Bio Sci 2 Exam 2

Chordata

• - A dorsal, hollow nerve cord
• - A notochord
• - Pharyngeal slits
• - A muscular, post-anal tail

A flexible, supportive, longitudinal rod

The are small, blade-like chordates that live in marine sands

1.3 million

A monotreme, a small group of egg-laying mammals

Have a head

Have a backbone

Have jaws and two pairs of limbs

Terrestrially adapted eggs

Hagfishes and lampreys

• The notochord is the body's main support in the adults
• - Craniate
• - Lacks paired fins and hinged jaws

• –have a supportive notochord but also have rudimentary vertebral structures, making them vertebrates
• - Craniates
• - Lack a hinged jaw and paired fins

• - There are 40 species
• - Deep sea scavengers
• - They produce slime as an anti-predator defense
• - They are nearly blind but have excellent smell and touch

• - They are parasites that penetrate the sides of fishes with rasping tongues
• - Larvae resemble lancelets
• - They are suspension feeders that live in fresh water streams, where they feed buried in sediment

- They arose as modifications of skeletal supports of the anterior pharyngeal gill slits (originally used for trapping suspended food particles)

–The remaining gill slits remained as sites of gas exchange

• – Class Chondrichthyes, which includes sharks and rays
• – Ray-finned fishes that have lungs (or lung derivatives)
• – Lobe-finned fishes that have lungs (or lung derivatives) and muscular fins supported by stout bones.

• - Sharks and rays have a flexible skeleton made of cartilage
• - Most sharks are fast-swimming predators, with sharp vision and a keen sense of smell
• - Electrosensors on their heads and a lateral line system aid them in locating prey
• - Most rays are adapted for life on the bottom, with dorsoventrally flattened bodies and eyes on the top of their heads

Tuna and Trout

• - Internal skeleton reinforced with a hard matrix of calcium phosphate (CaPO3)
• - Flattened scales covered with mucus
• - Operculum to move water over the gills
• - A buoyant swim bladder (derived from an ancestral lung)

• 27,000
• - The greatest number of species of any vertebrate group

- Lobe-fins have muscular pelvic and pectoral fins, supported by rod-shaped bones

• - Coelacanths
• - Lungfishes
• - Tetrapods

Jawed vertebrates with limbs and feet

• - Includes frogs, salamanders, and caecilians
• - Most have tadpole larvae
• - They were the first tetrapods to be able to move on land (but some are still entirely aquatic)

• - Most live on land
• - They walk with a side-to-side bending of the body

- More developed for moving on land with powerful hind legs

• - Blind, limbless and they burrow in soil
• - Mainly live in tropical areas

• - In damp habitats
• - Moist skin supplements lungs for gas exchange
• - Many of them have poison glands for defense

Reptiles, birds, and mammals

A private pond in which the embryo develops

Snakes, lizards, turtles, crocodilians, and birds

Most diverse of the reptiles

• Closely related to lizards
• Limbless due to ancestors burrowing lifestyles

• Haven't changed much over time
• Uncertain of ancestral lineage

• Crocodiles and alligators
• They are the largest living reptiles

Pollinate flower, disperse seeds, and consume insects

• Bipedal (2-legged) vertebrates
• Have a backbone
• Feathers

• Flight
• Essential for temperature regulation

• Their feet grip tightly
• The tendons automatically flex when the bird squats on a branch
• The toes lock around the branches

• Richly provisioned external eggs
• No species bear live young

• Large and well-developed (6 - 11 times the size of comparable reptiles)
• Neural system is highly developed

~300 billion birds on Earth

• 30 Orders
• 193 Families
• 2099 genera
• About 9700 species

• Adaptive Radiation
• Evolutionary change and adaptation

The evolution of additional varied species adapted to different ecologies and behaviors

• Bill size and shape changes due to the type of food eaten
• Leg length changes in relation to perching and terrestrial locomotion
• Wing shape changes due to different patterns of flight
• Seasonal and social behavior (reproductive rate, life span, age of maturity, etc.)

• One egg at a time
• Very long life span

• Very short lifespan
• Large clutch sizes

More than 150 million years ago

• Late Cretaceous
• Beginning of the Pleistocene about 3 mya (about 25% of bird population lost)

• Similar leg structure
• Scales
• In both, females are the heterogametic sex
• Nucleated red blood cells
• Original link - Archaeopteryx

• Fine-grained limestone
• From late Jurassic (155-135 mya)

• There are now 7 specimens
• Crow-sized, bipedal ‘reptile’ with scales
• Blunt snout, many small teeth
• Feathers on wings and tail (probably entire body as well)
• Capable of gliding, weak flapping
• Feather veins were asymmetric (indication of flight)

• Endothermic amniotes
• Have hair, which insulates the body
• Have mammary glands, which produce milk

200 million years ago as nocturnal insectivores

• Marsupials
• Monotremes
• Euterians (placental mammals)

180 mya

• Duck-billed platypus
• Ecidna

• The embryos of marsupials and eutherians are nurtured by a placenta within the uterus
• The placenta allows nutrients from the mother’s blood to diffuse into the embryo’s blood

Virginia Oppossum

• They are commonly called placental mammals, because their placentas are more complex than those of marsupials
• Young complete development within mother