Bio 203 Exam 3

clade/taxon

a group of organisms that share a common ancestor

Synapomorphy

shared derived character

Pleisiomorphy

any ancestral or primitive character

monophyletic

ALL descendants came from one common ancestor

polyphyletic

pertaining to a group of taxa derived from two or more different ancestors

paraphyletic

Pertaining to a group of taxa that consists of a common ancestor and some, but not all, of its descendants.

Eukaryote

A cell that contains a nucleus and membrane bound organelles

Unikonta

amoebozoans and opisthokonts

gastrula/gastrulation

two-layered cup form after elimination of blastcoel

Zygote

fertilized egg

Gamete

sex cell

Blastula

hollow ball of cells

Cleavage

A mineral's ability to split easily along flat surfaces.

Ectoderm

outermost germ layer; produces sense organs, nerves, and outer layer of skin

Endoderm

the inner germ layer that develops into the lining of the digestive and respiratory systems

Mesoderm

middle germ layer; develops into muscles, and much of the circulatory, reproductive, and excretory systems

ectoderm, mesoderm, endoderm

tissue layers

organ system

group of organs that work together to perform a specific function

blastopore

The opening of the archenteron in the gastrula that develops into the mouth in protostomes and the anus in deuterostomes

blastocoel

the fluid-filled cavity of a blastula

archenteron

The endoderm-lined cavity, formed during gastrulation, that develops into the digestive tract of an animal.

diploplastic

2 germ layers (ectoderm and endoderm)

Triploblastic

has three germ layers: the ectoderm, endoderm, and mesoderm.

radical symmetry

type of symmetry where animals have body parts arranged in a circle around a central point

bilateral symmetry

Body plan in which only a single, imaginary line can divide the body into two equal halves.

Asymmetrical Symmetry

Animals with no general body plan, these animals have no definite shape.

Segmentation

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

appendages

Structures such as legs and antennae that extend from the body wall.

filter feeders

organism that takes in water to filter out the food and then releases the extra water (clam, oysters, sponge)

Detritivore

organism that feeds on plant and animal remains and other dead matter

endoparasite

parasite living on the inside of its host

Ectoparasites

Parasites that feed on external surface of host.

Haploid

an organism or cell having only one complete set of chromosomes

Diploid

an organism or cell having two sets of chromosomes or twice the haploid number

Fitness

Ability of an organism to survive and reproduce in its environment

Choanocytes

Collar cells that line the body cavity and have flagella that circulate water in sponges

Amoebocytes

Cells that move using pseudopods and perform different functions in different animals

Porocytes

Tubular cells that allow water to flow from the outside of the sponge to its central cavity

Spicules

Found in sponges, these consist of inorganic materials and support the animal

Sponging

have two sponge-like structures that collect liquid food and move it into the food canal.

spongocel

The central cavity of a sponge.

Ostia/Ostium

The intake pores on a sponge

Gonads

ovaries and testes

Gemmules

As proposed by Darwin, the units of inheritance, supposedly accumulated in the gametes so they could be passed on to offspring.

Endosymbiotic

a smaller organism that lives within another organism, the theory of how eukaryotic cells were formed.

Nematocysts

Small capsules that contain a toxin which is injected into prey or predators

gastrovascular cavity

Digestive chamber with a single opening, in which cnidarians, flatworms, and echinoderms digest food

polyp and medusa

two body forms of cnidarians

Adaption

A trait that helps an organism survive and reproduce

constraint

limitation or restriction

Trade-off

the act of giving up one benefit in order to gain another, greater benefit

marine

related to the sea; existing in or produced by the sea

Terristrial

living on land

dispersal

the movement of organisms from one place to another

Sessile

Describes an organism that remains attached to a surface for its entire life and does not move

Planktonic

Describes bacteria that are freely floating in water.

Gametogenesis

production of gametes

external fertilization

The process by which the female lays eggs and the male fertilizes them once they are outside of the female

internal fertilization

Process in which eggs are fertilized inside the female's body

Fission/Mitosis

part of eukaryotic cell division during which the cell nucleus divides

Meiosis

Cell division that produces reproductive cells in sexually reproducing organisms

Budding

A form of asexual reproduction of yeast in which a new cell grows out of the body of a parent.

Fragmentation

A means of asexual reproduction whereby a single parent breaks into parts that regenerate into whole new individuals.

parthenogenesis

Asexual reproduction in which females produce offspring from unfertilized eggs.

apomictic

not involving the fusion of male and female gametes in reproduction

Oviparity

egg laying

Viviparity

live birth

Ovoviviparity

Fertilized eggs are kept within mother to complete development, young obtain food from egg yolk

spawning

method of reproduction in fishes and some other animals where a large number of eggs are fertilized outside of the body

copulation

sexual intercourse

courtship

The process of finding a mate

female choice

females actively select their desired mates

Interspecific

competition between members of different species

Intraspecific

competition between members of the same species

Hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

Pheromones

Chemical signals released by an animal that communicate information and affect the behavior of other animals of the same species.

Environmental cues

A change in the external environment that triggers a change in behavior or physiology

monoecious

having male and female reproductive organs in the same plant or animal

dioecious

Having male and female reproductive organs in separate plants or animals

simultaneous hermaphrodites

individuals that possess male and female reproductive functions at the same time

sequential hermaphrodites

individuals that possess male or female reproductive function and then switch to the other

selfing hermaphrodites

individuals that possess the ability to do self fertilization

colonial animals

Organisms that live attached to one another by a thin membrane and so have shared nutrition; e.g. the coral polyp

Zooid

an animal arising from another by budding or division, especially each of the individuals that make up a colonial organism and typically have different forms and functions.

Polymorphism

The coexistence of two or more distinct forms in the same population.

Mesoglea

in cnidarians, the jellylike material located between the ectoderm and the endoderm

spiral cleavage

Cells divide in a spiral arrangement

radial cleavage

Cells divide parallel or perpendicular to axis to each other

monozygotic twins

twins who are genetically identical

coelom

body cavity lined with mesoderm

schizocoely

the method of coelom formation in protostomes in which the embryonic mesoderm splits into two layers

enterocoely

The method of coelom formation in deuterostomes in which the embryionic mesoderm develops from pouches within the archenteron.

Ediacaran Period

geological period (630-542 million years ago) when the oldest definite multicellular organisms with tissues evolved

Protostome

an animal whose mouth is formed from the blastopore

trochophore larva

Distinctive larval stage observed in annelids and molluscs.

lophophore

a crown of ciliated tentacles that function in feeding

Acoelomate

an animal that lacks a coelom, or body cavity

aposematic coloration

Bright warning colors in animals with a chemical defense.

definitive host

the host in which the sexual reproduction of a parasite takes place

intermediate host

a host that gives food and shelter to immature stages of a parasite