Bio 1300 - Evolution

Evolution

there is among individuals of a species

variation

some variations are

heritable

there is between individuals within a species for

competition, resources

of the parents are passed on to the next generation

successful traits

traits that don’t aid reproduction and survival are

not passed on

due to evolution organisms become

adapted to their environment

genes that exist in 2 or more forms are called

alleles

alleles code for of the same protein

slightly different versions

a difference in alleles causes

variation in species

breeding plants and animals for desirable characteristics also known as selective breeding

artificial selection

the evolution of antibiotic resistance in bacteria is an example of

adaptation

what are the 5 types of evidence for evolution

fossil, anatomical, biogeographical, biochemical, embryological

you can see ancestors of modern species in fossil record, species appear at different times in fossil record, clear record of descent, increase in diversity over time

characteristics of fossil evidence

structures that were inherited from a common ancestor

homologous structures

examples of vestigial structures

stunted wings on an ostrich and remnants of pelvis in whales

the study of distribution of plants and animals

biogeography

Australia and South American have a large number of marsupials indicating where common ancestors once lived when continents were connected is an example of

biogeography

all forms of life have the same —————-

basic genetic system

these are examined to determine how closely related species are

DNA and proteins

two or more genes derived from common ancestors

homologous genes

these are homologous genes in different species, they indicate the species share a common ancestor

orthologs

gene transfer between species such as from a bacteria to a eukaryote

horizontal gene transfer

have similar stages of development and similar structures during these stages

embryos of vertebrates

development of a species refers to

ontogeny

evolutionary history of a species

phylogeny

a local group of individuals of the same species

population

populations are , they can change from gen to gen. As population changes the changes with it

dynamic, genetic composition

all of the alleles for every gene in a population

gene pool

most genes are , they exist as two or more alleles

polymorphic

the number of copies of a specific allele in a population divided by the total number of alleles for the specific genes in a population

the number of copies of a specific allele in a population divided by the total number of alleles for the specific genes in a population

genotype frequency

the number of individuals with a particular genotype in a population divided by the total number of individuals in a population

the relationship between allele and genotype frequencies in a population that is not evolving

Hardy-Weinberg equation

what are the Hardy-Weinberg conditions

no new mutations, no natural selection, no advantage for any one allele, large population, no migration, random mating

Hardy-Weinberg can be compared to actual allele and genotype frequencies so it can be determined

what causes the differences

changes in the gene pool from gen to gen

microevolution

microevolution involves the intro of that alter prevalance of genotypes

genetic variations and evolutionary mechanisms

genetic drift, migration, nonrandom mating

what are some examples beside natural selection that play a role in evolution

what plays a major role in evolution

chance

extreme phenotypes are favored

directional selection

favors intermediate phenotypes

stabilizing selection

favors two or more different phenotypes

diversifying selection

two or more alleles are kept in balance

balancing selection

a form of natural selection where certain individuals posses certain traits that make them more successful in reproduction

sexual selection

sexual dimorphism

the different appearance of 2 sexes resulting from different secondary sex characteristics refers to

one sex competing amongst themselves for mating opportunities

intrasexual selection

one sex choosing mates based on desirable characteristics

intersexual selection

changes in allele frequencies due to chance

genetic drift

type of genetic drift, a large population may be severely reduced in size by a disaster, the remaining individuals are unlikely to have the genetic diversity of the original large population refers to

the bottleneck effect

genetic drift in a new isolated colony

the founder effect

a form of genetic drift, changes in genes that do not effect reproductive success

neutral variation

the flow of genes between populations by migrating individuals

gene flow

mating between males with similar phenotypes increases proportions of homozygotes/mating between mates with dissimilar phenotypes increases proportions of heterozygotes

non-random mating

type of non-random mating, when inbreeding produces less fit homozygotes reducing a populations’ reproductive success

inbreeding depression

give rise to new alleles, most are deleterious (don’t help survival) but some are useful are favored by natural selection

mutations

cannot fashion perfect organisms

natural selection

historical constraints or existing structures

evolution is limited by

are often compromises

adaptations

adaptive

not all evolution is , chance effects the genetic structure of populations

selection can only existing variations

edit

gene duplication and exon shuffling

what are some new genetic variation examples