Animal Evolution Flashcards

Flashcards about the major phyla of the animal kingdom and animal evolution

Porifera

Sponges

Cnidaria

jellyfish, corals

Platyhelminthes

flatworms, tapeworms, flukes

Nematoda

roundworms

Mollusca

snails, clams, squids

Invertebrates

Animals that lack a vertebral column, or backbone

Vertebrates

Animals that have a backbone

Notochord

A rigid rod that runs the length of the body. It supports the body and gives it shape.

Incomplete digestive system

A digestive cavity with one opening. The single opening serves as both mouth and anus.

Complete digestive system

A digestive tract with two openings. One opening is the mouth. The other is the anus.

Fission

Takes place when an animal simply divides into two parts

Budding

May take place when a parent forms a small bump or bud. The bud remains attached to the parent while it develops into a new individual.

Ectoderm

Outer cell layer

Endoderm

Inner cell layer

Cephalization

The concentration of nerve tissue at one end of the body, forming a head region.

Bilateral symmetry

Animal can be divided down the middle to form identical right and left halves

Pseudocoelom

A partial body cavity that is filled with fluid.

Coelom

A fluid-filled body cavity, completely enclosed by mesoderm. It lies between the digestive cavity and body wall

Segmentation

Increases flexibility and permits a wider range of motion.

Sessile

Unable to move from place to place

Endoskeleton

An internal skeleton

Filter feeders

Collar cells have tiny hairs that trap the particles/food. Cells called amebocytes also help digest the food, in sponges.

Nematocyst

A long, thin, coiled stinger. It has a barb that may inject poison. These tiny poison darts are propelled out of special cells. They are used to attack prey or defend against predators, in cnidarians

Polyp

Has a tubular body and is usually sessile.

Medusa

Has a bell-shaped body and is typically motile

Cuticle

A tough covering on the surface of roundworms that prevents their body from expanding. This allows the buildup of fluid pressure in the pseudocoelom, creating a hydrostatic skeleton

Deposit feeders

Burrow through the ground, eating soil and extracting organic matter from it.

Mantle

A layer of tissue that lies between the shell and the body. It secretes calcium carbonate to form the shell

Radula

A feeding organ with teeth made of chitin.

Molting

Must be shed and replaced with a new one periodically throughout life.

Book lung

Stacked folds of tissue with air pockets in between the folds. Gases are exchanged between blood and air across the tissues

Trachea

Refers to a system of tubules that take in air through openings called spiracles. The tubules carry oxygen directly to tissues throughout the body

Pupa stage

The pupa is immobile and may be encased in a cocoon. Tissues and appendages of the larva break down and reorganize into the adult form.

Spines(Echinoderms)

They are part of the endoskeleton, not on the skin

Water vascular system

unique feature of echinoderms

Post-anal tail

The tail is opposite the head and extends past the anus. What is it.

Dorsal hollow nerve cord

The nerve cord runs along the top, or dorsal, side of the animal.

Notochord

Lies between the dorsal nerve cord and the digestive tract. It provides stiffness to counterbalance the pull of muscles.

Pharyngeal slits

Located in the pharynx, joins the mouth to the digestive and respiratory tracts.

Vertebral column

The main distinguishing feature of vertebrates

Cartilage

A tough tissue that contains a protein called collagen.

Bone

A hard tissue that consists of a collagen matrix, or framework, filled in with minerals such as calcium.

Ovipary

Development of an embryo within an egg outside the mother’s body

Ovovivipary

Development of an embryo inside an egg within the mother’s body until it hatches. The mother provides no nourishment to the developing embryo inside the egg.

Vivipary

Development and nourishment of an embryo within the mother’s body. Birth may be followed by a period of parental care of the offspring

Ectothermy

Regulating body temperature from the outside through behavioral changes

Endothermy

Regulating body temperature from the inside through metabolic or other physical changes

Spawning

Come together in a group and release gametes into the water at the same time

Tetrapods

Amphibians, vertebrates that exist in two worlds that divide their time between freshwater and terrestrial habitats.

Cloaca

A body cavity shared by digestive, excretory, and reproductive systems

Amniotic eggs

Reptiles, tetrapod vertebrates that produce amniotic eggs and have scales of very tough keratin that protect reptiles from injury, and also prevent them from losing water