Zoo3001 Chordates + Agnathostomes

Vertebrates are in the subphylum

deuterostomia

Vertebrates body plan

bilateral deuterostomes

Vertebrates germ layers

triploblastic eucoelomates

Vertebrates digestive system

complete

Vertebrates excretory system

kidneys to remove waste

Vertebrates circulatory system

closed system with heart

Vertebrates nervous system

brain with central nervous system

Vertebrates respiratory system

varies depending on group

- gills, lungs, skin

Most species fall into the subphylum

vertebrata aka craniata

Two groups which are an exception to falling under subphylum vertebrata are

Cephalocordata (lancelets) and urochordata (tunicates)

The five defining characteristics of all vertebrates

1. notocord 2. hollow dorsal nerve cord 3. pharyngeal slits 4. post-anal tail 5. endostyle/thyroid gland

In some species, the characteristics are only present during

embryonic dev

The notocord is

flexible but stiff rod structure derived from mesoderm tissue

The notochord runs from

anterior to posterior of body

The notochord is located

dorsal of the digestive tube and ventral of the nerve cord

The notochord provides

rigid support and muscle attachment sites

The notochord is known to be an

energy saver

In true vertebrates, the notochord has been replaced with the

vertebral column (spine)

The Hollow dorsal nerve cord is derived from

ectoderm

The Hollow dorsal nerve cord runs from

anterior to posterior of the body

Hollow dorsal nerve cord is located

dorsal of the notochord

Hollow dorsal nerve cord develops into

brain and spinal cord (central nervous system)

The Hollow dorsal nerve cord musnt be confused with the

vertebral column/backbone

Pharyngeal (gills) slits originated in

filter feeders, allowing water to enter mouth

In aquatic vertebrate fishes, water enters

mouth when feeding and exits through gill slits

In land vertebrates, the pharyngeal slits develop into

parts of the ear, tonsils, and thymus

The post-anal tail is the

posterior tail that extends beyond the anus

Post-anal tail main purpose is

locomotion

In aquatic species, the post-anal tail is the

tail/caudal fin

In terrestrial species, the post-anal tail has been

adapted for balance

In great apes and humans, the post-anal tail is reduced to the

coccyx

The Endostyle/thyroid gland is a

mucus producing tissue on the floor of the pharync

The Endostyle/thyroid gland produces

substance similar to thyroid hormones

The Endostyle/thyroid gland is important in

iodine metabolism

In most vertebrates, the endostyle is present at the beginning of ________ _________, but as development continues it develops into the ________ ________.

embryologic development; thyroid gland

Urochordata and cephalocordata have what as adults?

endostyle

The two chordate clades that are invertebrates are

extremely primative chordates (lancelets and tunicates)

Lancelets are

cephalochordates

Tunicates (sea squirts) are

urochordates

Lancelet adults have

all five characteristics

The tunicate larvae have all

five defining characteristics but adults only have pharyngeal slits and endostyle

Vertebrata/Craniata is the

largest group of chordata

The cranium is a

bony/cartilaginous/ligamentous structure surrounding the brain

Cranium includes

jaw and facial structures

Chordates have _ defining characteristics of vertebrata

5

One major novel evolutionary adaption in vertebrata

vertebral column (spine)

The vertebral column aka

- spine

- irregularly shaped bones joined together to form backbone

In vertebrata, embryos have a

notochord which develops into vertebral segments of a true backbone

The segments in embryos can be

cartilaginous or osseous

Two orders in vertebrata

agnathostomes and gnathostomes

Agnathostomes are

animals without jaw

Gnathostomes are

animals with a jaw

Two classes in agnathostomes

myxini and petromyzontidae

Gnathostomes are divided into

1. fish 2. tetrapods 3. four limbs 4. amphibians 5. amniotes 6. animals with egg containing extraembryonic membranes 7. animals adapted to terrestrial life (mammals, birds, reptiles)

Agnathostomes myxini are

hagfish

Agnathostomes petromyzontidae are

lampreys

Hagfish are

- blind scavengers

- have sensory barbels

- notochord for support

Hagfish have

keratin teeth on cartilage base

The keratin teeth help the hagfish to

rasp pieces of food from dead animals

Do hagfish have a vertebrae for body support?

No, a notochord instead

Lampreys are

- parasitic

- eyes + cerebellum

- simple vertebrae

Lampreys have a

suction mouth with rasping tongue

Lampreys are referred to as

ectoparasites

Both lampreys and hagfish have a

cartilaginous cranium