Chapter 29: Vertebrate evolution and diversity

Tunicates

(subphylum Urochordata) -Tunicates quirt water when their siphons are disturbed -They live in the ocean and are filter-feeders -The larva is bilaterally symmetrical and has all four chordate characteristics -Adults are sessile, thick-walled, sac-like organisms -The only chordate characteristics remaining in the adults are pharynx and gill slits

Notchord

-Dorsal supporting rod located below nerve chord

Turtles and tortises

-ribs and thoracic vertebrae fused into a heavy shell -Lack teeth but have sharp beak

Carnivore

eats meats

Bird Anatomy

-A four chambered heart completely separates 02- rich and 02- poor blood -Birds are endothermic, like mammals and maintain a constant internal temperature due to metabolic heat: feathers also help maintain body temp -Birds have no bladder and excrete uric acid in a semi dry state

Vertebrate Chordates

-Amphibians were the first to have jointed appendages -Lobe-Finned fishes from the Devonian era had fleshy appendages with bones homologous to those of terrestrial vertebrates -Reptiles and mammals had terrestrial adaptations for reproduction

Pharyngeal Puches

-Aquatic vertebrates become gills -Seen only as embryos in most vertebrates -Terrestrial vertebrates modified for various purposes

Marsupials

-Begin development within female's body -Are born very immature -Complete development within a pouch near the mother's abdomen: attach to nipples of mammary glands within the pouch and continue to develop -Mainly found in Australia due to adaptive radiation: kangaroo and koalas _ Virginia Opossum: only marsupial species north of Mexico

Bird orders

-Birds that catch prey with notched beaks and sharp talons -Shorebirds with long, slender, probing beaks and long stilt - like legs -woodpeckers with sharp, chisel-like beaks and grasping feet -Waterfowl with broad beaks and webbed toes

Adaptions to land

-Body covered with scales to protect against desiccation and against predators -Well-developed sense organs---snakes have a tougue modifies as sense organ -well-developed lungs protected by a rib cage -Three chambered heart

How do reptiles regulate their body temperature

-Exposing to the sun when in need of warmth -Hiding in shadows if they need cooling off

Postanal Tail

-Extends beyond the anus -In humans, tail disappears in the embryo stage

Vertebrate Chordates

-Fishes, amphibians, reptiles, birds, mammals -Cartilaginous fish: first to develop jaws -Some early bony fish had lungs

Monotremes

-Have a CLOACA --- terminal region of digestive tract that serves as a common chamber for feces, excretory wastes and sex cells -LAY HARD SHELLED AMNIOTIC EGGS -Secrete milk onto body surface (both males and females): Babies lick up the milk -Exist only in Australia: Spiny ECHIDNAS and duck-billed platypus

Skull

-High degree of cephalization -Encloses and protects the brain -Complex sense organs

Milestones in vertebrate evolution

-Jaws allowed for predation -Limbs allowed for locomotion -Amnion and shelled egg allowed for reproduction on land

Internal organs

-Large coelom and complete digestive tract -Closed circulatory system -Respiratory system consisting of gills or lungs -Kidneys serve as excretory and water-regulating organs that regulate water balance in the body -Sexes are separate and reproduction is sexual

Snakes

-Likely lost limbs as an adaptation for burrowing -carnivorous -some are venomous

Adaptations of placental mammals on land (except marine mammals )

-Limbs that allows rapid movement -Lungs expanded by rib cage and diaphragm -Four-chambered heart -Constant internal body temperature -Body-insulating hair -Well-developed brain, enlarged due to expansion of cerebral hemispheres -Differentiated teeth: incisors and canines have cutting edges for capturing and killing prey at the front of the mouth _ Premolars and molars chew food on the sides of the mouth

Endoskeleton

-Living tissue that grows with the animal -Protection for internal organs -Attachment for muscle -Paired appendages characteristic

Crocodillians

-Long powerful jaws -Muscular tail used as a weapon and a paddle

Lizards

-Most have four clawed feet -Carnivorous, herbivorous, or omnivorous

Placental mammals are classified by methods of obtaining food and made of locomotion

-Order Chiroptera: bats; wings supported by digits for flight -Order Perissodactyla: horses; long, hoofed legs for speed -Order Cetacea:Whales; paddle-like forelimbs

Dorsal Tubular Nerve Chord

-Protected by vertebrae -Anterior portion becomes brain in most chordates

Vertebral Column

-Replaces the embryonic notochord -Evidence of segmentation

Bird flight anatomy

-The forelimbs are modified as wings -Hollow, very light bones contain air cavities -A beak has replaced jaws with teeth -Large sternum aids attachment of flight muscles -Lobular lungs form air sacs to increase the efficiency of gas exchange -Flight requires acute sense organs and a well developed nervous system: good vision and developed brain, excellent muscle reflexes, enlarged brain region for instinctive behavior -An enlarged potion of the brain is responsible for instinctive behavior: Ritualized courtship before mating, strong parental care of young unable to fly, seasonal migration over very long distances

Diversity of birds

-The majority of birds can fly -Some birds are flightless -Birds are traditionally classified based on beak and foot type

Adaptations for reproduction on land

-The male penis passes sperm directly into the female -Fertalization is internal; female possesses shelled -The amniotic egg made development on land possible and eliminated the need for swimming larval stage

Tuataras

-Third eye -Only member of ancient group that included common ancestor of modern lizards and snakes

Nonvertebrate chordates

-Tunicates and lancelets -Do not have a vertebrae!

4 characteristics of chrodates

1. Notchord 2. Dorsal Tubular Nerve chord 3. Pharyngeal Pouches 4. Postanal Tail

How do sharks and rays detect prey

1. They can sense electric currents in the water 2. The use of a series of pressure-sensitive cells along both sides of body called LATERAL LINE SYSTEM 3. They have a keen sense of small with an enlarged part of the brain associated with this sense

Characteristics of Vertebrates

1. Vertebral Column 2. Skull 3. Endoskeleton 4. Internal Organs

Omnivore

Eats both meat and vegetation

Herbivore

Eats vegetation

Caecilians

Fossorial wormlike amphibians that are limbless and spend most of time underground and they do not have joined appendages

Mammals are classifies as __________, __________, or __________

Monotremes, Marsupials, or Placentals

Chordates

Phylum Chordata

Lancelets

Subphylum Chephalichordata -Knife shaped bodies a few centimeters long -Live in shallow costal waters -Retain all four chordate characteristics as an adult -Segmentation is present -Muscles are segmentally arranged -Nerve cord has branches

Placental Mammals

The majority of mammals -Extraembryonic membranes of reptilian egg are modified for internal development -Development occurs within the uterus -Portions of the uterine will contribute the maternal part -Materials are exchanged between fetal and maternal blood

Amphibians

class Amphibia -class mane means living on land and water -includes salamanders, frogs, toads, newts -joined appendages -four limbs -eyelids to keep eyes moist -Ears (a tympanum) to puck up sound waves -Larynx for vocalization -Larger brain than in fish relative to body size -small lungs in adults: gas exchange also occurs across moist skin -three chambered heart: two atria and a ventricle -Amphibious lifestyle: Larval stages in water, adults on land---Reproduction generally occurs in water

Cartilaginous Fishes

class Chondricthyes -This class is made up of sharks, skates, and rays -Skeletons comprised of cartilage instead of bone -Sharks vary in size -dogfish sharks used in biology labs is relatively small -Whale sharks are largest -Skates aren rays are flat fishes and live partly buried in sand they feed on mussels, clams, and various crustaceans

Mammals

class Mammalia -Also evolved from reptiles -Chief characteristics are body hair and milk----producing mammary glands -Almost all are endothermic ----- hair provides insulation against heat loss -Very efficient respiratory and circulatory systems -High level of care for the young

Bony Fishes

class Osteichthyes -RAY FINNED FISHES most commonly eaten -paired fins supported by bony rays -swim bladder for buoyancy -streamlined shape -bony scales for protection -water pumped across gills: enters through the moth exists out of the gill slits -Blood pumped by a tow-chamber heart though single-circuit circulatory system -Lobe-finned fishes: evolved into the amphibians -had fleshy appendages could be adapted for locomotion on land -most had lungs

Reptiles

class Reptilia -Extinct reptiles include mammal-like reptiles and dinosaurs -Evidence suggests birds are living dinosaurs -Today's reptiles include turtles, crocodilians, snakes, lizards, tuataras and birds

Birds

class of Aves -Sizes range from the hummingbird at 1.8g to the ostrich at a weight of 160kg -The fossil record as well as molecular data provides evidence that birds evolved from reptiles -BIRDS ARE NOW CONSIDERED PERT OF REPTILIA -Feathers are modified scales; legs of birds have scales -Amniotic egg with a hard shell insted of lethergy eggs of reptiles

Living reptiles excluding birds are __________ meaning their body temperature is the same as that of the environment (including fish and amphibians)

ectothermic

Nearly every anatomical feature of a bird can be related to its ability to _____

fly

What are the three types of fish

jawless, cartilaginous, and bony

The first fishes were _______ fish then _______

jawless, lungs

Jawless fish

superclass agnatha -Cylindrical body shape with smooth, scaleless skin -no jaws or paired fins -hagfish are scavengers -lampreys are parasitic: mouth modified to form a sucker, attach to other fish, water moves in and out of gills directly and not though moth as in other fish