AP Bio Unit 7 Vocab

LaMarck’s Theory

Evolution occurred through use and disuse. Species inherited acquired traits. Inaccurate

Darwin’s Theory

Species evolve over generations through random mutations that provide more fitness/advantage. Accurate

Natural Selection

The process by which individuals that have certain heritable traits survive and reproduce at a higher rate than other individuals because of those traits.

Fitness

Ability to reproduce and contribute genes to the next generation.

Alleles

Different versions of the genes for a trait located on a specific location in the chromosome. (either dominant or recessive alleles). Code for different phenotypes/physical traits.

Phenotypes

Observable traits of an organism.

Artificial Selection

When reproductive success is determined by human requirements (man-made)

Transitional fossils

Show evolutionary progression between groups

Isolation

When species are geographically separated, they evolve separately based on different selective pressures of the environment.

Vestigial Structures

Structures that have lost their primary adaptive purpose (hind legs of whales)

Homologous structures

Structures that were descended from a common ancestor, but evolved to have different functions.

Analogous structures

Structures that evolved multiple times in different lineages to fulfill adaptive needs, but were not descended from a common ancestor.

Phylogeny

Evolutionary relatedness of all organisms on Earth

Computational analysis

The ability to analyze large amounts of chemical sequence data to establish evolutionary relationships among organisms. 

Hardy-Weinberg Theory

The ability to quantify the amount of evolutionary change from generation to generation.

Population

Localized group of interbreeding individuals

Gene pool

Collection of alleles in the population

Allele frequency

How common the specific allele is in the population (dominant vs recessive alleles)

Evolution

Change in allele frequencies in a population over time (generations)

Non-Random Events

Natural, artificial, or sexual selection. Choosing certain traits out of preference.

Random Events

Mutations, genetic drift, migration/gene flow are random events, that can be caused by bottlenecks or the founder effect.

Genetic Drift

Random, non-selective changes in allele frequency due to chance. Can lead to loss of genetic diversity. Has a larger effect on smaller populations, since each individual is more of the total alleles.

Founder Effect

The descendants of a small, founding population have different allele percentages than the population the founders came from.

Bottleneck

Survivors of a catastrophic event may have drastically different alleles; their descendents will develop a different allele frequency.

Immigration

Alleles of the population that left are taken from the original population.

Emmigration

Alleles of the joining population are added to the population’s gene pool.

Sexual selection

Persistence of traits that signify fitness and aid in reproduction (what the females like, not necessarily evolutionary fitness)

Intersexual selection

Females are choosy among males with feather displays (non-random)

Intrasexual selection

Dominance competitions between males, fighting to the death or until one retreats. The one alpha male mates with all the females.

Directional Selection

Shifts the overall makeup of the population by favoring variants that are at one extreme of the variation. (Darker mice favored in fall, lighter mice favored in winter)

Disruptive Selection

Favors variants at both ends of the distribution, both of the extremes (patchy habit with light and dark rocks, intermediate colored mice disadvantaged)

Stabilizing Selection

Favors average/intermediate distribution, rather than the extremes. Both extremes are disadvantaged.

Biological Species

Organisms that can reproduce to create fertile, viable offspring.

Gradualism

Species slowly gradually evolve, are the product of small accumulating changes.

Punctuated equilibrium

Species undergo long periods of little change, then experience rapid, large evolutionary changes.

Adaptive radiation

One species evolve into many species after an extinction, many open niches available to occupy.

Allopatric Isolation

Happens due to physical separation, changes in habitat limiting the population available to mate. Two separate populations, over time, the same species evolves into different species.

Sympatric Isolation

Internal factors cause the same population to speciate into two different populations. One part of the population chooses to live in a different habitat of the same area (living in trees, no tree floor) or a new food source, or polyploidy plants

Polyploidy plants

Plants with an extra whole set of chromosomes, 4n chromosome number instead of 2n, can’t reproduce with diploid plant members to make fertile offspring.

Convergent Evolution

Separate species evolve the same phenotype due to a similar environment, but the adaptation is due to different genes.

Carbon-14

Produced after the living organism dies, it experiences radioactive decay over time. Less carbon-14 = older.

Divergent Evolution

One ancestral species living in the same environment with many niches, eventually due to adaptive radiation the one species will speciate into many different species due to selective pressures.