesohyl flat, thin cells pinacocytes cover exterior - form layer pinacoderm amoebocytes or archaeocyte cell moves in mesohyl and absorbs, digests, transports food amoebocytes involved in formation of spicules and spongin spicules siliceous or calcareous skeleton supportive structures some no spicules spongin provide support

chordates

bilaterian animals belong to animal clade Deuterostomia early evolution: share derived characters some only during embryonic development

Bilaterian Radiation I - Diverse Invertebrates

bilaterian animals diversified 3 major clades: Lophotrochozoa Ecdysozoa Deuterostomia dominated life in Cambrian oceans initially all these species were invertebrates

Lophotrochozoa

bilaterian clade members show greatest range in body form 18 animal phyla - more than twice number in any other clade of bilaterians vary in body form

Class Chondrichthyes

cartilaginous fishes sharks, rays, skates, sawfishes, chimaeras Gnathostomes have ventrally oriented mouth entire skeleton of Chondrichthyes including skull is cartilaginous paired pectoral and pelvic fins, 2 dorsal median fins males - pelvic fins modified aid in sperm transfer called claspers skin has placoid scales (dentricles or small teeth) and mucous glands teeth of sharks actually placoid scales complete digestion closed circulatory with 2 chambered heart 5-7 pairs of gill slits Spiracles found below eyes in sawfishes and rays draw water into gills many have well developed sense smell and hearing rays bottom-dwelling fishes with whiplike tail of serrated spines with venom glands at base rays ovoviviparous (eggs develop in femal w/o placental attachment and hatch imemdiately before birth) young develop in mother and nourished by yolk sac until birth some sharks ovoviviparous too but several viviparous (rather than producing eggs, produce embryo that develops inside female prior to birth) embryo receives nourishment from mother's bloodstream from placenta-like structure skates have flat body wth fleshy tail lacks spines different from rays by prominent dorsal fin have small teeth not grinding plates of rays oviparous (egg-laying) produce hard rectangular egg case called "mermaid's purse" critically endagered marine sawfishes sawlike rostrum covered with motion sensitive electrosensitive pores (ampullae of Lorenzini) like sharks, rays and skates that help detect prey movement rostrum can dig up prey buried in ocean floor or deadly slashing instrument Chimaeras AKA ratfish or ghostfish are ancient cartilaginous fishes that usually inhabit deep marine waters. Called chimaeras b/c appearance like patchwork of other animals

Jellyfish, hydra, and Portuguese-Man-of-War belong to the phylum porifera cnideria mollusca odonata

cnideria

ancestor to animals

colonial flagellated protist similar to today's chanoflagellates - 600 amd 550 million years ago, complex, soft-bodied multicellular animals first in fossil record

ctenophores

comb jellies

Phylum Ctenophora

comb jellies sea walnuts or sea gooseberries adjesive cells called colloblasts capture food don't possess nematocysts tentacles ctenophores solid, epidermis only swim by ros of fused cilia, comb plates many bioluminescent

Animals originated more than 700 million years ago

current evidence indicates that animals evolved from single-celled eukaryotes similar to present-day choanoflagellates biologists named more than 1.3 million species nearly 8 million species according to one recent study

tissues

groups of similar cells that act as a functional unit

Phylum Nematomorpha

horsehair worms digestive system vestigial structure lost function digestion through absorption free-living, found damp environments puddles, watering troughs barn juvenile stage encysts on plant eaten by cricket or grasshopper, juvenile develops in host eventually emerges

These chelicerates are called "living fossils".

horseshoe crabs

bilaterial symmetry

humans body can be divided into two mirrow images wasps

Phylum Cnidaria

jellyfish - see below majority are sessile Man-o-war own sail used for wind locomotion named for cell cnidoblast - cnidocytes contain stinging cells or nematocysts nematocysts aid in food gathering and defense 2 forms - dimorphism - medusa upside down cup with tentacles and polyp consists form tubular sessile body jellyfishes - medusa coral - polyp form several have life cycle with both forms radial symmetry diploblastic - no mesoderm muscular system made from contractile ectodermal and endodermal or epitheliomuscular cells mesoglea between epidermis and gastrodermis or endodermis amoebocytes within mesoglea aid in digestion, transport, storage, repair and defense against bacteria single opening in digestive system tentacles surround mouth digestion is extracellular no coelom no respiratory system gas exchange occurs through diffusion individual cells perform excretion possess nerve net neurites and sensory organs some are bioluminiscent produce own light asexual through budding many dioecious = male female gametes produced in individuals with gametes combine form embryo develops into ciliated planula larva

Poriferans, cnidarians

jellyfish, coral

Class Polychaeta

largest class of annelids more than 10,000 mostly marine worms paddle worms b/c parapodia fleshy structures bearing setae on each segment dioecious gamete production in individual segments or specialized portions of body most do not copulate, instead release gametes in water for external fertilization two subclasses errant polychaetes, subclass Errantia crawl on stones, shells, coral head and antennae parapodia large function like legs pharynx contains teeth and powerful jaws sedentary burrowers construct vertical burrow

Order Squamata

largest order of reptiles 7000 species of lizards, snakes, amphisbaenians skull with movable joints kinetic skull - allows them to seize, hold and swallow prey efficiently distinct scales males have hemipenis for copulation Jacobson's organ (vomeronasal organ) enhances sense of smell snake flicking tongue carrying back molecules to Jacobson's organ on roof of mouth for evaluation 2 living suborders are suborder Sauria (lizards and amphisbaenians) and suborder Serpentes snakes) most lizards terrestrial, some marine or aquatic elongated body and paired appendages except legless lizard ability to lose tail, many regenerate lost tail flag-like structure dewlap in throat region Amphisbaenians "worm lizards" lack limbs and auditory openings and underdeveloped eyes have independently moving rings used in locomotion 160 species identified most species of snakes harmless, rattlesnakes, coral snakes, cobras aren't snakes first appeared early Cretaceous period evolving from burrowing lizards boas and pythons oldest group still retain vestigial hindlimbs called spurs snakes - elongated body with numerous vertebrae up to 400 - ribs essential to locomotion complete digestive detect vibrations not good hearing lack eyelids, don't blink transparent membrane, spectacle over eyes oviparous, some ovoviviparous species exist

complete digestive tract

lions, squids tube within a tube

Phylum Mollusca

marine, freshwater, terrestrial chitons, limpets, slugs, snails, whelks, abalones, nudibrachs, oysters, scallops octopi giant squid giant clam herbivores, carnivores, filter feeders, detritus feeders parasites coelomates - coelom only limited to space around heart body plan - head-foot region and visceral-mass region majority have open circulatory system blood not in vessels gills or lungs gas exchange pair of metanephridia or kidneys opens into coelom through nephrostome radula - tonguelike organ used for rasping = teeth used for scrape, pierce, cut snail crawling up aquarium glass - teeth or radula rasping the algae nervous system especially cephalopods = in squid and octopi well developed mantle is sheath of skin from visceral mass protecting soft parts outermost surface of mantle responsible for secreting lining shell of some shell 3 layers - outer - periostracum - protect inner middle - prismatic - calcium carbonate and protein matrix inner layer nacreous layer - irridescent mother-of-pearl layer many molluscs secrete nacre around foreign or induced particles producing pearls dioecious external fertilization some internal fertilization trochophore larvae - molluscs and segmented worms (annelids) free swimming

Colonization of Land by Arthropods

millipedes, spiders, crabs, insects

Class Cephalopoda

modified foot in head region appears funnel shaped siphon used to expel water from mantle cavity surrounded by tentacles iwth suckers siphon used in jet propulsion expelling water during locomotion giant squid nautiloids chambered nautilus and paper nautilus external chambered shell cuttlefish small, curved shell enclosed by mantle called cuttlebone chambered gas-filled chamber keeps animal buoyant - pet stores sell it as a calcium source for birds shell of squid think strip called a pen Octopi no remnants of shell respiration through gills closed circulatory system with heart and valves brain is lobed largest of any invertebrate Octopi capable of learning - demonstrate complex behaviors many secrete dark sepia through ink glands serve as smoke screen during escape Octopi, squid cuttlefish change colors for seduction, warning, camouflage, communication, attraction of prey Chromatophores contain pigment granules, responsible for color and pattern changes Cioecious, juveniles hatch from eggs

Class Bivalvia

molluscs that have two separate shells (valves) joined by ligament called hinge oldest part of shell is umbo - large hump on anterior end of dorsal side of each valve adductor muscles hold valves of shell together with posterior and anterior adductor muscle scallops have only one clams or scallops eating adductor muscles bivalves hatchet-footed animals b/c hatchet-shaped muscular foot attached to viscral mass of organism bivalves: clams, mussels, scallops, oysters lack head and radula bivalves live marine and freshwater most are filter feeders take in water/nutrients through incurrent siphon eliminate by excurrent siphon gas exchange through mantle and gills mostly dioecious freshwater clams the trochophore larva develop into specialized veliger larva known as glochicium larva that attaches to fishes to complete their development

Duck-billed platypus and the spiny achidna are

monotremes

Phylum Hemichordata

most common are 80 species acorn worms belonging to class Enteropneusta body covered in mucus with 3 regions: proboscis, collar and trunk

Hookworms, dog and cat heartworms, roundworms, and C. elegans all belong to the phylum

nematoda

Lobe-fins

other major lineage of osteichthyans key derived character is presence of rod-shaped bones surrounded by thick layer of muscle in pectoral and pelvic fins Devonian 419-359 million yrs ago lived in brackish waters, coastal wetlands today - 3 lineages survive - coelacanths, lungfishes tetrapods - adapted to life on land , vertebrates with limbs and digits

Class Trematoda

parasitic flukes endoparasites of various vertebrates some ectoparasitic species exist most reside in lung,liver,bile ducts, pancreatic ducts, intestines, blood flattened leaflike covered by nonciliated syncytial tegument lacks cell membranes between the nuclei speciality glands for penetration or cyst formation, suckers hooks for attachment mouth anterior end ability produce tremendous number of offspring sense organs poorly developed share with turbellarians well-developed alimentary canal Chinese liver fluke - Asia parasitizes dogs, cats, pigs, humans fertilized eggs enter body of host land in water, ingested by snai, egg hatches forms miracidium larva into water burrow into fish First intermediate host - snail Second intermediate host - fish Final host - human when eats fish - to bile ducts Schistosoma - blood flukes - Africa - Schistomiasis

Metazoans - 35 phyla

parazoa - sponges other phyla designated Eumetazoa animals radial symmetry - Radiata Bilateral symmetry - Bilateria Bilateria - Protostomia - Lophotrochozoa and EcdysozoaDeuterostomia - Echinodermata and Chordata

Ecdysozoans

protective cuticle, exoskeleton spiders, insects, shrimp -ecdysis or molting basis for separation for ecdysozoans from lophotrochozoans trachea, gills, lungs, internal fertilizaton and metamorphosis impact on ecology, commerce, medicine

gastrulation, fate of blastopore resulted 2 major groups of animals:

protostomes - snails, leeches, ants gives rise to mouth deuterostomes - starfishes, stingrays, pelicans, monkeys blastophore gives rise to anal opening

Phylum Nematoda

pseudocoelomates = roundworms hookworms, pinworms, guinea worms, eye worms, heartworms, whipworms 25,000 known species "bad" bodies cylindrical and tapered both ends thick protective nonliving cuticle grows between molts fluid-filled pseudocoel well developed and serves as hydroskeleton move in thrashing motion produced by layer of longtitudinal muscle - motion allows them to move between spaces in algae, sand, soil mouth opens into buccal cavity with teeth or stylet (spear-like structure) connects to the pharynx long straight intestine serves site of digestion and absorption lack protonephridia possess glands tubules open through midventral pore to external environment nerve rings sensory papillae, non parasitic possess amphids sensory organs each side of head parasitic species have phasmids sensory organs near posterior end majority are dioecious with male smaller than female male usually copulatory spicules internal fertilization female eggs stored in uterus until deposition free living nematodes feed on bacteria, algae, yearst, fungi, small invertebrates other nematodes coprozoic nematodes feed on fecal material other may be saprobes some feed on juices plants roots causing crop damage parasitic forms variety diseases in humans and animals Caenorhabditis elegans model organism in genetic, developmental research Ascaris lumbricoides model typical nematode most common intestinal parasite in humans typical female prolific, producing + 200,000 eggs/day pass through host feces proper soil conditions undergo embryonation eggs viable in soil up to 10 years - enter body uncooked vegetables, soiled fingers intestinal wall , in lungs serious pneumonia lungs- larvae in trachea - reach pharnyx swallowed to stomach to intestines larvae mature feed on intestinal contents

pseudocoelomates

rotifers, roundworms (hookworms) coelom is derived from both the ectoderm and mesoderm

Spiders use these structures to spin webs. spicules spiracles spinnerets none of these are correct

spinnerets

Class Holothuroidea

sea cucumbers live on surface of substrates or burrow into sediments most dioecious, some hermaphroditic species fertilization external zygote into planktonic larvae when threatened, undergo evisceration - entire digestive system and other organs - gonads shot out of mouth or anus fleshy bodies with skeleton isolated ossicles embedded in muscular body lie on side by 3 ambulacra called the sole tentacles surround mouth and skeleton complete digestive system empties into muscular cloaca when threatened can rupture hindgut extruding Cuverian threads that wrap around enemy respiratory tree both respiratory and excretory structure

Phylum Chordata, Subphylum Cephalochordata

sea lancelets - slender, laterally compressed body resemble small lance or willow leaf blade generally translucent, inhabit sandy coastal waters may look like worm or larval fish bury posterior end into sand stick anterior end above sand to filter-feed amphioxus notochord and nerve cord entire length of body closed circulatory system gas exchange at surface of body small brain and simple sense organs - ocellus cioecious with gametes released from gonads to environment via atriopore fertilization is external segmented repeating muscle units myomeres feeding - water enters mouth passes to endostyle (dorsal groove) trapped by mucus mvoed to hepatic cecum, digested filtered water exits from atriopore and waste from anus possess diverticulum similar to vertebrate pancrease and liver

Class Echinoidea

sea urchins, sand dollars, sea biscuits we collect their test formed by fused ossicles of sand dollar live in deep ocean and intertidal zone sea urchins prefer rocky areas, sand dollars burrow into sediment dioecious with many producing planktonic larvae lack arms, but pentamerous parts on dorsal sidde of test armlike extensions petalloids sea urchins skeletal structure Aristotle's lantern with 5 hard "teeth" moved by complex struts and muscles used for grinding food sea urchins - large spines penetrate human skin

Phylum Arthropoda, Subphylum Chelicerata

six pairs appendages, 4 pairs walking legs, pair of chelicerae appendages (behind mouth used for feeding), pair of pedipalps (appendages aid in chewing) no attennae, no mandibles body 2 regions - cephalothorax and abdomen 3 classes of chelicerates - Merostomata, Pycnogonida, Arachnida **horseshoe crab - ancient lineage not changed since Triassic period only gill-bearing chelicerates carapace, ommatidia, telson, pincers, book gills visible on abdomen no hemoglobin in blood instead copper-rich protein hemocyanin harmless omnivores, scavengers feed on invertebrates and algae shed carapaces often, sexes separate fertilization external produce trilobite-like larvae

Phylum Arthropoda Subphylum Arachnida Order Araneae spiders

spiders - body - cephalothorax joined to abdomen by pedicel - possess chelicerae modified to form fangs complete with venom sacs pair of sensory pedipalps no antennae 4 pairs of walking legs most liquefy tissue of prey, suck liquid into digestive silk produced by silk glands opening into 2-3 pairs of spinnerets one spider Mastophora dizzydeani throw sticky ball-like web on end of thread capture prey book lungs tracheae or both used in breathing heart is long tube in abdomen pumps blood through body blood returns to heart via ostia from hemocoel Malpighian tubules extract nitrogenous waste and uric acid from hemocoel and release it into the cloaca nervous system well developed most have 8 eyes on top of antior region of cephalothorax slit sensillae in joints of limbs detect vibrations , especially when prety entangled in web courtship behavior fertilized eggs develop in cocoon hidden or carried by female some - female devours male shortly after mating defense, tarantulas release urticating hairs deliver painful bite

Class Arachnida

spiders, scorpions, mites, ticks, harvestmen (daddy longlegs) terrestrial predators, fangs, claws, poison glands, stingers sucking mouthparts suck fluids and soft tissues from prey two tagmata, cephalothorax, abdomen cephalothorax - head region, thorax head - pair pedipalps, pair chelicerae,4 pairs walking legs claws or chelae scorpions are modified pedipalps harvestmen not spiders belong to order Ophiliones feeding mechanism devour pieces of food fungi insects instead of liquids

Order Acari

ticks, mites, chiggers large 40,000 species freshwater marine terrestrial most free-living, some parasitic medically significant cause diseases in humans house or dust mites - allergies larval chiggers - dermatitis Sarcoptes scabiei cause scabies Demodex canis - demodectic mange ticks ectoparasite on animals ticks vector for lyme disease and Rocky Mountain spotted fever

eucoelomates

true coelomates body cavity derived from only mesodermal tissues

Class Scyphozoa - drinking cup

true jellyfishes polyp stage reduced or absent dominant stage bell-shaped medusa male female form zygote retained on oral arms of medusa then ciliated planula larva that lands on substrate forms scyphistoma grows asexually, buds forms asexual strobila then gives rise to swimming ephyra, eventually develop into medusa

The distinction between sponges and other animal phyla is based mainly on the absence versus the presence of

true tissues.

Phylum Onychophora

velvet worms part of clade Panarthropoda possess hemocoel lined by extracellular matrix open circulatory blood enter hemocoel bathes internal organs muscular heart blood vessels

Phylum Chordata, Subphylum Vertebrata (Craniata)

vertebrates have body plan of chordates: notochord, pharyngeal pouches, dorsal hollow nerve cord, postanal tail some vertebrates - notochord found only in embryos - guides development of vertebrae majority - vertebral column surrounds or replaces notochord spinal cord forms from dorsal hollow nerve cord brain forms anterior end of nerve cord encased in cranium some jawless fish , hagfish, lack vertebrae keep their notochord ALL members of subphylum Vertebrata (Craniata) have skull or cranium craniates have neural crest - group of embryonic cells that contribute to forming cranium, jaws, teeth some nerves metabolically more active than protochordates and possess more complex muscular system bony or cartilaginous endoskeleton with cranium, limb girdles, 2 pairs of appendages to keep metabolic rate higher members have multichambered heart (2-4 chambers) hemoglobin-rich blood specialized organs - liver, kidneys endocrine system well developed +55,000 species 2 Superclasses: Agnatha (jawless fishes) Gnathostomata (jawed vertebrates) Agnatha (jawless fishes) - class Myxini (hagfishes) and class Cephalaspidomorphi (lampreys) 70 species of jawless fishes - lack scales, internal ossification, paired fins - eellike bodies paired pore-like gill openings Gnathostomata (jawed vertebrates) more familiar jaws, feeding devices to grasp, crush, shear, chew Six classes: Chondrichthyes (cartinlinous fishes) Osteichthyes (bony fishes) Amphibia (amphibians) Reptilia (reptiles) Aves (birds) Mammalia (mammals)

Phylum Tardigrada

water bears possess hemocoel lined by extracellular matrix most are microscopic found living film of water associated with moss, lichens, detritus, or moist plants marine and freshwater polyextremophyles surviving both low and high temperatures, high radiation, dry conditions and NASA determined = space under extremely harsh conditions - enter cryptobiotic ametabolic state stubby body four pairs short unjointed legs pair stylets near buccal tube allow to pierce plant or animal walls some eat entire rotifers, othe rtardigrades, small invertebrates brain large, nerve cord - 4 ganglia control legs dioecious

These parasitic worms are ingested (usually accidentally swallowed), carried through the lungs and then to the throat where they are swallowed. Once swallowed, they reach the intestines and develop into adult worms. platyhelminthes ascaris annelids none of these are correct

Ascaris

Invertebrate diversity

Bilaterian invertebrates account for 95% of known animal species occupy almost every habitat on Earth variation in size morphological diversity mirrored by taxonomic diversity vast majority members of 2 bilaterian clades merged from Cambrian Lophotrochozoa and Ecdysozoa Deuterostomia includes some invertebrates

Fossil steroid and molecular clock evidence suggests that animals originated? -between 710 and 770 million years ago -more than 100 million years before the oldest known fossils of large animals during the Cambrian explosion

both a and b -between 710 and 770 million years ago -more than 100 million years before the oldest known fossils of large animals

Diverse animal groups radiated in aquatic environments

end of Cambrian explosion many big steps animal evolution under way

Animals have transformed ecosystems and altered the course of evolution

rise of animals most monumental change in history of life transformation of microbe-only world to world filled with large producers, predators, prey change affected all aspects of ecological communities, in sea and on land

3 aspects of animal body planes

symmetry, tissues, body cavities

Bilaterian Radiation II: Aquatic Vertebrates

vertebrates members of phylum Chordata

Amniotes have key adaptation for life in a wide range of terrestrial environments

A more extensive colonization of dry habitats occurred in amniotes, a group of tetrapods that originated 350 million years ago and whose living members are reptiles and mammals. Amniote adaptations for life on land include the amniotic egg, rib cage ventilation, and skin (covered by scales or hair) that limits evaporative water loss. Extant reptiles include tuataras, lizards and snakes, turtles, crocodilians, and birds. Birds are the most diverse reptile group; many traits in birds are adaptations facilitating flight. Unique traits of mammals include mammary glands and hair. Mammals have diversified into the egg-laying monotremes, the pouched marsupials, and the placental eutherians. Hominins-humans and extinct species more closely related to humans than to chimpanzees-originated in Africa 6-7 million years ago. Early hominins walked upright but had a small brain. Homo sapiens originated in Africa 195,000 years ago and spread from there to other continents.

protostome development

In animals, a developmental mode distinguished by the development of the mouth from the blastpore; often also characterized by schizocoelous development of the body cavity and by spiral cleavage.

Vertebrates have been ocean's dominant predators for more than 400 million years

Myllokunmingia fengjiaoa - ancient species lacking armor and appendages closely related one of most successful groups of animals ever to swim, walk, fly, slither, vertebrates derive name from vertebrae - series of bones make up backbone

The diversity of large animals increased dramatically during the "Cambrian explosion"

Prior to the Cambrian explosion (535-525 million years ago), virtually all large animals were soft-bodied and poorly defended. Fossils dating to the Cambrian explosion include the oldest known members of many living animal phyla. Fossil and molecular evidence suggests that bilaterians had emerged by 635 million years ago.

Diverse animal groups radiated in aquatic environments.

The diverse animals that emerged from the Cambrian explosion can be categorized by their body plan, the morphological and developmental traits that are integrated into a functional whole. Most living animals are bilaterians, bilaterally symmetric animals with three tissue layers and a complete digestive tract. Bilaterally symmetric animals have diverged into three major clades: Lophotrochozoa, Ecdysozoa, and Deuterostomia. These clades include diverse invertebrate phyla whose early members dominated life in the Cambrian oceans.

Several groups had features facilitating their colonization of land

Unlike plants, whose ancestors colonized land only once, many animal groups have made the transition to terrestrial life. Animals that colonized land were "pre-adapted" for their new environment in that they typically had a complete digestive tract and well-developed skeletal, muscle, and nervous systems. Arthropods were the first animals to colonize land, about 450 million years ago. The insects radiated explosively and now comprise more known species than all other eukaryotic groups combined. Vertebrates colonized land 365 million years ago when early tetrapods arose from aquatic lone-fins. Early tetrapods remained tied to water, a characteristic they share with most amphibians.

Vertebrates have been the ocean's dominant predators for more than 400 million years

Vertebrates originated 500 million years ago. The earliest vertebrates lacked jaws. Gnathostomes (vertebrates with jaws) arose 440 million years ago. Three lineages of jawed vertebrates survive today: chondrichthyans, ray-finned fishes, and lobe-fins.

Which of the following could be considered the most recent common ancestor of living tetrapods? -a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates -an armored gnathostomes with two pairs of appendages -an early ray-finned fish that developed bony skeletal supports in its paired fins -a salamander that had legs supported by a bony skeleton but moved with the side-to-side bending typical of fishes

a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates

mesoderm

all bilaterally symmetric animals have 3 germ layers fills much of space between the ectoderm and endoderm. In bilaterally symmetric animals, mesoderm forms the muscles and most other organs between the digestive tract and the outer covering of the animal

choanocytes

collar cells named for finger-like projections that form a collar aroudn the flagellum cells engulf bacteria and other food particles by phagocytosis resemble cells of choanoflagellates similarities between DNA of sponges and choanoflagellates may have evolved from choanoflagellate-like ancestora

Tissues

collections of specialized cells that act as a functional unit in animals true tissues are isolated from other tissues by membranous layers Sponges lack true tissues Other animals, embryo becomes layered during development

"Cambrian explosion"

early Cambrian period 535-525 million years ago large forms of many other present-day animal phyla suddenly appear, phenomenon referred to as the Cambrian explosion Evolutionary change: first arthropods, chordates, echinoderms most animals from explosion are bilaterians

Marine Ecosystems

fossil biochemical evidence suggests abundance of cyanobacteria decreased in early Cambrian may caused by activities of crustaceans and other animals with suspension-feeding mouthparts. suspension feeders can process enormous amt. water every 20 days, animals filter volume of ocean water is estimated to be equal to that in which most organisms live as early suspension-feeding animals removed cyanobacteria and other suspended matter from water and ocean waters would have become clearer. Resulting in algae require more light for photosynthesis than cyanobacteria increased in abundance moved to deeper waters water clarity, algae dominant producers, different feeding relationships emerged small animals that ate marine producers and detritus evolved and were eaten by large animals which were eaten by larger animals explosion of animal diversity in early Cambrian marked end of microbial world and beginning of ocean life today - predators, grazers, suspension feeders, scavengers all shapes,sizes

Early-Diverging Animal Groups

fossil evidence and molecular analyses identified certain animal groups as having diverged from all other animals early in animal evolution Sponges and cnidarians

Evidence of selection for defensive adaptations in Mollusc Populations Exposed to Predators?

fossil record shows historically, increased risk to prey species from predators often accompanied by increased incidence and expression of prey defenses Researchers tests populations of predatory European green crab Carcinus maenas have exerted similar selective pressure on its prey, flat periwinkle Littorina obtusata Periwinkles from southern sites in Gulf of Maine have experienced predation by European green crabs for over 100 generations, at about one generation per year. Perwinkles from northern sites in Gulf been interacting with invasive green crabs for few generations as invasive crabs spread to northern Gulf comparatively recently. Researchers collected periwinkles and crabs from sites in norther/southern Gulf of Maine separated by 450 km coastline. Single crab placed in cage w/ 8 periwinkles. 3 days - fate of periwinkles - p. 570

ectoderm

germ layer covering the surface of the embryo in some phyla to the central nervous system

Which clade does NOT include humans? -Ctenophora and Cnidaria -Lophotrochozoa and Ecdysozoa -Cnidaria and Platyhelminthes -Echinodermata and Hemichordata

lophotrochozoans

synapsides

mammals originated from lacked hair, sprawling gait, laid eggs 120 million yrs, ancestors gave rise to mammal-like synapsides diverse set of mammals coexisted w/ dinosaurs from 180 to 66 million yrs ago, species not abundant most measured less than 1 m explanation for small size dinosaurs occupied ecological niches large-bodied animals 180 million yrs ago first true mammals arose

This mammal has a furry body, bill, and webbed feet. It also lays eggs. As it is a mammal, it produces milk for its young. What kind of mammal is it? none of these marsupial eutherian monotreme**

monotreme

3 Major lineages of mammals emerged

montremes - egg-laying mammals marsupials - mammals whose young are born as embryos and complete development in an external pouch eutherians - placental mammals whose young complete embryonic development in uterus after dinosaurs extinction 66 million yrs ago, mammals diversify, resulting more than 5300 species today

Body Cavity

most bilaterians have body cavity - fluid or air-filled space located between digestive tract and outer body wall. Also called coelom Inner and outer layers of tissue surround cavity connect form structures that suspend internal organs functions: cushions suspended organs prevent internal injury in soft-bodied bilaterians - earthworms - coelom contains noncompressible fluid acts like skeleton muscles work cavity enables internal organs grow,move independently of outer body wall if not for your coelom, every beat of heart or ripple of intestine would warp body's surface

Hookworms, dog and cat heartworms, roundworms, and C. elegans all belong to the phylum annelida nematoda platyhelminthes mollusca

nematoda

body plan

particular set of morphological and developmental traits, integrated into a functional whole - the living animal. Body plans provide a succinct way to compare and contrast key animal features

Fossil and Molecular Evidence

researchers unearthed 710 million yr old sediments chemical evidence of steroids today primarily produced by particular group of sponges. sponges are animals "fossil steroids" suggest that animals had arisen by 710 million years ago molecular clock study estimated sponges originated 700 million years ago common ancestor of all extant (living) animal species lived about 770 million years ago first generally accepted macroscopic fossils of animals date from about 560 million years ago

Evolutionary Effects of Animals

rise of animals set in motion series of profound evolutionary changes many resulting from animals make life dangerous mobile, heterotrophic animals w/ complete digestive tract drove some species to extinction and initiated ongoing "arms races" between bilaterian predators and prey

bilateral symmetry

two-sided symmetry of a shovel bilateral animal has two axes of orientation front to back and top to bottom animals have dorsal (top) side and ventral (bottom) side, left side and right side and an anterior (front) end and a posterior (back) end nearly all animal with bilateral symmetry such as arthropods and mammals have sensory equipment concentrated at their anterior end typically move actively from place to place. most have central nervous system enables them to coordinate the complex movements involved in crawling, burrowing, flying or swimming

radial symmetry

type of symmetry found in a flowerpot sea anemones have top, bottom side, no front and back ends, no left no right sides many radial animals are sessile (living attached to a substrate) or planktonic (drifting or weakly swimmings such as jellies) their symmetry equips them to meet the environment equally from all sides

Origin of Tetrapods

Devonian 419-359 million yrs ago - lobe-fins lived coastal wetlands those that entered shallow, oxygen poo water could use lungs to breathe air some species used stout fins to swim and "walk" underwater bottom - using fins alternating gait as living lobe-fins suggests tetrapod body plan didn't evolve out of nowhere - modification of preexisting body plan fossil recently discovered Tiktaalik new details how p. 560 species had fins,gills, lungs, body covered scales unlike fish had full set ribs, helped breathe air support body - had neck, shoulders, move head unlike fish like limbed animals had one bone humerus, two bones, radius ulna, small bones wrist unlikely walked but proppered up in water on fins oldest known tetrapod - Tiktaalik - key tetrapod traits - wrist, ribs, neck ancestral to tetrapod lineage fossil record of first tetrapod 365 million yrs ago next 60 million yrs, diversity tetrapods retained functional gills, weak limbs, other lost gills, stronger limbs facilitated walking land fossil locations and morphology early tetrapods remained tied to water characteristic shared w/ member most basal group living tetrapods - amphibians

Reciprocal selection

Madagascar orchid Angraecum sesquipedale secretes a sugary nectar solution to base of unusually long floral tube.Charles Darwin predicted the existence of a pollinating moth w/ a 28 cm long proboscis long enough to reach the bottom of the tube discovered two decades after Darwin's death interpret data from a study of selection occurring in predator-prey interaction over time. reciprocal selective pressures also occur when origin of new species in one group of organisms stimulate further radiations in other organisms stimulate further radiations in other organisms, especially those that can eat, escape from, or compete effectively with the new group. as animal groups have diversified, they often had this effect new group of animals provides new sources of food for parasites, organisms that feed on single host species. result - ongoing diversification of animals led to evolutionary radiations in many groups of parasites - animals, fungi, protists, bacteria that can feed on newly evolved animal host

Animals originated more than 700 million years ago

The earliest evidence of animal life comes from fossil steroids indicative of sponges that date to 710 million years ago. The first fossils of large animals date to 560 million years ago and include sponges as well as fossil organisms that resemble living cnidarians and molluscs. Unlike nearly all other animals, sponges lack true tissues. Cnidarians are an early-diverging group of eumetazoans, an animal clade whose members have tissues.

Cnidarian

all animals except sponges and few other groups are eumetazoans "true animals" clade with tissues phylum Cnidaria 680 million years ago sessile and motile hydrozoans, jellies, sea anemones sac with central digestive compartment - gastrovascular cavity functions as both mouth and anus carnivores - use tentacles arranged in ring around mouth capture prey and pass food into gastrovascular cavity enzymes secreted into cavity break down prey nutrient-rich broth cells lining cavity absorb nutrients complete digestive process undigested remains expelled mouth/anus muscles nerves simple no brain nerve net sensory structures distributed throughout body can detect respond to stimuli from all directions

Diversification of Animals Hox genes

animals with different body plants rose early Cambrians, thrived period, then extinct no descendants by 500 million years ago, most animal phyla with members alive today were established evolutionary relationships among living animals provide helpful framework for studying rise of animals estimated using ribosomal RNA (rRNA) genes Hox genes, hundreds protein-coding nuclear genes, mitochondrial genes, morphological traits 3 dozen phyla recognized

General Characteristics of Arthropods

appendages through evolution become modified, specializing in functions walking, feeding, sensory reception, reproduction, and defense are jointed, come in pairs BODY: completely covered by CUTICLE - exoskeleton constructed from layers of protein and polysaccharide chitin (crab or lobster) rigid EXOSKELETON protects animal provides points of attachment for muscles that move the appendages later, exoskeleton allowed them to live on land exoskeleton impermeability to water helped prevent desiccation (drying out) and strength provided support when they left buoyancy of water specialized gas exchange organs evolved most aquatic species have gills with thin, feathery extensions place extensive surface area in contact w/ surrounding water Terrestrial arthropods have internal surfaces specialized for gas exchange most insects have tracheal systems, branched air ducts leading into interior from pores in cuticle ducts infiltrate the body, carrying oxygen directly to cells.

Insects

arthropod group colonized land now found in almost every terrestrial habitat live in fresh water, flying insects fill the air are RARE, but not absent in marine habitats oldest insect fossils date 416 million yrs ago then explosion in insect diversity when insect flight evolved during Carboniferous and Permian periods 359-252 million yrs ago animal that can fly can: escape predators, find food and mates, disperse to new habitats more effectively than an animal that must crawl on the ground insects have 1-2 pairs of wings that emerge from dorsal side of thorax b/c wings extensions of cuticle, insects fly w/o sacrificing any walking legs flying vertebrates - birds and bats - have one of 2 pairs walking legs modified into wings, making them clumsy on ground insects radiated in response to origin of new plant species provided new sources of food **insect population feeding on new plant species can diverge from other populations, eventually forming a new species of insect fossil record diverse insect mouth parts suggests that specialized modes of feeding on gymnosperms and other Carboniferous plants contributed to early adaptive radiations of insects later, another increase insect diversity stimulated by evolutionary expansion of flowering plants during mid-Cretaceous period 100 million yrs ago insect/plant diversity decreased during Cretaceous mass extinction, both groups rebounded over past 66 million yrs

Terrestrial Ecosystems

before animals joined plants and fungi onshore, terrestrial ecosystems simple structure: Producers - (early plants) - harnessed energy from sun and drew essential nutrients from soil, while decomposers (fungi and bacteria) returned nutrients to the soil 410 million yrs ago, animals had transformed these ecosystems. new biotic interactions in place - plants consumed by herbivorous animals, then eaten by predators other animals detritivores consumed organic debris, network of ecological interactions much of it driven by animlas lesser snow goose Chen caerulescens migratory bird breeds in marsh lands bordering Canada's Hudson Bay illustrates impact animals have on terrestrial communities. These birds feed on grasses and other marsh plants low population numbers, lesser snow geese improve growth of marsh plants, due to fact birds defecate every few minutes as they feed. adding nitrogen to the soil high numbers of birds feeding destroy a marsh, converting it to mudflat predators large effects - arctic fox introduction to islands between Alaska and Russia transformed habitats on islands from grasslands to tundra - change occurred b/c foxes fed upon seabirds, reducing their numbers = less bird guano, primary source of nutrients for plants on these islands reduction of nutrients favored slow-growing tundra shrubs instead of grasses, causing grasslands to be replaced

Human Impacts on Evolution

can be seen from window of airplane or satellite photographs humans dramatically altered global environment. With making these large changes, also altered selective pressures faced by many species. We are likely causing evolutionary change - and we are. sing antibiotics to kill bacteria, we have inadvertently caused evolution of resistance in bacterial populations. Also caused evolutionary change in species we hunt for sport or food. cod fisheries, commercial fishing operations target older and larger fish which led to reduction in age and size at which individuals reach sexual maturity . natural selection favored fish that mature younger age smaller size b/c they are more likely to reproduce before caught than are mature fish when older and larger human actions also drive species to extinction, altering future course of evolution. unless dramatic preventative measures taken sixth human-caused mass extinction may occur taxa under threat: molluscs animal group with largest number of documented extinctions pearl mussels, group of freshwater molluscs make natural pearls are among world's most endangered animals. Thirty become extinct in last 100 yrs nearly 200 of the 270 that remain threatened by extinction threats faced: habitat loss, pollution competition or predation by nonnative species, overharvesting reducing water pollution and changing how water is released from dams have led to dramatic rebounds in pearl mussel populations. The history of life shows that biological diversity is the product of branching phylogeny not ladderlike "progress" however we choose to measure it. The fact that there are almost as many species of ray-finned fishes alive today as in all other vertebrate groups combined is a clear indication that our finnned relatives are not outmoded underachievers that failed to leave the water. Ubiquity of diverse prokaryotes throughout biosphere today is reminder of enduring ability of these relatively simple organisms to keep up with the times through adaptive evolution. Biology exalts all of life's diversity, past and present.

Birds

diverse group of flying reptiles arose 160 million yrs ago characters of birds adaptations that facilitate flight, weight-saving modifications that make flying more efficient -lack urinary bladder females most species have only one ovary gonads of females and males small, except during breeding season - increase in size living birds toothless, adaptation trims weight of head wings and feathers for adapted for flight shape and arrangement of feathers form wings into airfoils, same principles of aerodynamics as wings of an airplane Flapping wings powered by contractions large pectoral (breast) muscles anchored to sternum (breastbone) Benefits of Flight: escape from earthbound predators. lungs have tiny tubes lead to and from elastic air sacs improve airflow and oxygen uptake efficient respiratory system and circulatory system with 4 chambered heart keep tissues well supplied with oxygen and nutrients, supporting high rate of metabolism acute vision, fine muscle control color vision, excellent eyesight visual and motor areas of brain well developed brain proportionately larger than amphibians and nonbird reptiles

bilaterians

enormous clade from Cambrian explosion whose members typically have a complete digestive tract and two-sided (bilaterally symmetric) form include molluscs, arthropods, chordates, and most other living animal phyla Previously, virtually all large animals were soft-bodied fossils of large pre-Cambrian animals reveal little evidence of predation grazers feeding on mats of algae and bacteria, filter feeders, or scavengers not hunters 10 million years, predators emerged over 1 m long, claws, other features capture prey decline in diversity of Ediacaran life-forms fossil evidence suggests during Cambrian period, predators acquired novel adaptations - forms of locomotion helped catch prey, prey acquired defenses like protective shells natural selection led to decline of soft-bodied Ediacaran species rise of various bilaterian phyla increase in atmospheric oxygen preceded Cambrian explosion enabled animals higher metabolic rates, larger body sizes to thrive harming other species ? origin of Hox genes affecting the regulation of developmental genes evolution new body forms

Arthropoda

first to colonize land billion estimated 1 million described - most are insects most successful of animal phyla - species diversity, distribution, sheer numbers due to body plan - segmented body, hard exoskeleton, jointed appendages Arthropod means "jointed feet" earliest fossils from Cambrian explosion 535-525 million yrs ago) Cambrian contains species lobopods - group arthropods may have evolved from Hallucigenia - segmented bodies segments identical early arthropods - trilobites little segment variation evolve = segments fuse become fewer, appendages specialized functions = great diversification efficient body plan permits division labor body regions Arthropods today two unusual Hox genes influence segmentation researchers study Hox genes in onychophorans - close relatives of arthropods results indicate diversity of arthropod body plans did NOT arise from acquisition of new Hox genes but by changes in sequence or regualtino of existing Hox genes

Homo sapiens

fossil evidence indicates ancestors of humans originated in Africa older species gave rise to later species including species H. sapiens oldest fossils our species found 2 sites Ethiopia include specimens 195,000 and 160,000 yrs old recent DNA analysis shed light on human origins revealing that all living humans are more closely related to one another than to Neanderthals, living humans have ancestors originated as H. sapiens in Africa - extract DNA from Neanderthal fossils and sequence Neanderthal genome oldest fossils of H. sapiens outside Africa from Middle East and date back 115,000 yrs. fossil evidence and genetic analyses suggest that humans spread beyond Africa in one or more waves - first - Asia, then Europe- then Australia date first in New World uncertain oldest accepted evidence date 15,000 yrs ago As they spread from Africa to rest of world, entered regions inhabited by Neanderthals and other (now-extinct) hominins Did they mate with with any of these species leading to interspecific gene flow? researchers show mixture of human and Neanderthal characteristics 2015 most extensive evidence yet of such gene flow reported analysis of human jawbone excavated from Romanian cave showed contained long stretches of Neanderthal DNA, indicating this individual's great-great-great- grandparent was a Neanderthal

Ediacaran biota

fossils members of early group of soft-bodied multicellular eukaryotes known collectively name comes from Ediacara Hills of Australia where fossils of these organisms first discovered among these fossils that resemble animals, some may be sponges while others thought to be cnidarians (sea anemones and their relatives) or molluscs (snails and their relatives)

Primates

group of eutherians includes lemurs, tarsiers, monkeys, apes humans member of ape group earliest known primates tree-dwellers, many derived characters of primates adaptations to demands of living in trees - grasping hands, feet allow primates hang on tree branches also have thumb relatively movable and separate from fingers monkeys and apes have fully opposable thumb - can touch the ventral surface (fingerprint side) of the tip of all four fingers with ventral surface of thumb same hand have large brain, short jaws giving flat face forward-looking eyes close together on front of face overlapping visual fields forward-facing eyes enhance depth perception- advantage when swinging from branch to branch nonhuman apes found exclusively in tropical regions Africa and Asia all living apes relatively long arms, short legs, no tail most nonhuman apes spend time in trees, only gibbons and orangutans primarily arboreal gorillas and chimpanzees highly social apes have larger brain in proportion to body size behavior more flexible 2 characteristics especially prominent in hominins

amniotes

group of tetrapods whose extant members are reptiles (including birds) and mammals amniotes named for major derived character of the clade: amniotic egg amniotic egg - contains 4 specialized membranes: the amnion, the chorion, the yolk sac, the allantois amniotic egg key evolutionary innovation for terrestrial life - allowed embryo to develop on land in its own private "pond" reducing dependence of tetrapods on aqueous environment for reproduction unlike amphibians (shell-less egg) amniotic eggs most reptiles and some mammals have shell shell slows dehydration of egg in air, adaptation helped amniotes to occupy wider range of terrestrial habitats than amphibians, closest living relatives mammals lost eggshell, embryo avoids dessication by developing within amnion inside mother body trait enables survive on land - use of rib cage ventilate lungs = more efficient than throat-based ventilation amphibians use as supplement to breathing through their skin increased efficiency of rib cage ventilation may have allowed amniotes abandon breathing through skin develop less permeable skin conserving water

Lineages of jawless vertebrates (cyclostomes) survive today

hagfishes and lampreys living jawless vertebrates outnumbered by jawed vertebrates

Ray-finned fishes have a flexible skeleton made of cartilage have a protective operculi to protect the gills** includes sharks and rays none of these are correct

have a protective operculi to protect the gills

gnathostomes

jawed vertebrates appeared in fossil record 440 million years ago became more diverse success from combination anatomical features - paired fins and tail allowed efficient swimming after prey jaws facilitated feeding enabling grab prey whole or bite chunks of flesh earliest gnathostomes include extinct lineages armored vertebrates placoderms "plate-skinned" by 420 million yrs, gnathostomes diverged to include 3 lineages of jawed vertebrates survive today: chondrichthyans, ray-finned fishes, lobe-fins last group included humans and terrestrial animals w/ legs

Terrestrial Vertebrates

key event in colonization of land by animals - 365 million yrs ago when fins of lineage of lobe-fins evolved into limbs/feet of tetrapods. Before, all vertebrates shared same basic fish-like anatomy after colonization of land early tetrapods gave rise many new forms- leaping frogs-flying eagles to bipedal humans MOST SIGNIFICANT CHARACTER of tetrapods its name - "four feet" in Greek in place of pectoral and pelvic fins have limbs with digits - support tetrapod's weight on land, feet with digits efficiently transmit muscle-generated forces to ground walking differ from earlier vertebrates having neck, consists of vertebrae separate head from body, neck allows head move up/down, side to side, independently from rest of the body bones of pelvic girdle fused to backbone, permitting fores generated by hind legs against the ground transferred rest of body

Early land animals

life on land higher concentrations of oxygen than aquatic new sources of food - early plants few competitors challenges: water scarce, temperatures fluctuated greatly than aquatic, no support against gravity potentially lethal soft body of jelly no support against gravity so can't move or survive on land arthropods - invaded land many times - recently 4 million yrs ago crab lineage colonized island Jamaica Fossils suggest arthropods first animals to colonize land - 450 million yrs ago evidence- fragments arthropod remains, possible millipede burrows fossils indicate 410 million yrs ago millipedes centipedes spiders wingless insect variety colonized land vertebrates colonized land 365 million yrs ago 360 million yrs ago - terrestrial animal communities broadly similar to those of today included predators, detritivores (animals tat eat decaying organic matter such as plant debris) and herbivores land animals bear resemblance to aquatic relatives sometimes so strong appears like walked from ocean to land - snails, crabs land crabs return to water to reproduce in vertebrates, evolutionary changes involved in transition to terrestrial life less extensive than those that occurred in plants. ex: aquatic relatives colonized land well-developed skeletal, muscular, digestive, circulatory, respiratory, nervous systems all of which facilitated the colonization of land. Plants in contrast - arose from small green alga structure bore little resemblance to its descendants - plants that now cover Earth

amoebocytes

mobile cells of sponges named for use of pseudopodia as cells move through sponge body, take up food from surrounding water and from choanocytes, digest it, and carry nutrients to other cells

Present-day animals are dangerous feeding machines because of?

mobility, nervous system, efficient digestive tract bilaterians

Early human ancestors

molecular data show among living apes humans and chimpanzees closest relatives to each other human and chimpanzee genomes 99% identical we're more closely related to Australopithecus and other extinct human ancestors Fossil evidence and genetic analyses indicate the evolutionary lineage leading to humans diverged from other apes between 6 and 7 million yrs ago species in this lineage known as hominins - group consisting of humans and the extinct species more closely related to us than chimpanzees oldest hominin fossils are of Sahelanthropus tchadensis lived 6.5 million years ago they and other early hominins shared derived characters of humans had reduced canine teeth, flat faces showed signs of being more upright, bipedal than other apes and this long before brains increased in size Ardipithecus ramidus = species showed signs of bipedalism, yet brain much smaller than H. sapiens fossils show that by 2.5 million yrs ago, extinct relatives walked upright and used tools but still had brain size of softball earliest fossils place our genus, Homo include Homo habilis, lived 2.4 - 1.6 million yrs ago H. habikis shorter jaw and larger brain volume 675 cm3 species - H. neaderthalensis (Neanderthal) lived in Europs by 350,000 yrs ago had brain larger than present-day human, buried their dead, made hunting tools from stone and wood became extinct between 28,000 and 40,000 yrs ago time our species reached Europe and other regions world

4 Key Characters of chordates:

notochord - dorsal, hollow nerve cord pharyngeal slits or pharyngeal clefts - muscular, post-anal tail blade-shaped animals lancelets closely resemble idealized chordate diverged from other chordates at base of chordate phylogenetic tree tunicates diverged from other chordates early in chordate evolution and display key chordate traits only as larvae adult tunicates have highly modified body plan ancestral chordate may have looked like lancelet - anterior end with mouth, notochord, dorsal hollow nerve cord, pharyngeal slits and post-anal tail after basic chordate body plan = origin vertebrates vertebrates have backbone, skull, well-defined head with brain, eyes, other sensory organs earliest chordate- Myllokunmingia only had brain and eyes, parts of skull around eyes and ears, one of earliest chordates with well-defined head - lacked vertebrae not classified as vertebrae early ears organs for maintaining balance - function still performed by human ears

Rise of Vertebrates

originated 500 million years ago. More complex nervous system more elaborate skeleton became more efficient 2 essential tasks: capturing food and avoiding being eaten earliest fossil vertebrates conodonts, soft-bodied jawless vertebrates hunted by impaling prey on set barbed hooks in mouth early vertebrates paired fins and inner ear with 2 semicircular canals that provided sense of balance lacked jaws had muscular pharynx -used suck in bottom-dwelling organisms or detritus armored mineralized bone, offered protection from predators

Mammals

other living lineage of amniotes named for distinctive mammary glands, produce milk for offspring characteristics: hair and fat layer under skin provide insulation that conserve water and protect body against extremes of heat or cold found in many terrestrial environments. adaptation for life on land is kidney - efficient conserving water when removing wastes from body kangaroo rats adept conserving water can survive in arid environments while drinking little or no water at all mammals are endothermic like birds most have high metabolic rate efficient respiratory and circulatory systems (4 chambered heart) support mammals metabolism larger brain than other vertebrates of equivalent size and shape capable learners teeth of reptiles generally uniform in size shape jaws of mammals variety of teeth sizes shapes adapted for chewing many kinds of food humans have teeth modified for shearing (incisor, canine) and crushing and grinding (premolars and molars) extant vertebrate taxa - mammals and reptiles are sister groups but evolved independently lineages diverged more than 300 million yrs ago Mammals originated group of amniotes called synapsides

This worm can be cut in half and regenerate so the result will be two organisms. earthworm - NO leech ascaris planaria**

planarian

Effects of Bilaterian Radiations 1 and 2

prior to radiations, ocean's large eukaryotes slow-moving and soft-bodied radiation of marine invertebrates began early Cambrian 535 million yrs ago, large invertebrate predators sharp claws appeared with diversity large, well-defended prey rise of aquatic vertebrates - excelled capturing food, avoided being eaten gnathostomes - jawed vertebrates originated 440 million yrs ago, dominant predators in oceans more than 400 million yrs resulted in paired fins, tail adaptations for swimming jaws adaptations for feeding

Dating the Origin of Bilaterians

radiation of bilaterians during the Cambrian explosion impact Earth molecular estimates suggest bilaterians evolved by 670 million years ago , 135 million years BEFORE Cambrian explosion oldest fossil bilaterian mollusc Kimberella lived 560 million years ago. Fossil evidence differs from molecular clock estimates by more than 100 million years eukaryotic lineages rise to lg organisms 600 million year old alga spines began to appear on outer surfaces

Amphibians

represented today 6150 species 3 clades" salamanders - clade Urodela "tailed ones" frogs - clade Anura "tailless ones" caecilians - clade Apoda "legless ones" live first in water during larval stage land as adults undergo metamorphosis typically as when gill-breathing tadpole lives in water transforms into lung-breathing frog lives on land some don't live dual land and water some salamanders only aquatic, other live on land as adults or whole life salamander that lives on land walks with side-to-side bending of body trait found in early terrestrial tetrapods Frogs suited moving on land than salamanders "toads" are frogs that have leathery skin or other adaptation for living on land caecilians - legless and nearly blind lack of legs secondary adaptation - evolved from legged ancestor Caecilians inhabit tropical areas - most species burrow in moist, forest soild Most amphibians found damp habitats swamps, rain forests those adapted to drier habitats - spend time in burrows or under moist leaves - humidity is high **one reason amphibians require relatively wet habitats - rely heavily on moist skin for gas exchange - if skin dries out = cannot get enough oxygen** typically lay eggs in water or moist environment on land, eggs lack shell and dehydrate quickly in dry air past 30 yrs zoologists documented rapid decline in amphibian populations in world causes:spread of disease-causing chytrid fungus, habitat loss, climate change, and pollution some declines = extinctions studies at least 9 amphibian species become extinct with last 4 decades more than 100 other species not observed in that time = extinct?

Reptiles

reptile clade: tuataras, lizards, snakes, turtles, crocodilians, birds 18,300 species reptiles majority are squamates (lizards and snakes) 7900 species or birds 10,000 species dinosaurs are reptiles birds originated from saurischian dinosaurs group includes T REX result - birds are reptiles fossil evidence earliest reptiles lived 310 million yrs ago resembled lizards share derived characters distinguish them from other tetrapods unlike amphibians = reptiles have scales contain protein keratin (like human nail) help protect animal's skin from desiccation and abrasion. most reptiles lay shelled eggs on land, shell protects egg from drying out, fertilization occurs internally before eggshell secreted lizards and snakes described as "cold-blooded" b/c don't use their metabolism extensively to control body temperature they do regulate body temperature through behavioral adaptations ex: bask in sun when air is cool, seek shade when air is warm more accurate description of these reptiles is they are Ectothermic - means they absorb external heat as their main source of body heat reptile clade not all ectothermic birds are endothermic - capable of maintaining body temperature through metabolic activity extant reptiles - 2 large clades - one includes tuataras and squamates (lizards and snakes) other - includes turtles, crocodilians, birds

Which of the following clades contains the greatest number of animal species? the vertebrates the bilaterians the deuterostomes the insects

the bilaterians

Mollusca

the molluscs - body 3 main parts: muscular foot usually used for movement, visceral mass containing most internal organs and mantle fold of tissue that drapes over visceral mass, secretes a shell if present molluscs serve present great diversity invertebrate bilaterians origin - Arthropoda

Which of the following was probably the LEAST important factor in bringing about the Cambrian explosion? -the emergence of predator-prey relationships among animals -the accumulation of sufficient atmospheric oxygen to support the more active metabolism of mobile animals -the movement of animals onto land -the origin of Hox genes and other genetic changes affecting the regulation of developmental genes

the movement of animals onto land

Evolutionary Radiations

two species that interact can exert selective pressures on one another a plant or another species that interacts with an animal may evolve in response to selection imposed by the animal; the animal in turn may evolve in response to selection imposed by the animal and the animal, in turn, may evolve in response to evolutionary changes in the plant.

Ecological Effects of Animals

until 600 million yrs ago, life in oceans almost all microscopic differences today: early marine communities no large suspension feeders (which remove food particles suspended in water) result, researchers think ocean waters cloudy, thick with microorganisms suspended organic matter geologic and fossil evidence suggests turbid waters low oxygen levels dominated by cyanobacteria marine ecosystems remained this condition over billion yrs despite fact algae and variety of heterotrophic eukaryotes present for most of the time

Ray-finned fishes - clade gnathostomes called Osteichthyes

vast majority vertebrates - clade gnathostomes called osteichthyans ossified (bony) endoskeleton, lungs or lung derivatives diversified two lineages - ray-finned fishes, lobe-fins ray-finned fishes named for bony rays support fins 27,000 species