Evolution/ Invertebrate Vocabulary Part 1

Vertebrate

Chordates with a backbone

Invertebrate

Animals that lack a backbone

Sessile

An organism that lives attached to the bottom or to a surface

Suspension Feeder

An animal that feeds on particles suspended in the water

Filter Feeder

A suspension feeder that actively filters food particles

Deposit Feeder

An animal that feeds on organic matter that settles on the bottom

Spicule

Any of the small calcareous or siliceous bodies embedded among the cells of sponges or in the tissues of other invertebrates

Spongin

The resistant fibers of sponges

Radial Symmetry

The regular arrangement of similar body parts around a central axis

Nematocyst

The stinging structure of cnidanans

Polyp

The cylindrical, typically attached stage of cnidarians

Anterior

The defined front end of a bilaterally symmetric animal

Posterior

The defined rear end of a bilaterally symmetric animal

Dorsal

The upper or back surface of an animal with bilateral symmetry

Ventral

The underside or belly surface of an animal with bilateral symmetry

Hydrostatic Skeleton

A system that uses water pressure against the body wall to maintain body shape and aid in locomotion

Closed Circulatory System

A circulatory system where the blood or circulatory fluid is contained in district vessels

Inherited Variation

The presence of innate differences between life forms that are passed from parents to offspring

Natural Selection

A mechanism of evolutionary change that results when individuals that are better adapted then others in the meeting the challenges of the environment produce more offspring

Genetic Mutation

A change in gene’s DNA sequence to produce something different

Convergent Evolution

Evolution in which two different species evolve similar structures because of similar life styles

Divergent Evolution

The process by which interbreeding species diverged into two or more evolutionary groups

Coevolution

The process in which one species evolves in response to another

Adaptation

Modification of an organism or its parts that makes it more fit for existence under the conditions of its environment

Evolution

A change in the genetic makeup of a species, usually as a result of natural selection favoring some individual characteristics over others

Variation

Any difference between the individuals in a species or groups of organisms of any species

Overproduction

When species reproduce many more offspring than can possibly survive