Chordates Part 2

What did segmented backbones help do

Expanded range of motion

What did jaws create

New feeding opportunities

A more complex brain in vertebrae helped how

Could develop hunting strategies or plan escape routes

What adaptations enables vertebrates to thrive on land

Lungs and limbs

Where did lungs and limbs originate from in tetrapods

Fishes

What are the characteristics of tetrapods

4 limbed vertebrae

Separate digits (fingers and toes)

Defined joints in limbs

What are the groups of vertebrae

Amphibians

Amniotes

What is the closest relative to tetrapods

Tiktaalik

What tetrapod traits do tiktaalik have

Flat head, dorsal eyes

Mobile neck

Pectoral(shoulder bone), pelvic girdle (hip bone)

Fins with bones

What fishier traits do tiktaalik have

Fins with rays

Scales

When were tiktaalik formed

375 MYA

Tiktaalik have no what like tetrapods

Operculum

Where did tetrapod originate

Aquatic habitats

Ability to respire air

Lungs

Ability to move on land

Fins developed into limbs

Body able to support its own weight

Stronger limbs, limb girdles, and vertebral column

Sense organs that function in air not water

Modification of eyes, ears, olfactory organs

Ability to eat dry food

Salivary glands

Skin that resists desiccation and abrasion

Keratinization and thickening epidermis

Ability to reproduce on dry land

Internal fertilization, direct development, amniotic egg

What is amphibians Greek for

Double life

What do amphibians control

Algae and insect populations

What can the toxins in amphibian skin serve as

Possible painkilling drugs

Amphibians are useful indicators of what

Environmental quality

Examples of decline in amphibian populations

1. Destruction of wetlands and forests

2. Chytrid fungus infection

3. Invasive species

4. Road mortality

5. Porous skin (vulnerable to pollution)

6. Collection for pet trade

Who were the first tetrapods

Amphibians

What did land offer to amphibians?

Space, shelter, food, O2

What helps keep eyes moist in amphibians

Tear glands and eyelids

Even though on land amphibians still

Retain a strong link to water

What are the 3 orders of extant amphibians

1. Gymnophiona

2. Caudata

3. Anura

What are Gymnophiona

Caecilians

Caecilians lack what

Limbs

What are examples of caudata

Salamanders and newts

Who do caudata reproduce most closely to

Insects

How do Caudata reproduce

Males deposit sperm packet near female, she takes packet into body, lays fertilized eggs in water

What does Caudata mean

Having tail

Examples of Anura

Frogs and toads

What does Anura mean

Without tail

Who were the first vertebrates to thrive on land

Reptiles

What era did reptiles dominate

Mesozoic

When did reptiles evolve

310 to 320 MYA

What is an amniotic egg

Shelled egg with 3 membranes and a yolk sac

What does the chorion do

Gas exchange

What does the amnion do

Protect

What does the allantois do

Waste removal

What do amniotic aggs help do

Produce on land and internal fertilization with a male intermittent organ

What reduces water loss from skin in reptiles

Tough, keratin scales

What do retiles kidneys excrete

Only small amounts of water

Are reptiles ectotherms or endotherms

Ectotherms

What type of fertilization do reptiles go through

Internal fertilization

How do reptiles give birth

Lay hard shelled eggs (Amniotes), few give live birth

What are greater and more efficient in reptiles

Lung capacity and circulation

What are tuatara

Ancient lineage of lizard like reptiles. (Not lizards)

Tuatara are sister to

Squamates (lizards,snakes)

Tuatara have no

Male copulatory organ, or external ear

How many species of tuatara are there

2

Where do tuatara live

Restricted to a few small islets off of New Zealand

Synapamorphies of mammals

1. Mammary glands

2. Hair or fur

What did the loss of reptiles do for mammals

Paved way for rapid diversification of mammals

When did mammals start to grow

After mass extinction 65 MYA

What helped provide new types of habitats and food for mammals

Flowering plants

What are the 2 subclasses of mammals

1. Egg laying monotremes

2. Live bearing mammals

   1. Marsupials

   2. Placental mammals

How many species of egg laying monotremes are there

5

Examples of egg laying monotremes

Duchbilled platypus and echidna

Egg laying monotremes have similarly anatomy to

Reptiles

Egg laying monotremes order of reproduction

1. Produce amniotic egg

2. Young hatches and reaches milk secreting pores in skin

3. Few months later offspring leaves and hunts its own food

Examples of marsupials

Kangaroos, opossums, wombats, Tasmanian devils

What is the only marsupial native to North America

Opossums

When do marsupials give birth

4 to 5 weeks after conception

How many of marsupials are found in Australia

2/3

Where do marsupials go once they are born

Into a marsupium or pouch

What is the most diverse group of mammals

Placental mammals

What does the placenta do

Nourish and remove waste from developing offspring

Where does the young develop in placental mammals

Inside females uterus

What does the placenta connect

Maternal and fetal circulatory systems

What are the 2 largest groups of placental mammals

Rodents and bats

What percent of rodents make up placental mammals

40%

What percent of bats make up placental mammals

20%

Crocodylia closest relatives are

Birds

How many chambers do crocodylia have

4

What are crocodylias skin lined with

Osteoderms (bony plates)

Examples of crocodylia

Crocodiles, caimans, alligators, gharials

Examples of testudines

Turtles and tortoises

How many Species of testudines are sea turtles

7

All testudines are what

Oviparous (egg laying)

What is the largest turtle

Leatherback

The shell plates of testudines are

Fused to vertebrae and ribs

Snakes have NO

External eardrum

Moveable eyelids

Voice

How do snakes smell

With their tongue

How many functioning lungs do snakes have

1

Most snakes are

Non venomous

How many snakes are venomous in LA

7