BIO 172 Ch. 34: Deuterostomes

What are the three major groups of chordates?

tunicates, lancelets, vertebrates

What animals are vertebrates?

fish, amphibians, reptiles, birds, mammals

As compared to vertebrates, lancelets and tunicates are ________.

nonvertebrate

What are the four major features of chordates?

dorsal nerve cord, notochord, pharyngeal slits, postanal tail

Dorsal Nerve Cord

nerve cord found in all chordates that forms the spinal cord and brain

Notochord

a flexible rod that supports a chordate's back

In vertebrates, the ________ is replaced by the vertebral column.

notochord

Pharyngeal Slits

a gill structure in the pharynx, found in chordate embryos and some adult chordates

Postanal Tail

muscular structure at the end of a developing chordate

Lancelets

fish-like filter feeders of near-shore marine environments

Tunicates

sponge-like sessile marine filter feeders

Tunicates are _________ at maturity and ________ in their larval stage.

sessile; free-swimming

What main characteristics distinguish vertebrates from nonvertebrate chordates?

vertebral column and neural crest

Vertebral Column

a series of bones called vertebrae that enclose and protect the spinal cord/dorsal nerve cord

Neural Crest

group of cells that develops from the embryo's ectoderm and contributes to the development of many vertebrate structures

What are the other distinguishing features of vertebrates?

distinct head, internal organs, endoskeleton

Distinct Head

houses sensory organs

Internal Organs

liver, kidneys, endocrine glands, heart, and closed circulatory system

Endoskeleton

internal skeleton or supporting framework made of cartilage or bone

The first vertebrates appeared in oceans about ________ million years ago.

530

In what order did vertebrates evolve in?

jawed fishes, tetrapods, amniotes, birds and mammals

Jawed Fishes

first vertebrates to become dominant

Tetrapods

vertebrate animals having four feet, legs or leglike appendages; included early amphibians

What animals first evolved onto land?

tetrapods

Amphibians

vertebrates that live in water and on land, smooth skin covers body, lay eggs, cold blooded

Amniotes

member of a clade of tetrapods that have an amniotic egg containing specialized membranes that protect the embryo; mammals, birds and reptiles

After the mass extinction of the Cretaceous period 66 million years ago, ________ and ________ become the dominant vertebrates.

mammals and birds