The theory/law of Evolution

All life forms are derived from pre-existing forms and their differences are due to changes in the heritable characteristics of biological populations over successive generations. This is one of the core concepts of modern biological theory.

Transmutation

Species change over time -Increasing complexity -Inheritance of acquired characteristics

Principles of Evolution

-Populations exhibit phenotypic variation -More offspring are produced that can survive -This results in a struggle for existence -Favorable traits may be selected for naturally Advantages in survival allow some individuals to more successfully pass their genes to the next generation --Over time, populations will change, becoming more adapted to their environment, and new species will arise -

Hardy-Weinberg Theorem

-Why don't dominant alleles become fixed in a population(i.e. why do recessive traits persist?)?

Calculation for allele frequencies(Hardy-Weinberg)

Let p equal the frequency of the dominant allele Let q equal the frequency of the recessive allele p+q

Calculation for genotype frequencies(Hardy-Weinberg)

p^2=frequency of homozygous dominant genotypes q^2=frequency of homozygous recessive genotypes 2pq=frequency of heterozygous genotypes and p^2+2pq+q^2

Hardy-Weinberg Equilibrium

Allele frequency values remain constant over time, if certain conditions can be satisfied

Conditions for Hardy-Weinberg Equilibrium

1. No mutations 2. No gene flow- Population must be isolated from all other populations 3. Large population size 4. Random mating 5.No natural selection- Equal survivability for all genotypes

Evolution

Any change in allele frequency in a gene pool over time -Naturally occurring populations evolve over time -Hardy-Weinberg Equilibrium provides a standard for detecting evolutionary change

Microevolution

A microevolutionary process Altering the gene pool over generations -changes in allele frequencies Agents of change -mutations -gene flow -non-random mating -genetic drift -natural selection

Gene mutations

Part of Microevolution Mutating the DNA can alter allele frequencies

Gene flow

Part of Microevolution Will alter allele frequencies in gene pool

Non-random mating

Part of Microevolution Increases homozygosity(makes populations more similar) -assortative mating -in-breeding and self-breeding

Genetic drift

Small populations are susceptible to this -allele frequencies change due to chance events

Founder effect

Small founding population

Genetic bottleneck

Small surviving population

Natural selection

A Microevolutionary process Differences in survival and reproduction lead to a 'natural' selection for the most 'fit' phenotypes ONLY works on phenotypes

Fitness

A Microevolutionary process The relative contribution an individual makes to the next generation(i.e. reproductive success)

Adaptation

A Microevolutionary process The selection for phenotypes that are suited to the environment and that increase fitness

Selective forces

A Microevolutionary process -directional selection -stabilizing selection -disruptive selection(splits population in two) -dimorphism -polymorphism -sexual selection -sexual dimorphism -female choice -male competition -lekking behavior

Macroevolution

The effect of microevolutionary changes over long periods of time, resulting in lineages of organisms

Species

The basic unit of biological classification They may exhibit a great deal of variation

Species concepts

Morphological species concept Biological species concept -genetic(reproductive) isolation Ecological species concept -a species includes all individuals that have the same niche Phylogenic species concept -a species includes all individuals that share the same ancestor

The process of speciation

Allopatric speciation(geographic isolation) Sympatric speciation(no geographic isolation) -autoploidy(doubling of chromosomes, happens due to nondisjuction, same species breeding) -alloploidy(each chromosome now has a homolog with which to pair during meiosis, happens due to hybridization, different species breeding) Hybrid(recombinational) speciation

Autoploidy

Same species breeding Happens due to nondisjuction Doubling of chromosomes

Alloploidy

Different species breeding Happens due to hybridization Each chromosome now had a homolog with which to pair during meiosis