BIO 103: Ch. 22 & 24 Origin of Species Vocab

Evolution

Any change in the inherited traits of a population that occurs from one generation to the next; i.e., over a time period longer than the lifetime of an individual in the population; (b) more simply defined, biological evolution is descent with modification

Fossil

A preserved remnant or impression of an organism that lived in the past.

Adaptation

Inherited characteristic of an organism that enhances its survival and reproduction in a specific environment.

Evolutionary Tree

A branching diagram that reflects a hypothesis about evolutionary relationships among groups of organisms.

Homology

Similarity in characteristics resulting from a shared ancestry.... anatomical homology (ex: bones in the forearms of a cat, whale, bat, and human), embryological homology (ex: hindlimb of a dolphin fetus), molecular homology (the shared molecular sequences -- ATCGs -- between organisms).

Convergent Evolution

Process by which unrelated organisms independently evolve similarities when adapting to similar environments; otherwise states, the evolution of similar features in independent evolutionary lineages

Biogeography

The scientific study of the past and present geographic distributions of species.

Microevolution

Evolutionary change below the "species" level (think biological species concept); simply the change in the allele frequencies (gene pool) in a population from generation to generation.

Macroevolution

Evolutionary change above the "species" level (think biological species concept); examples of macroevolutionary change include the origin of a new group of organisms thru a series of speciation events and/or the loss of organisms via extinction (sometimes at very high levels... mass extinctions)

Speciation

An evolutionary process in which one species splits into two or more species.

Species

[According to the biological species concept...] A population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups.

Biological Species Concept

Definition of a species as a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but are NOT able to produce viable, fertile offspring with members of other populations. This species concept (other species concepts out there including morphological, phylogenetic, ecological, etc) emphasizes the "biology" and the role of reproductive barriers (and subsequent reproductive isolation) in generating patterns of divergence.

Reproductive Isolation

The existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring. Types include prezygotic (pre-mating and post-mating) as well as postzygotic barriers to reproduction.

Prezygotic Barrier

A reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted

Postzygotic Barrier

A reproductive barrier that prevents hybrid zygotes produced by two different species from developing into viable, fertile adults.