Chordates Part 1

Synapomorphies of chordata

1. Notochord

2. Dorsal, hallow nerve cord

3. Pharyngeal slits

4. Postanal tail

What is a notochord

Flexible rod, extends along chordates back

What replaces the notochord in adulthood by most chordates

Backbone that surrounds the spinal cord

What is the dorsal, hollow nerve cord

A cord that runs parallel to notochord

What makes up the nervous system in chordates

Spinal cord and brain

The nerve cord develops into what

Spinal cord

What is another word for pharyngeal slits

Gills or pouches

Where do slits or pouches form

In pharynx

In vertebrates pouches can develop into what

Gills

In humans pouches develop into

Middle ear cavity

What do invertebrates use pouches for

Feeding; strain food particles out of water

What common ancestor do chordata most likely have

Aquatic invertebrate

Vertebrates are only found in

The phylum chordata

What is the cranium

Bony or cartilage rich case that surrounds and protects the brain

What species is the earliest to have a cranium

Hagfishes

What is a vertebral column

Backbone; a protective flexible segmented backbone

What does the vertebral column protect

Spinal cord

What pro does a vertebral column give animals

Greater range of movement

What is the vertebral column made up of

A series of small bones or cartilage structures

Vertebral column provide attachment points for what

Muscles

What are jaws

Pair of bones that frame the entrance of mouth

Why was the development of hinged jaws so important?

Enhance ability to grasp prey or gather food items

Where did hinged jaws develop from

Modified gill support bones

What do fishes gills absorb and release

O2, CO2

What type of lungs do air breathing vertebrates have

Internal saclike lungs

Where do lungs derive from

Swim bladders of bony fishes

What do swim bladders do

Help control buoyancy in fishes

What are tetrapods

Vertebrate with two pairs of limbs

What do limbs enable

Animals to walk on land

What are examples of tetrapods

Amphibians, reptiles, birds, mammals

Some tetrapods have less than how many limbs?

4

What examples of tetrapods who have no limbs

Snakes and caecilians

What tetrapods limbs modified into flippers

Whales, dolphins, and sea lions

What is an amniotic egg?

Shelled egg with several membranes

What are amniotic eggs made of

1. Amnion

2. Chorion

3. Allantois

4. Yolk

What is the amnion

Fluid filed sac that cushions embryo from shock

What is the chorion

Helps with gas exchange between embryo and air outside of egg

What is allantois

Collects and stores wastes for embryo

What is the yolk

Contain nutrients for embryo

What are shelled eggs

Leathery or hard outer layer that allowed animals to reproduce entirely on land

Shelled eggs keep embryos from what?

Drying out

What are examples of amniotes

Birds, reptiles, mammals

What are Amniotes similar to in mammals

Protective structures that surround fetus in uterus

What are ectotherms

Body temperature fluctuate with environment

What do ectotherms lack

Internal mechanisms to keep their body temperature within narrow range

What is an example of behavior to help adjust temperature

Basking in the sun or burrowing in the ground

What are examples of ectotherms

Invertebrates, fishes, most amphibians, most reptiles

What are endotherms

Have to maintain constant body temperature using heat generated from own metabolism

How do endotherms maintain body temperature

By using enormous amounts of energy

The amount of energy used to maintain body temp causes what

Mammals to eat much more food than ectoderm’s the same size

What are examples of endotherms

Bird and mammals

How many heart chambers do fishes have?

2

How many heart chambers do amphibians and and most reptiles have

3

How many heart chambers do crocodilians, birds, and mammals have

4

What does more heart chambers mean?

Greater efficiency for blood to deliver O2 to tissues

What are invertebrate chordates called

Prochordates

What are examples of prochordates

1. Sea squirts/Tunicates

2. Lancelets

What are tunicates known as

Sea squirts

Adult tunicates retain only what

Pharyngeal slits

Tunicates mostly live where

Shallow ocean waters

What type of feeders are tunicates

Sessile filter feeders

What does tunic mean?

Protective flexible body covering

What do tunicates free swimming larval represent

Tadpoles

How does gas exchange occur in lancelets

Directly across the skin

Synapomorphies of hagfishes and lampreys

Have cranium

Lack jaws

Long slender bodies with gills

Sense organs clustered near head end

Who are the earliest group to have a cranium

Hagfishes

What are hagfishes

Invertebrate

What is an example of how hagfishes eat

Use raspy tongues to scavenge soft tissues of dead animals

What are unusual abilities that hagfishes have

Can slide flexible bodies in and out of knots to pull on food, escape predation, or clean themselves

What are hagfishes tentacles sensitive to

Touch and chemicals

Where are hagfish tentacles located

Near mouth to locate food

Who are the first vertebrates

Lampreys

Who are the simplest vertebrae

Lampreys

What are lampreys responsible for

The decline of lake trout and whitefish

Lampreys spend most of their life as

Larvae

Some species of lampreys are

Parasitic and use suckers to consume blood of fish

Vertebrae Characteristics

Vertebrae

Spinal cord

Pharyngeal gill slits

Post anal tail

Who are the most diverse and abundant vertebrates

Fishes

What are the 2 main clades(groups) of fishes

1. Cartilaginous fishes

2. Bony fishes

What are the subgroups of bony fishes

1. Ray finned fishes

2. Lobe finned fishes

Where is the lateral line located on fishes?

On the side of fishes

What does the later line on fishes do

Sense organ, detects vibration nearby and helps animal find prey, escape predation

What are cartilaginous fishes skeleton made of

Cartilage

What is the most ancient clade of fishes

Cartilaginous

Examples of cartilaginous fishes

Sharks, skates, rays

Cartilaginous fishes have no

Swim bladder, or gill covers

How many gill slits do cartilaginous have

5-7 gill slits

What are cartilaginous fishes skin covered by

Placoid scales

What is the largest fish known

Whale shark

What is the largest predatory species

Great white shark

What allows sharks to pursue prey rapidly

Flexible fins, lightweight skeletons, streamlined bodies, absence of armored body

What percent of fish species are bony

96%

What are the skeleton of bony fish made of

Bone

What is the gill cover called

Operculum

What are examples of ray finned fishes

Eels, minnows, catfish, trout, tuna, salmon

How many species of ray finned fishes are there

29,000

What fishes are most closely related to tetrapods

Lobe finned fishes

How many species of lobe finned fishes are there

10

What are lungfishes lungs closely related to

Lungs in tetrapods

Examples of lobe finned fishes

Lungfishes, coelacanths