bio 204 exam 3
What does the word gnathostome mean?
"Jaw Mouth" => vertebrates with jaws
There are multiple causes for amphibian population crashes and species extinctions - what are these? One cause is particularly problematic - what is this problem? Remember that we talked about it previously.
"Standard" problems: 1. Habitat destruction 2. Over-exploitation Other Factors: 1. Introduced species (e.g., mountain yellow-legged frogs impacted by introduced trout in CA) 2. Climate change, including increased UV-B radiation 3. Water pollutants- Very Problematic!!! 4. Emerging infectious diseases => chytrid fungus
What is the sixth sense that some snakes have evolved (such as pit vipers)?
"heat detecting organs between eyes and nostrils of pit vipers are sensitive to minute temperature changes, enabling night hunters to locate warm animals" pg. 717 Pits on the face house receptors that detect infrared heat
Define parasitism. Your friend tells you that parasites are lowly animals, barely evolved. You respond, "nope", parasites are actually very successful, for the following reasons .......
-+/- ecological interaction => Parasites benefit at expense of host, typically NOT killing host as single individuals -Parasites live inside (endoparasites), or attached to outer surface (ectoparasites) of animal host body, obtain nutrients from host -Parasites are NOT 'degenerate' animals, but rather, highly-specialized for a unique lifestyle -Basically, ALL animals serve as hosts for one or more parasites - yes, this includes humans
What are the 4 stages of complete metamorphosis? Why is a different larval stage an advantage?
-Egg >> larva >> pupa >> adult stages - Advantage: Don't have to compete for food image in study guide
What are the "local" and "global" threats to coral reefs?
1) "Local" threats Land-based pollution (chemicals & sedimentation), mining and "blast" fishing 2) Water is too warm Photosynthetic dinoflagellates are expelled, corals "bleach" 3) Declining ocean pH associated with increased atmospheric CO2 Calcification (corals + others) decreases as oceans become more acidic
Arthropods are the most successful animal group - what are some reasons we can say that?
1) Ecological Diversity - in essentially all habitats >> aquatic + dominant life form on land & in the air 2) Numerically Dominant Metazoans - some estimates suggest a billion, billion individuals 3) Species Diversity - 2/3rd of all described animals; ~1 million species described
Why do we consider Animal Parasites Successful?
1) Essentially all animal groups include some parasitic representatives (lifestyle has evolved many times independently from nonparasitic ancestry) 2) Perhaps 1/2?? of all animal species are parasites!! (numbers skewed by mega-diverse groups, e.g., nematodes, parasitic wasps, etc..)
Cephalopods are intelligent animals - give three examples of such intelligence.
1) Use tools for defense 2) Can solve problems 3) Show long-term memory 4) Can recognize individual conspecifics 5) Can recognize human caretakers 6) Complex social communication
Name 4 major anatomical changes that occur in the transition from tadpole to adult frog?
1) loss of gills 2) formation of limbs 3) loss of tail 4) change of digestive system
Three genomic processes have resulted in the HOX gene differences observed between Protostomes and Deuterostomes - what are these processes??
1.) Duplication of genes on a single chromosome => results in "family" of related genes ("gene birth") 2.) Two-fold Whole genome duplication in early-diverging deuterostomes 3.) Some genes lose functionality because of functional redundancy ("gene death")
What are the two keys for spider success?
2 "Keys" to Spider Predation & Success: Silks and Venoms
What is the triploblastic condition? What are the ultimate developmental fates of the three individual triploblastic germ cell layers in Bilaterians?
3 EGCLs = endoderm, ectoderm, mesoderm; these germ layers develop into specific adult tissues/organs: ectoderm - outer body covering, nervous system endoderm - gut lining, liver, lungs mesoderm - true muscle tissue, bone, connective tissues, etc.
What is the basic body plan of an insect?
3-part body plan as adults => head, thorax, & abdomen 3 pairs of legs arising from thorax (= hexapod)
Genes are often duplicated in genomes (i.e., a single gene gives rises to two "daughter" genes through duplication of a chromosome or part of a chromosome). What are the three possible fates of such duplicated genes?
A) Lose functionality (pseudogene), go "extinct" B) Neofunctionalization - evolve a "new function" different from ancestral gene C) Subfunctionalization - two "daughter" genes each take on part of function of "mother" gene
What are the two primary groups of living tetrapods? (Tetrapoda=4 limbed vertebrates)
Amphibians Amniotes (Reptiles, Birds, and Mammals)
Discuss the colonial body organization of Physalia.
An individual is actually a colonial animal made of physiologically-connected 2N zooids/individual animals, all derived from a single zooid via budding
Where did the animal kingdom originate? Why might this be important?
Animal Life began in Oceans The majority of the major animal groups remain marine A handful of animal clades have invaded Land, 2 groups are particularly successful on Land => (Arthropods and Vertebrates) Some have returned back to oceans
What characteristics unite and describe animals?
Animals are multicellular, heterotrophic eukaryotes that ingest food items (unlike fungi, which absorb their food), with tissues that develop from embryonic germ layers Cellular specialization Collagen
What do both confirm, however?
Animals have a very DEEP history on Earth
What is the ECM and why is it important?
Animals have extracellular matrix (ECM) while plants have Cells walls, Primary components include glycoproteins (most important = collagen) and proteoglycans (small protein core + linked carbohydrate chains) Holds cells together in tissues, adds structural support, acts as a filter, involved in cell communication Cell communication & coordination very important in multicellular organisms
Besides earthworms, what organisms are in Annelida? Where is much of the diversity found? ( where is the answer to this question)
Annelida = "little rings" Segmented worms include marine, freshwater and terrestrial species Errantians (errant = traveling) are marine group. Include mobile predators, algae grazers and large tube-dwellers. Some have parapodia on each segment that aid in locomotion Sedentarians (sedere = to sit) burrowers and tube-dwellers Christmas tree worm has elaborate gills - gas exchange and feeding
When was the Cambrian explosion, and why is it of interest?
Around 530 MYA Major Point of Diversification -Fossils representing around half of extant -Animal groups appear suddenly -Much diversification over a very short geologic time span -Most fossils from cambrian explosion are ---Bilaterian
About when did arthropods invade land?
Arthropods = first animals to invade land, ~ 420 MYA
What does the cuticle help form in arthropods?
Arthropods Only - chitinous cuticle functions as external skeleton (= exoskeleton)
Be able to describe the mimicry seen with coral snakes
Batesian mimicry: harmless species evolve coloration/pattern/behavior that mimics the harmful species (model) many harmless species have evolved coloration/pattern that mimics that of coral snakes mimicry is common in North and South america
What groups are in the clade Archosauria? What similarities do crocodilians share with their closest living relatives?
Birds, Dinosaurs, and Crocodilians Similarities between birds and crocodilians 1. Four chambered heart 2. Vocalize or "sing" during breeding season 3. Build and guard nests for their eggs
What is a "body plan"?
Body Plan = a description of the overall system of body organization important features: symmetry, tissue complexity, with or w/o appendages, segmentation
Ctenophore/comb jellies: how are they similar to jellyfish? How are they different?
Both are transparent, mostly water, and carnivores Different in that comb jellies have: -Two openings (mouth and anus) -Medusa with eight "combs" of cilia - move -Planktonic predators, acquire prey w/ sticky threads
Different ways turtles breathe?
Breath through buccal pumping Abdominal muscles used similar to mammalian diaphragm
What incredible talent does the Fitzroy River Turtle from Australia have?
Bum breathing: water pumped in and out of cloaca -Gas exchanged via vascularized bursae
What famous fossil assemblage has diverse and dominant arthropods?
Cambrian Explosion fauna
Cephalopods have a camera-lens type eye. This type of eye is said to have evolved convergently in cephalopods and vertebrates - what does this mean??
Camera-lens Eye in some Cephalopods - functionally very similar to vertebrate eye, evolved independently (example of convergent evolution)
Why is the shape of their cells important phylogenetically?
Cells are very similar to collar-cells (choanocytes) of sponges
What are two primary features that suggest a relatively early phylogenetic divergence for Sponges?
Cellular Grade of Organization (GoO) -LACK true embryological germ cell layers (EGCLS) -LACK adult tissue layers (contrasts with TISSUE GoO all other animals) More cell individuality than typical cells in remaining animals -Some cells mobile -Cell differentiation is reversible (amoebocytes in particular)
What are the four main groups of living arthropods?
Chelicerata Crustacea Myriapoda Hexapoda
What is the closest single-celled relative of animals? What do they look like?
Choanoflagellates (small, aquatic flagellates, funnel-shaped collar)
What are the big four insect orders?
Coleoptera (beetles) Lepidoptera (moths, butterflies) Hymenoptera (bees, wasps, ants) Diptera (true flies)
What are conotoxins? How has conotoxin diversity evolved?
Cone Snails (Conus) - marine gastropods Diverse, mostly tropical genus (~ 700 species) Predators, feeding on worms, other snails, fish Radula modified as venom-delivering 'harpoon", potential speeds of 200 m/sec!! Cone Snail Toxins (Conotoxins) Peptides (small 10-40 AA proteins) isolated from Conus Any single species produces a "venom cocktail" including many small peptides (up to 200 different peptide molecules) Each conotoxin is targeted to very specific cell receptor targets (mostly ion channels) Different genes (peptides) in same "gene family" = evolved via gene duplication, allowing evolution of new peptide functions!!
Why are crustaceans so important in marine environments?
Copepods - planktonic among most numerous of all animals Algae grazers Shrimp-like krill also abundant
What are coral reefs? Why are coral reefs both economically & ecologically valuable - at least 3 reasons?
Coral Reefs, reef building corals (colonial Anthozoans) with calcium carbonate skeletons formed from symbiosis with photosynthetic dinoflagellates. Structural Complexity a KEY reason for diversity Corals - some hydrozoans, mostly anthozoans Econ/Ecol valuable: 1.) Hold high diversity of organisms 2.) Extremely rich biologically ("Rainforests of the Sea") 3.) A lot of different niches in a coral reef 4.) Support a number of human economic activities
How do choanocytes work, and how are these cells fundamental to the sponge design? What role do choanocytes play in sponge reproduction?
Create water currents and trap microscopic food particles/gametes; also involved in egg & sperm production Choanocytes give up sperm to the egg
Do the cuticles of nematodes act as an "exoskeleton"?
Cuticular integument NOT acting as external skeleton (hydroskeleton)
Modern birds radiated ~ 65 million years ago. What major biotic changes were happening on Earth at about this time?
Dinosaurs went extinct [K-T Extinction Event]
Modern mammals radiated ~ 65 million years ago. What major biotic changes were happening on Earth at about this time?
Dinosaurs went extinct [K-T Extinction Event]
Define diploblastic. What are the two embryonic germ cell layers in diploblasts, and which tissue layers do these give rise to in Cnidaria?
Diploblastic: two EGCLs (ectoderm and endoderm) which give rise to specific adult tissues: Endoderm => forms adult gastrodermis Ectoderm => forms adult epidermis
What morphological feature unites the clade Ecdysozoa?
Ecdysozoans = "molting animals" - protein-based outer body covering (cuticle) that is periodically molted for growth (= Ecdysis) Several groups with worm-like body plans (e.g., nematode worms, kinorhynchs, nematomorphs, etc.) Lack appendages, mostly marine, fluid-based skeleton
Define endothermy.
Endothermy=have a body temperature principally dependent on internally generated metabolic heat Ex. small birds and mammals
The ray-finned fish epidermis has multiple functions - what are these?
Epidermal glands secrete " mucous " -Reduces drag -Provides protection from pathogens -Nearly "watertight" - barrier to water gain/loss
Did gnathostome lungs evolve on land, or in aquatic habitats? What is the evolutionary fate of lungs in some Ray-finned fishes? How do these animals thus respire?
First evolved in fishes -preceded evolution of terrestrial tetrapods by millions of years!! Initially evolved as evaginations of the pharyngeal region of the digestive tract
Describe and define the function of the lateral line system (LLS), and of the Ampullae of Lorenzini.
For mechanoreception (detecting low frequency vibrations in water) => e.g., water movements caused by struggling fish Extremely sensitive hair cells that respond to water displacement LLS also found in ray-finned fishes, lobe-finned fishes, and aquatic amphibians => general system for mechanoreception in aquatic gnathostomes Sharks & rays detect electrical fields that accompany muscle contractions of prey items!! Can also use electroreceptors to detect small differences in water temperature => used for navigation (water currents), finding prey that prefer certain water temperatures, etc... (*Ampullae of Lorenzini - sensitive electroreceptors)
Why are fossils and molecular clocks in disagreement over the age of animals?
Fossil records are incomplete and Molecular clocks (which are calculated through genes + phylogeny + fossil calibrations) may not be accurate models
When did tetrapod terrestrial invasions occur? Were tetrapods the first animals onto land?
Fossils suggest late Devonian invasions (360-380 MYA) No, plants/other animals were already on land before tetrapods
Recall the four key chordate characters. These characters evolve into different structures with different functions in derived chordates - give an example using the pharyngeal gill slits.
Four key chordate characters 1.) Dorsal, hollow nerve cord 2.) Notochord Fibrous, supportive rod extending length of body beneath dorsal nerve cord 3.) Pharyngeal slits or clefts Allow water to bypass digestive tract Suspension-feeding devices in invertebrate chordates 4.) Muscular, post-anal tail see study guide image
Birds are actually feathered theropod dinosaurs - did feathers originally evolve for flight, or for other functions? What were these possible functions?
Function of early feathers: -thermoregulation (retaining body heat) -social displays -NOT flight
Summarize the species and ecological diversity of molluscs. What are the 3 major groups of molluscs, with examples of each?
Gastropoda (Snails, slugs) Bivalvia (clams, mussels, scallops, oysters) Cephalopoda (squids, octopuses, cuttlefishes)
What is the function of the gastrovascular cavity (GV cavity) in Cnidarians? How does this function relate to basic cellular requirements (i.e., nutrition, respiration, etc)?
Gastrovascular Cavity extends throughout body -functions as simple transport system for exchange of food items, gases, wastes Single oral opening leads to blind gut => Gastrovascular Cavity GV cavity sometimes greatly subdivided (e.g., extends into tentacles) All cells of body in contact with GV fluids or external medium
What kind of data have established the sister group to turtles? What clade are they sister to?
Genomic data establish this phylogenetic relationship Sisters to Archosaurs
Explain how the countercurrent exchange mechanism allows fish to extract oxygen from the water as it flows over their gills.
Gills protected by a bony operculum Used alone, or in combination with lungs see study guide image
Vertebrates are said to be morphologically disparate - what does this mean?
Great variation in morphological form despite relatively limited species diversity As an example, contrast this with beetles => HUGE number of species, limited diversity in form
What are HOX genes, and why are they important to animals?
HOX genes => highly conserved developmental regulatory genes Possessed by all metazoans Control body plan/regulate body formation during development Unique to animals Important because they play important roles in the development of animal embryos, controlling the expression of many other genes that influence morphology
Describe the amniote egg, including functions of the four extraembryonic membranes. Why does the amniote egg further facilitate life on land?
Has 4 extraembryonic membranes, 3 unique to Amniotes -Amnion: Surrounds embryo in fluid- filled cavity; cushioning & preventing dehydration -Allantois: Extends from hind gut; Storage of metabolic waste products, aids in gas exchange -Chorion: Outer-most membrane; involved in gas exchange -Yolk Sac: includes yolk, providing nutrients see study guide image
Modern birds show tremendous diet breadth - give examples of particulate feeders, herbivores, carnivores, and scavengers. Common names will suffice.
Herbivores: -Macaw, MALLARD Carnivores -Heron, Eagle, Scavengers -vultures
Living mammals have two defining features that actually evolved in earlier synapsid ancestors - what are these?
Heterodont dentition Jaw-articulation moves to dentary squamosal (3 boned middle ear)
Living birds are a special type of dinosaur called the theropod dinosaurs - what features do living birds share in common with extinct theropod dinosaurs?
Hollow, pneumatic bones Elongate, moveable, S-shaped neck Tridactyl foot (3 toes forwards, one back) Collagen (protein) similarities!
Define homeothermy
Homeothermy=Maintains a relatively constant internal body temperature regardless of external influences Ex. Fish
Contrast homodont dentition to a heterodont dentition.
Homodont=Teeth are not specialized - look/shaped the same way Heterodont=Teeth becoming more specialized - think human teeth (molars, incisors, canines)
What are the 5 keys to insect success as a group? Understand each one
I) Complex senses of vision, hearing, olfaction, touch, etc.. Pollination (finding flowers), sexual interactions (finding conspecific mates), parasitism (finding hosts) => all require complex sensory systems 2) Possess wings (only invert animals with wings) Insects first animals to evolve ability to fly restricted to adult insects NOT appendages - cuticular extensions of dorsal thorax => unlike flying vertebrates, do NOT forfeit functionality of appendages to fly!!! Most (not all) adult insects with 2 pairs of wings (on middle & hind segments of thorax) Fore-wing (Mesothorax) Hind-wing (Metathorax) Best fliers actually only use a single functional pair of wings Of course, flight is advantageous: escaping predators colonizing new regions, habitats move efficiently to patchy resources (e.g., water sources, other animals, plants, flowers) 3) co-Diversification with plants (e.g., pollination, plant-feeding) Pollination is (usually) a +/+ ecological interaction Mutualism - both parties benefit, evolve codependence Plants receive fertilization services, insects rewarded with nutrient-rich nectars & pollen 4) Most diverse groups (but NOT all insects) with Complete Metamorphosis: Egg >> larva >> pupa >> adult stages Some, but not all insects, have Complete Metamorphosis involves a major morphological change during development (larvae vs. pupae vs. adult) Two implications of Complete Metamorphosis: I) Major morphological change implies major ecological difference between life stages (= reduced competition among life stages) II) Pupal stage can evade harsh seasonal conditions, populations can rapidly respond to resource availability The "Big 4" ALL exhibit complete metamorphosis - again, partly responsible for success of these groups 5) Many are Parasites Many Insects are Parasites (Using other animals as food resource) Many insects are parasites of other insects e.g., huge diversity of LEPIDOPTERAN larvae (caterpillars) These caterpillars comprise large resource for parasitic wasps
Tetrapods ultimately evolved to be land animals. What characters already possessed by tetrapod ancestors facilitated this transition to land?
I. Bony Endoskeleton -system of body support in a non-supportive environment II. Lungs (*gills don't work on land!) -primitive feature for Bony-fishes (Osteichthyes) III. Pectoral & pelvic girdles, with associated ---limbs + terminal phalanges => -obviously important in land-based locomotion
What is the role of cadherin?
Important in cell-cell adhesion => key to evolution of multicellularity
What is a placoderm? "Plate Skin"
In fossil record from Silurian (~440 MYA) to Devonian (~360 MYA) Represented by 200 described genera!! Heavily armored head region (lots of dermal bone) With jaws, but LACKING teeth (*implies "jaws first" evolution in gnathostomes)
Where are most crustacean species found?
Includes crabs, lobsters, shrimp, woodlice, and more 67,000 described species Most are marine (freshwater, terrestrial)
What's so interesting about comb jellies pooping?
It does not come out of their mouth, which allows them to be more complex and to eat while digesting
Why is Tiktaalik an important fossil tetrapod - i.e., what does this fossil tell us about tetrapod evolution?
It's a fish with wrists
Why are gnathostomes successful?
Jaws (& Teeth) - grasp, manipulate, shear food objects => New food resources become available Unpaired + paired fins => better, faster, more maneuverable swimmers
Jaws evolved from which structures in more early-diverging Vertebrates? What is the evidence for this homology?
Jaws evolved from anterior pharyngeal arches of early-diverging vertebrates Evidence for Gill Rod - Jaw Homology 1) Position on body (positional homology) 2) Both structures derived during development from neural crest cells 3) Nerve distribution to associated muscles is similar
What are key structural proteins in the amniote integument? Give three examples of epidermal structures that are mostly comprised of these key proteins. How do these structures further facilitate life on land?
Keratins: they replace all/most metabolically active cytoplasm Keratinized cells are resistant to abrasion and water loss Keratinized cells form: -Skin covering -Mammal hair -Hair derivatives (claws, hooves) -Scales -Feathers
Which of the big four has many parasitic species whose hosts are other arthropods?
LEPIDOPTERAN larvae (caterpillars) comprise large resource for parasitic wasps
How is hair related to the evolution of lactation?
Lactation likely developed from glandular secretions associated with hairs
What are some well-known parasitic annelids?
Leeches - mostly freshwater (a few marine, a few terrestrial) Invertebrate predators and blood suckers (Release and anesthetic and anticoagulant)
Why are modern coelocanths considered "living fossils"? What are general characteristics of "living fossils"?
Living Fossil: A living (extant) species representing a group that was previously more diverse, and has a well-known fossil record (e.g., sturgeon) -Typically exhibit slow rates of morphological evolution --living species surprisingly similar in morphology to fossil species Coelacanths (living genus Latimeria) -Two species --Fossils in same lineage range from 400-75 MYA, representing 125 different species!!
Living mammals represent a prime example of an adaptive radiation. What are some aspects of this radiation?
Living mammals found in terrestrial, freshwater, oceanic habitats Blue whale versus a bat Diverse modes of locomotion Diverse in diets
Why can't shark populations quickly rebound after over-harvesting - at least three reasons?
Long Age to maturity Small Litter size Biennial reproductive frequency Gestation period of 9-24 months
Why is pollination such a valuable ecosystem service?
Majority of flowering plants depend upon insects for pollination => essentially all terrestrial ecosystems would collapse without this interaction; this includes Agroecosystems One of the most important Ecosystem Services on Earth
Birds evolved the ability of powered flight from terrestrial flightless ancestors that possessed features facilitating this transition - what are these features?
Many features associated with flight evolved before flight- facilitated the evolution of flight in birds: -Feathers -Endothermy -Hollow bones -Long forelimbs
What are some of the specialized appendages found in crustaceans?
Many specialized appendages: antennae, mouthparts, walking legs, feeding legs, swimming legs
Why are silk proteins of interest for human technology?
Many spider silks outperform other natural & man-made materials (e.g., steel, Kevlar, elastin, etc.) Considerable interest in silks as strong, stretchy, light-weight, biodegradable, hypoallergenic biomaterials Military uses => parachute cords, aircraft materials, bullet-proof vests, etc. Biomedical uses => artificial ligaments, wound dressings, microsutures, scaffolds for tissue growth, etc.
Describe the research looking at "hookworm soup" and remember this is a nematode
May alleviate symptoms of autoimmune diseases Anti-inflammatory protein-2 from worm soup Maybe parasites aren't always the "enemy"
A phylogeny of Cnidaria helps to explain the distribution of polyp + medusa across the major Cnidarian groups. Explain.
Medusa stage likely evolved to facilitate outcrossing + dispersal in open ocean Anthozoa (most left) never developed medusa stage Cubozoa and Scyphozoa (Middle) have reduced polyp Some Hydrozoa lose polyp
How are animals related to other multicellular eukaryotes? (3 Ways)
Membrane bound nucleus Membrane bound organelles Linear DNA
What are the two groups of myriapods and what are a couple differences?
Millipede -Some of the oldest land animals -Detritivores -Each segment has two pairs of legs -Chemical defenses Centipede -Carnivores -Each segment has one pair of legs -Claws that paralyze prey ("fangs" with venom)
When we think of animals, we often think of fellow vertebrates but most animals are what?
Most (34 of 35 groups) comprise INVERTEBRATE ANIMALS!!! A single group (Chordates) includes the Vertebrate Animals
What have made these groups so successful?
Most insects (and thus most animals) are members of the "Big 4" - partly successful because these taxa use flowers as resources
What are neural crest cells? What are important cell derivatives of neural crest cells? Also use an example from an adult vertebrate.
Neural Crest cells - population of multipotent, migratory developmental cells arising from top margin of neural tube (derived from ectoderm) Neural Crest cells important in head structures Also migrate from neural tube along entire body axis => differentiate into important cells/structures along entire body axis Neural cell derivatives: -Peripheral nervous system -Facial cartilage & bone -Pigment cells see study guide image
Are horseshoe crabs crustaceans? Why are they of interest in biotechnology?
No, horseshoe crabs are Chelicerata Chelicerata also includes: Pycnogonids (sea-spiders) Arachnids (scorpions, spiders, mites, etc) They are of interest in biotech because we use them in the medical field for the LAL test (or Limulus amebocyte lysate) Coagulogen in blood cells Worth $15,000 per quart Forms a gel when it encounters endotoxins Lipoglycans from cell wall of Gram-negative bacteria Can detect concentrations of one part per trillion
What are key vertebrate features/innovations?
Notochord ➨ reduced in most Vertebrates (e.g., remnant intervertebral discs in adult humans) Dorsal hollow nerve cord ➨ Spinal cord plus brain Pharyngeal slits (and supporting arches) ➨ respiration in aquatic vertebrates (gills) or jaws in jawed vertebrates
Why is their colonial nature important phylogenetically?
Often live as colonies - show some cellular specialization (different cell types doing different things) - 'animal-like' in this respect
Archaeopteryx is an evolutionary "mosaic" - showing both modern bird-like features, and ancestral "reptilian" features. Provide examples of each. Why is such evolutionary "mosaicism" expected?
One of First true birds due -Furcula (wishbone) -Long forelimbs with winglike proportions -Asymmetric vaned feathers Retained "Reptilian" features: -Beak with Teeth -Long tail with many vertebrae
What are three main innovations defining Bilateria?
Organ Systems (primary four - digestive, respiratory, excretory, linked by circulatory) Bilateral Symmetry and Cephalization (= concentration of feeding organs, sensory and neural structures at the anterior end of body) Triploblastic => 3 EGCLs
Why is the chitin-based exoskeleton a key to arthropod success?
Outer waxy layer retains water (*water conservation one of the primary keys to success on land) Strong, but lightweight material (a supportive skeleton that also allows great mobility) Varies from very hard to very flexible (flexible joints are KEY to movement)
Know the three primary geological Eras, including absolutes times that divide these eras.
Paleozoic Era (Carboniferous, Permian) Mesozoic Era (Triassic, Jurassic, Cretaceous) Cenozoic Era (Tertiary to present)
Multiple groups of tetrapods have convergently evolved the ability to glide - provide examples. Multiple groups of tetrapods have convergently evolved the ability of powered flight - provide examples.
Parachuting and/or gliding: -Some frogs, lizards & snakes -Some non-bat mammals Powered flight - Three independent derivations -Pterosaurs (extinct), birds, bats
How are teeth in Chondrichthyes related to placoid scales? How do shark teeth differ from the teeth of other Gnathostomes?
Placoid Scales - mineralized dermal tissues Chondrichthyes (shark) teeth form from skin as whorls => rest ON jawbone Other gnathostomes with teeth embedded into jawbones => different developmental origin
What are the three primary cell types found in sponges, and what are their specific functions?
Porocytes - cells surrounding pore openings (ostia) Amoebocytes - food transport thru mesophyll, structural support (e.g., producing spicules) Choanocytes (collar cells): Engulf bacteria and other food particles by phagocytosis create water currents and trap microscopic food particles/gametes; also involved pin egg & sperm production
Provide details of one example of a conotoxin that has been developed as a drug - e.g., how does the drug work? Why is the drug a nice alternative to morphine?
Prialt (Primary alternative to morphine) => non-addictive, anti-tolerance treatment for severe chronic pain => selectively blocks voltage-gated calcium channels (which propagate action potentials)
What is a primary function for hair? What are other, secondary functions? Why aren't most marine mammals (e.g., whales & dolphins) hairy??
Primary function: -provides insulation (traps thin layer of air above integument) -prevents heat dissipation from body to the environment, prevents absorption of heat from the environment Secondary functions: -impart color, sensory structures, protection Marine mammals have no hair because it's more hydrodynamic
Remember what major group do water bears belong in?
Protostomia -> Ecdysozoa -> Panarthropoda -> *Tardigrades*
There are a large number of terrestrial, lungless salamanders. Why are there no lungless lizards?
Salamanders can breath through their skin (can't remember word for it will update when slides are posted-cutaneous respiration!), lizards cannot
What do genomic analyses reveal about the origin of animals?
Same Reveals animals share a single common ancestor Evidence suggests that animals form a monophyletic-clade: METAZOA
Talk about the global distribution, prevalence, and impact of Schistosomiasis in humans?
Schistosoma trematodes are very harmful to humanity => Schistosomiasis (also called Bilharzia) 3 species in the genus Schistosoma: distributed in tropical countries worldwide => so-called "neglected tropical disease" Causes chronic illness or liver/kidney damage (symptoms in response to egg deposition), ~ 20 million humans severely ill, with over 200 million people infected worldwide (CDC 2015 numbers)
What is a turtle shell made from? What are some anatomical modifications that evolution of a shell required?
Scutes composed of dermal tissue Broadening of the ribs Encapsulation of the shoulder blade (scapula) within the shell Fusion of vertebrae and clavicle to shell
Why are barnacles such odd crustaceans?
Sessile adults but mobile larvae Natural adhesive very strong Shell hardened w/ calcium carbonate
What is significant about proteins found in the choanoflagellate genome?
Shared parts of genome include proteins for cell signaling and cell adhesion previously thought to be restricted to animals Cadherin protein found both in Choanoflagellates and Animals => "CCD" (cytoplasmic cadherin domain) domain found only in animals
Amphibians are either "tied to water" (i.e., must have water to complete part of their lifecycle), or found in moist terrestrial habitats. What aspects of amphibian biology impose these constraints?
Skin - thin permeable skin LACKING scales - permeable to respiratory gases (many taxa with cutaneous respiration) thin, permeable skin implies desiccation in dry habitats eggs covered with a jelly-like substance, no protective shell, need to be in a pond or river
What are three skull characteristics of an early-diverging synapsid (like Dimetrodon)?
Skull w/ single temporal fenestra Jaw articulation formed by articular quadrate bones (~Homodont dentition) Along w/ reptiles, each independently evolved:
What is the most successful clade of Lepidosaurs? What unique adaptations have helped them?
Snakes are most successful "Lizards" Jaw morphology allows them to eat large prey Dietary specialization Venom also an important innovation Venom: toxin delivered via fangs
What is the function of cnidocytes and nematocysts? What is the mechanism of nematocyst discharge in Hydra cnidarians?
Specialized cells (cnidocytes) fundamental to predatory lifestyle; most cnidocytes house stinging organelles called nematocysts Nematocysts = organelles, enclosed in cnidocyte cells Chemical/Mechanical stimulation causes nematocyst to "fire" => threads, coils, toxins subdue prey How Nematocysts Discharge in Hydra: -Recent research suggests a combination of osmotic pressure (calcium ions moved from nematocyst capsule into cell cytoplasm), plus energy stored in collagen proteins of capsule wall
What are some of the different ways spiders use silk?
Spider Silks are Produced in Abdominal Silk Glands => produced as liquid proteins Some spiders have several gland types, each producing silk proteins with different functional properties, used in different ways!! The Many Functions of Spider Silks: Egg sacs/Nests Silken "balloons" to aid in Dispersal Burrow Protection (e.g., trapdoors) - antifungal properties, concealment, mechanical protection from predators "Spider webs" - silken constructs used to detect, capture & hold, wrap prey (mostly insects)
Why can't we raise spiders for their silk like we do silkworms?
Spiders are predators!! Liquid protein to solid silken fiber transition difficult to replicate
What are some important lineages within Arachnida?
Spiders, Scorpions, Harvestmen, Solifugae, Schizomids
Schistosoma flukes have three cellular/molecular mechanisms that prevent detection by the host immune system - what are these mechanisms?
The adult Schistosome tegument => key to success, but also potential Achilles heel Outer body wall = single syncytium (also called distal cytoplasm, DC) Evading Detection by Host Immune System: I) Mask surface with host proteins => "immune masking" II) Syncytium is NOT a static layer, undergoes frequent transformation III) Very few parasite proteins expressed exclusively in wall of tegument (=> few targets for host immune response)
Why are tardigrades amazing, and what specific gene did we talk about?
The most resilient animal known, surviving extreme conditions that would be rapidly fatal to nearly all other known life forms Withstand EXTREME temperatures Extreme pressure Ionizing radiation Vacuum of space No food or water for decades - near complete dehydration] Contain a protective protein that provides resistance to damaging X-rays • Researchers were able to transfer that resistance to human cells • Damage suppressor protein: Dsup
What are some insect ectoparasites that humans deal with?
Ticks Known as "Acari" (includes Ticks and Mites)-+
What are the arachnid ectoparasites that humans deal with?
Ticks - ectoparasites, vector for Lyme disease (spirochete bacteria) Mites - generally quite small Diverse, live in all habitats Detritivores, parasites
What does the clade Pancrustacea refer to?
Traditional "Crustaceans" not monophyletic: includes Hexapoda and hence Insecta also Remember, much of animal life traces to aquatic environments
What is the defining feature for Eumetazoan animals?
True tissues => derived from embryonic germ cell layers (EGCLs) Ex: Cnidaria - jellyfish, corals, relatives
Why are sea squirts (tunicates) strange chordates?
Tunicates (sea squirts) - chordate characteristics seen in larval stage -Incurrent siphon to mouth (big) -Excurrent siphon (small) -Pharynx with slits see study guide image
Modern birds are classified into two main groups - what are these, and how do these groups differ (in at least one character)? Which group of birds would you expect to be larger in size (on average) - why?
Two main groups: Palaeognathae (Flightless birds) and Neognathae (flight) -Neognathae: --have keeled sternum for flight muscle attachment --Pectoralis muscle works antagonistically w/ supracoracoideus muscle -Paleognathae (Ratite Birds) = Flightless birds --Flat sternum (no keel) --Few living species => Ostrich (Africa), Rhea & tinamous (S. America), Emu (Australia), Kiwi (New Zealand), Cassowary (New Guinea, Australia) --Larger in size, don't need to fly need to be faster, have longer legs
Explain how molecular phylogenetics links extinct theropod dinosaurs with living birds?
Tyrannosaurus collagen proteins derived from fossil specimens ~ 68 million years old!! Molecular phylogeny based on collagen protein sequences
What are some of the ecological reasons that tetrapods may have invaded land?
Unexploited food resources on land Very little competition on land Many predators in water
What organisms are echinoderms?
Unique water vascular system -Tube feet: locomotion & feeding Important members bilateral symmetry); Ophiuroids (Brittle Stars); Echinoidea (Sea Urchins); Sand marine communities Impressive regenerative properties Organisms include: -Asteroidea (Sea stars and sea lilies) - "Radial" symmetry (Re-evolved from Dollars; and Holothuroidea (Sea Cucumbers)
Most (not all) molluscs share 3 primary features in common. What are these? What are possible functions of these primary features?
Ventral Muscular Foot (used for locomotion, as holdfast, for feeding) "Visceral Mass" - houses internal organs (Primary Four organ systems typically present) Dorsal Mantle - cell layer that secretes shell - protects against predators, prevents mechanical damage, prevents desiccation (*when terrestrial)
How many times do we know viviparity (live birth) evolved in mammals? Contrast that with how many times it has evolved within living Lepidosaurs
Viviparity evolved one time in mammals Within the living lepidosaurs, it has evolved 110 times within snakes/lizards
What are some primary characters of Chondrichthyes? (which includes Elasmobranchii which includes sharks)
Well developed paired fins and toothed jaw Countercurrent gill respiration (posterior pharyngeal arches retain gas exchange function) Placoid scales Mostly cartilaginous endoskeleton Large,oily livers aid in buoyancy(*lack swim bladders) Ancestral gnathostomes hypothesized to have endochronal bone (= mineralized bony tissue that replaces cartilaginous connective tissue during development) Chondrichthyes lack endochronal bone, possess mostly cartilaginous endoskeletons with areas of superficial mineralization => condition is derived, NOT primitive
What is wing coupling? How does that relate to being an acrobatic flier?
Wing Coupling - wings hooked together, function as single unit (e.g., Hymenoptera, bees & wasps - good fliers) True Flies (Diptera) with only a single pair of wings => most acrobatic of insect fliers
What other structure are made of chitin cuticle?
Wings Cuticular Lenses Membranes for hearing Cuticular structures for producing sound
What is the cuticle of arthropods and relatives made of?
cuticle with structural polysaccharide chitin
Other mammal species have greatly impacted human history. Provide three examples.
dog horses farm animals Rats
Be able to draw a "generic" mollusc, with the four primary organ systems.
see study guide image
Draw a phylogeny with the following clades of living mammals placed correctly: Monotremes, Therians, Marsupials, Eutherians. With primary defining features for these clades.
see study guide image
Draw a phylogenetic tree that includes the following groups, with correct placements: Porifera, Eumetazoa, Cnidaria, Bilateria, Lophotrochozoa, Ecdysozoa, Deuterostomia (see Fig 33.2)
see study guide image -Porifera -eumetazoa: --cnidaria --bilateria: ------lophotrochozoa ------ecdysozoa ------dueterostomia
What three groups are deuterostomes?
see study guide image Chordata, Echinodermata, Hemichordata
Contrast and draw the two diploid morphological types found in Cnidaria: polyp versus medusa.
see study guide image Many Cnidarians alternate between two very different diploid morphologies in single lifecycle: polyp and medusa stages Polyp - oral side up, typically sessile, benthic habitats can produce new individuals via asexual budding; in few taxa, polyps are sexual (= producing haploid gametes) often colonial - many connected individuals produced by asexual budding - e.g. colonial corals Medusa - oral side down (not always!), free-floating, pelagic habitats (= open ocean) - sexual (producing haploid gametes) - e.g., most jellyfish
What are the primary differences between Deuterostomes vs Protostomes? - remember the Table of differences.
see study guide image Protostomes vs Deuterostomes: differ in following major ways.... 1) Position of Nervous System 2) Gene Duplication in HOX Gene Family 3) Fate of Blastopore (= first opening of future gut during embryonic development*)
Be able to draw the general lifecycle of a hydrozoan polyp, including relationships of the polyp, medusa, and larval stages. Do the same for a scyphozoan jellyfish.
see study guide image Scyphozoans (image below) - medusa most conspicuous lifestage, short-lived polyps produce more medusae
Describe and illustrate the complex lifecycle of a Schistosoma fluke. What is the biological significance of larval stages that use intermediate hosts?
see study guide image -Trematodes (flukes): Vertebrate Animal Endoparasites -Have complex life cycles => use vertebrate animals as primary host (where adults live), but also use one or more intermediate hosts -Intermediate hosts => dispersal agents for reaching new primary hosts - use of IHs requires specialized larval stages -ALL hosts have defense systems (e.g., vertebrate immune system), parasites have evolved mechanisms to overcome defenses, for multiple hosts => parasites highly specialized for a unique lifestyle
How do lungfish breathe? When during vertebrate evolution did lungs evolve (i.e., at the base of which clade, where on the vertebrate tree)?
see study guide image Both Gill & Lung Respiration
About how many times has a snake-like form evolved from a limbed ancestor within living Lepidosaurs? What features can you generally use to determine a true snake from a legless lizard?
twice, in snakes and legless lizards legless lizards often have eyelids and/or ear opening
The -ptera ending in insect orders refers to what?
wing
