Zoology Key Vocab

Mesopredator

a predator that is at a mid-ranking trophic level in a food web

Clade

 a group of organisms including its past evolutionary descendants from the common ancestor

Monophyly

 a group of organisms including its past evolutionary descendants from the common ancestor

Paraphyly

 A group that includes the last common ancestor and some but not all current descendants

Polyphyly

A taxonomic group that contains species that are grouped together but don't have a direct recent common ancestor

Taxonomic Group

 The hierarchical classification of biological organisms

Homology

Shared ancestor leads to similar traits with evolved functions

Convergence

Unrelated species develop similar traits due to similar environmental conditions

Reversion

The loss of ancestral traits through evolution

Phylogenetics

the study of evolutionary relationships among biological entities

Species

a group that can interbreed and produce fertile offspring

Hermaphrodite

 an organism that possesses both male and female reproductive organs/ produces both male and female gametes over the course of its life

Binomial Naming System

two part naming system using both the genus and the species

Tetrapod

 a group of vertebrate animals that have 4 limbs or leg like structures (includes those who lost their legs e.g. snakes and whales)

Extant

still in existence

Cryptic Diversity

two or more species that are near impossible to tell apart based only on morphology and so are often misclassified as a single species

Cambrian Explosion

a time of rapid diversification that marks the appearance of modern animal phyla (538.8 million years ago)

Blastopore

 the opening on the surface of an early embryo

Endoderm

the innermost layer of cells or tissues of an embryo

Ectoderm

 the outermost layer of cells or tissues of an embryo

Mesoderm

the middle layer of cells or tissues of an embryo

Blastocoel

the fluid filled cavity that forms in the blastula in an early stage of embryonic development

Archenteron

 digestive cavity of an embryo

Oviparous

lays eggs

Viviparous

gives birth to live young

Ovoviviparous

eggs hatch internally and give birth to live young

Detritus

dead and decaying organic matter

Spicules

spine-like structures found mostly in sponges to form their skeletal framework

Leucon-type canal system

the complex water current system found in sponges

Calcareous

Contains calcium

Intracellular

within a cell

Extracellular

Outside a cell

Radial symmetry

organisms with repeating parts arranged around a central axis

Bilateral symmetry

divisible into symmetrical halves

Diploblastic

having a body derived from only two embryonic cell layers (ecto+endoderm and no mesoderm)

Cnidocytes

 stinging cells found in Cnidaria that contain a harpoon-like organelle that delivers toxins

Nematocysts - Specialised cells found in jellyfish tentacles to sting prey

Nematocysts

 Specialised cells found in jellyfish tentacles to sting prey

Colloblasts

 specialised, multicellular structures that capture prey in comb jellies

Benthic

lowest ecological level of a body of water, includes the bottom sediment

HOX genes

genes that encode proteins to specify the identity of body parts along the anterior-posterior axis during embryonic development

Colonial organism

a group of genetically identical individuals create a functioning single unit

Zooid

an animal that is part of a colonial animal

Hydrostatic skeleton

skeleton in worms supported by hydrostatic fluid pressure or liquid

Calcareous skeleton

skeletons made out of calcium carbonate spicules

Cartilaginous skeleton

skeleton made out of cartilage

Epidermis

 the outer layer of the skin

Epicuticle

the waxy outer layer that covers plants, fungi and insects

Derived

traits evolved more recently, in descendants but not found in the shared ancestor

Primitive

 traits inherited from a distant common ancestor

Coelom

fluid filled body cavity that surrounds and contains digestive tract