vertebrates

What are the two main examples of Agnathans?

Hagfish and Lamprey.

How do hagfish and lampreys differ in habitat and feeding?

Hagfish are marine scavengers with slime glands; lampreys are freshwater/marine and often parasitic.

Why are lampreys harmful to the Great Lakes?

They are parasitic and damage native fish populations.

When did jaws first appear in vertebrates?

Around 440 million years ago.

From what structure are jaws thought to have evolved?

Modified gill arches.

How did the evolution of jaws change animal feeding and survival?

It allowed active predation and expansion into new ecological niches.

What material makes up the skeletons of cartilaginous fish?

Cartilage.

What does the Ampullae of Lorenzini detect?

Electrical signals such as prey heartbeats.

What does the lateral line system detect?

Vibrations and movement in the water.

What are the three reproductive modes in cartilaginous fish?

Oviparous (eggs), Ovoviviparous (eggs hatch inside), Viviparous (live birth).

What major conservation issue affects cartilaginous fish?

Shark finning — around 100 million sharks killed annually.

Why does their sensory system make them top predators?

They detect prey movement and electric signals even in murky water.

What are the two main groups of bony fish?

Ray-finned and Lobe-finned fish.

What key structures define ray-finned fish?

Bony rays in fins, operculum for breathing, and swim bladder for buoyancy.

What are lobe-finned fish important for evolutionarily?

They are ancestors to tetrapods and could use fins to “walk.”

How did lungs in lobe-finned fish help animals move to land?

Allowed oxygen intake in low-oxygen water and later on land.

Why are amphibians tied to water for reproduction?

Their eggs lack waterproof shells and dry out easily.

How do most amphibians breathe?

Buccal pumping or through their skin.

What disease is threatening many amphibians?

Chytrid fungus.

Why are amphibians environmental indicators?

Their permeable skin makes them sensitive to pollution and habitat change.

What is the evolutionary advantage of the amniotic egg?

It allows reproduction away from water.

What are the three skull types and examples?

Anapsid (turtles), Synapsid (mammals), Diapsid (lizards, birds).

Why was the amniotic egg crucial for land colonization?

It let embryos develop safely in dry environments.

What groups are included in reptiles?

Turtles, lizards, snakes, crocodiles, and birds.

What are main traits of reptiles?

Keratin scales, lungs, and mostly ectothermic.

Which reptiles have temperature-dependent sex determination (TSD)?

Turtles and crocodiles.

What percentage of reptiles are threatened?

About 20%.

Why are turtles and crocodiles at higher risk than other reptiles?

Habitat loss and slow reproduction.

Are birds endothermic or ectothermic?

Endothermic.

What adaptation allows efficient breathing in birds?

Nine air sacs for unidirectional airflow.

What are feathers derived from?

Modified scales.

How do lightweight bones and air sacs help birds fly?

Reduce weight and supply continuous oxygen.

What are defining traits of mammals?

Hair, mammary glands, endothermy, and differentiated teeth.

What glands produce oil and sweat?

Sebaceous and sudoriferous glands.

What are monotremes?

Egg-laying mammals (platypus, echidna) that secrete milk from the abdomen.

What are marsupials?

Mammals with brief gestation; young finish development in pouch (e.g., opossum).

What are eutherians?

Placental mammals with long gestation.

What is the difference between altricial and precocial young?

Altricial are helpless at birth; precocial are self-sufficient.

Why do marsupials have shorter gestation periods?

They complete development externally in the pouch.

What percent of cartilaginous fish and reptiles are endangered?

Around 20%.

Why do “charismatic” species get more conservation attention?

More public and financial support.

Why is it important to protect non-charismatic species?

Ecosystem balance depends on all species, not just famous ones.

What are the two suborders of whales?

Mysticeti (baleen) and Odontoceti (toothed).

What methods are used to study whales?

Visual and acoustic surveys, satellite tagging, eDNA, and strand dissection.

What does bioacoustics study?

Whale communication, feeding, migration, and ship noise effects.

How can acoustic data inform whale conservation?

Reveals migration routes and stress from human noise for protection planning.

How does endothermy benefit animals?

Maintains body temperature for activity in changing environments.

What two evolutionary steps allowed vertebrates to fully live on land?

Development of the amniotic egg and lungs/limbs from lobe-finned ancestors.

How are physiology and conservation connected?

Species traits like reproduction and metabolism affect vulnerability to threats.