Second Semester Vocab Review

gene

Segment on the DNA strand that codes for certain traits in an organism

cephalization

Animals that have a brain or brain-like organ near the head of their body

placental

Mammal that carries it’s young inside the body until fully developed

homologous structure

Anatomical structures that share a common ancestry

DNA

The genetic material of most living things; found in the nucleus of living cells

posterior

The tail or rear end of an animal

species

A group of organisms that are closely related and can mate to produce

fertile offspring

antibiotic

Medicine used to treat a bacterial infection

recessive

A trait that is not common or seen very often in a group of organisms

autotroph

An organism that can make its own food by photosynthesis

bilateral symmetry

A condition in which two equal halves of a body mirror each other

genotype

The genetic makeup of an organism using letters; BB, Bb, or bb

mantle

A layer of tissue that covers the body of many invertebrates

cutaneous respiration

The ability of amphibians to breathe through their skin

hermaphrodite

An organism that has both sets of sex organs

virus

A nonliving, infectious particle that can invade and destroy a cell

protozoa

A single-celled protist that can be aquatic or parasitic; examples include

amoebas and paramecia

nucleotide

DNA subunit that consists of a sugar, a phosphate, and a nitrogenous base

acoelomate

An organism that does not have a body cavity or organs

metamorphosis

A rapid change in an organism from egg to adult

cloaca

An opening in vertebrates where waste and sex cells exit

endothermic

An organism that can produce its own body heat and regulate it body

temperature

exoskeleton

Hard outer protective covering of some invertebrates

(arthropods and crustaceans)

heterozygous

Describes an individual that has two different alleles for a trait

dorsal

The top or back side of an organism

monotreme

An organism that lays eggs

budding

Asexual reproduction in which a part of the parent organism pinches off

and forms a new organism

pathogen

A virus or bacteria that causes disease

evolution

Change over time

taxonomy

The scientific study of describing, naming, and classifying organisms

DNA fingerprinting

The pattern of bands that results when an individual's DNA sample is fragmented,

replicated, and separated

double helix

The unique, twisted structure of DNA

radial symmetry

A body plan in which the parts of an animal’s body are organized in a

circle around a central point

tympanic membrane

A flap of skin on the head of amphibians that is used for hearing

vaccine

A killed or weakened virus given to humans to prevent sickness caused

by harmful pathogens

euglena

Protist that photosynthesizes and has a long flagella

foot

An appendage that some invertebrates use to move

purines

A nitrogenous base that has a double-ring structure;

either adenine or guanine

heredity

The passing of genetic traits from parent to offspring

punctuated equilibrium

Evolution that is described by short periods of drastic change in species, which are separated

by long periods of little or no change

countercurrent flow

In fish, an arrangement where water flows away from the head and blood

flows toward the head

dominant

Traits that are seen often in a species

marsupial

A mammal that carries and nourishes its young in a pouch

complementary

A characteristic of nucleic acids in which the sequence of bases on one strand is paired to

the sequence of bases on the other

homozygous

Describes an individual that has identical alleles for a trait

segmentation

The division of the body of an organism into a series of similar parts

paramecium

Heterotrophic protist that uses cilia to move

phenotype

The physical appearance of an organism

gradualism

Evolution in which slow change over a long period of time leads to biological diversity

terrestrial

An organism that lives most of its life on land

replication

The duplication of a DNA molecule

endoskeleton

Hard internal support structure of many organisms

pyrimidines

A nitrogenous base that has a single-ring structure; thymine or cytosine

fossil

The remains of an organism that lived long ago

lateral line

A faint line that runs the length of the fish’s body and marks the location of sense organs

that detect vibrations in water

algae

Eukaryotic organisms that convert the sun’s energy into food through

photosynthesis

adaptation

A change that improves an organism’s ability to survive

mammary gland

A mammalian structure located in the chest of a female that secretes milk

pseudopodia

Cytoplasmic extensions that function in food ingestion and movement in

certain amoebas

binomial nomenclature

The universal two word naming system used to identify living things

anterior

Front or head portion of an organism

heterotroph

Organism that eats other food for energy

prokaryote

A simple, single-celled organism that does not have a nucleus

cilia

Tiny hair extensions found on the surface of some protists; used for

locomotion

natural selection

The process by which individuals that are better adapted to their environment survive

and reproduce more successfully than less well adapted individuals do

operculum

A flap found on either side of a fish’s head that covers and protects the gills

jet propulsion

The ability of squid and octopus to move in the water by forcing water

out of their siphon

eukaryote

A complex organism that has cells with nuclei and various organelles

pseudocoelomate

An organism that has a false body cavity

ventral

The bottom or belly side of an organism

ectothermic

A cold-blooded animal that is dependent on the environment for heat; cannot regulate it’s

own body temperature

amoeba

Type of protist that uses jelly-like extensions of its cytoplasm to move

and eat food

gestation period

In mammals, the length of time between fertilization and birth

molting

Some organisms shed their outer exoskeleton for growth and development

flagella

Long whip-like tail used by some protists for locomotion

asymmetry

An organism that is irregular in shape; without symmetry

swim bladder

In bony fishes, a gas-filled sac that is used to control buoyancy

abdomen

The last or most posterior segment on an animal

sessile

Organisms that are permanently attached to the ocean floor

setae

Tiny hairs or bristles found on the underside of a segmented worm; used for traction and

movement

coelomate

An organism with a true body cavity containing many organs

cephalothorax

Organisms that have a fused 1st and 2nd body region

gills

Respiratory structures of fish that remove oxygen from the water