Evolution and Classifying Organisms Flashcards

Flashcards reviewing key vocabulary and concepts from a lecture on evolution and the classification of organisms.

Taxonomy

The science of classifying organisms.

Binomial nomenclature

A system of naming organisms in which each species is given two Latin names: genus and species.

Eubacteria

Kingdom of the most abundant organisms on Earth, unicellular and prokaryotic, often causing disease and acting as decomposers.

Archaebacteria

Kingdom of unicellular and prokaryotic organisms that live in extreme environments.

Eukarya

Domain containing organisms with eukaryotic cells that have a true nucleus and membrane-bound organelles.

Protista

An outdated kingdom of unicellular, multicellular, or colonial organisms that are heterotrophs or autotrophs, now known not to show any evolutionary relationships.

Fungi

Kingdom of mostly multicellular, heterotrophic decomposers.

Plantae

Kingdom of autotrophic, stationary organisms that perform photosynthesis.

Animalia

Kingdom of heterotrophic, multicellular organisms, most of which are able to move.

Overproduction

Populations outgrow their environments, causing some individuals to die.

Uniformitarianism

The earth's surface was the result of many small, gradual changes over a long period of time.

Fitness

How well an organism can survive and reproduce in its environment

Adaptations

Traits that make an organism well-suited (fit) for its environment.

Genetic variation

A measure of the genetic differences within a population.

Mutation

A new phenotype that is often an accumulation of many mutations but can be caused by just one.

Background extinction

The normal extinction rate of species.

Mass extinction

An event that causes many species to die around the world.

Gradualism

The theory that evolution occurs slowly but surely.

Punctuated equilibrium

The theory that species evolve rapidly followed by periods of little change (stasis).

Directional selection

One extreme phenotype becomes better suited for the environment, and the phenotypes shift in one direction.

Stabilizing selection

The intermediate phenotype shows the best fitness.

Disruptive selection

The intermediate phenotype is the least fit.

Genetic drift

A change in the population due to random chance.

Genetic bottleneck

When many individuals in a population are killed, the surviving individuals may have a very different allele frequency than the original population.

Founder effect

Genetic drift that occurs when a few individuals from an existing population colonize a new habitat.

Speciation

The formation of a new species when populations are isolated from each other.

Geographic isolation

Two populations become separated by a geographic barrier.

Behavioral isolation

Two populations have different mating behaviors, so the organisms have no desire to mate.

Mechanical isolation

The reproductive organs of two groups become so different they can no longer mate.

Temporal isolation

Two populations do not mate with the same timing (day v. night, different seasons, or even different years).

Prezygotic

Isolation mechanisms that occur before a hybrid zygote can be formed.

Postzygotic

Barriers that exist when chromosomes don’t match up, the hybrid offspring don’t form correctly or are sterile.

Phylogeny

The study of evolutionary history and the possible relationships between organisms; also known as cladistics.

Cladogram

A diagram that represents a hypothesis of how things have evolved.

Derived characters

Characters or features of an organism placed along the bottom of a cladogram.

Node

Where the branches come together on a cladogram.

Clade

A group comprised of an ancestor and ALL of its descendants.