AP Bio Evolution 2

Biological Species Concept

Biological Species Concept

Defines species as a population that can produce fertile and viable offspring in nature.

Pre-Zygotic Barriers

Reproductive barriers that occur before syngamy.

Temporal Isolation

Breeding cycles don’t match, leading to reproductive isolation.

Mechanical Isolation

Breeding is attempted but unsuccessful due to physical incompatibility.

Gametic Isolation

Fusion between gametes doesn’t occur, causing the termination of the non-organism.

Behavioral Isolation

Nonrandom mating due to differences in behavior.

Post-Zygotic Barriers

Reproductive barriers that occur after syngamy.

Reduced Hybrid Viability

No viable and fertile offspring are produced.

Reduced Hybrid Fertility

Offspring is produced but is sterile.

Hybrid Breakdown

First generation produces fertile and viable offspring, but subsequent generations are weak and unable to reproduce.

Allopatric Population

A population that is separated by a barrier and exposed to different environments.

Allopatric Speciation

Reproductive isolation occurs between the two populations due to differences in gene pools and extreme clines.

Sympatric Population

Two different species that coexist in the same environment.

Sympatric Speciation

One population splits into two based on behavioral isolation.

Cladograms

Graphs or charts that show inferred common ancestry and related characteristics.

Gradualism model

A model of evolution where change occurs slowly over time.

Punctuated Equilibrium Model

A model of evolution where there are sudden, rapid changes leading to the formation of two populations.

Evolutionary Development

Interdisciplinary science between evolutionary biology and the study of development.

Gene regulation

Control of gene expression in development.

Phylogeny and Systematics

The study of evolutionary relationships and classification of organisms.

Fossil Formations

The process of fossilization.

Radioactive Dating

Measuring the amount of half-lives that have passed to determine the age of a sample.

Geological Timescale

Divided into three eras - Precambrian, Paleozoic, and Cenozoic.

Allopolyploid

Organism with a different diploid number than both parents, resulting from two species.

Autopolyploid

Difference in chromosome number in offspring of the same species, resulting in a tetraploid.

Mass extinctions

Periods of time with a significant loss of biodiversity.

Iridium

Radioactive element found in a layer separating dinosaur and non-dinosaur fossils.

Phylogenetic Tree

Diagram showing inferred common ancestry and evolutionary relationships.

Law of Parsimony

The simplest explanation is typically correct.

Monophyletic

Explains common ancestry for one clade.

Shared primitive

Homology feature predating a taxon in all species.

Shared derived

Something new and unique to a clade or species.

Outgroup comparison

Comparison to an external group to determine evolutionary relationships.

Adaptive Radiation

Changes that occur when moving away from a common ancestor.

convergent evolution

the process by which two unrelated and dissimilar species come to have similar traits, often because they have been exposed to similar selective pressures.