AP BIO EXAM Unit 6

Strata

Assembly of fossils varieties changed suddenly between different layers of sediment

Inheritance of acquired characteristics

Environment can produce physical changes in organism during lifetime that’s inheritable

Natural selection ideas

competition for limited resources, evolutionary fitness, environment changing/individual moves, mutation, population evolves

competition for limited resources results

in differential survival

evolutionary fitness

Individuals with favorable traits more likely to survive/reproduce desirable traits

Adaptation

any evolved trait helps an organism be more suited to environment

Physical mimicry

mimicry, camoflauge

mimicry

mimic something dangerous

Physiological adaptation

Resistance to pesticides/antibiotics, ability to adjust to climate change

Behavioral adaptation

Traits learned, some brain with trait

Evidence of evolution

fossils, biochemical evidence, anatomical, embryos

Transitional fossils

Bear resemblance to 2 groups thats classified different in present

Biochemical evidence

more related species means more similar DNA sequences

Homologous structure

Similar structures, different function

Analogous structure

Similar function, different structure

Embryos

Unrelated organisms show similarities in embryotic stages support common ancestor

Microevolution

pertains to evolutionary change within pop

Population genetics

Feild of biology studying diversity of population at level of gene

Hardy-Weinberg equilibrium

Stable non-evolving state, no mutations, no migration, large gene pool, random mating, no selection

Gene flow

Movement of alleles between population

Reproductively isolated

incapable of interbreeding, first stage to form new species

Genetic drift

change in allele frequencies of a gene pool due to chance events, small gene pools more affected

Bottleneck effect

type of genetic drift, loss of genetic diversity due to natural disasters

Founder effect

genetic drift type, genetic variation lost when few individuals break from a large population

Nonrandom mating

Doesn’t cause allele frequencies to change, affects how alleles in gene pool assort into genotypes

Assortative mating

when individual choose mate w/ preferred trait, certain genotypes more frequent.

Polygenic

controlled by many genes

3 types of natural selection

stabilizing, directional, and disruptive selection

Stabilizing selection

occurs when intermediate phenotype is most adoptive for environmental conditions, narrows phenotype range

Directional selection

When extreme phenotype favored, distribution curve shifts towards one of extremes, changes frequency of phenotype, when population is adapting to the environment,

Disruptive selection

When 2 or more extreme phenotypes favored over intermediate phenotype

Sexual dimorphism

Males and females differ in size/traits

Speciation

splitting of 1 or more species

Morphology

New species w/ difference in appearance

Morphological species concept

Species distinguished from each other by 1 or more distinct physical characteristics (diagnostic traits)

Cryptic species

Species that look almost identical but different in other traits

Evolutionary species concept

Relies on identification of certain morphological traits to distinguish one species from another

Phylogenetic species concept

Evolutionary family tree used to identify species based on common ancestors

Biological species concept

relies on reproductive isolation to identify different species

Prezyotic isolating mechanisms

prevent reproductive attempts/make it unlikely fertilization is successful

Habitat Isolation

2 species occupy different habitats are less likely to meet/reproduce

Temporal isolation

related species can live in same location by reproduce at different times of year

Behavioral isolation

Have courtship patterns allow male/females recognize each other

Gamete isolation

Gamates may not fuse

Postzygotic isolation mechanisms

after formation of zygote, prevent hybrid offspring from developing and reproducing as hybrid infertile

Allopatric speciation

Eventual results of population separated by geographic/physical barrier

Reinforcement

Given to process of natural selection that reinforces reproductive isolation

Sympatric speciation

Speciation in absence of a geographic barrier

Autoploidy

diploid plant produces diploid gamates bc nondisjunction in meiosis and fuses w/ haploid to make a sterile triploid plant

Polyploid

Sympatric speciation w/ chromosomes beyond 2n

Alloploid

Occurs when 2 different but related species of plant hybridize, followed by chromosome doubled

Adaptive radiation

type of speciation occurring when single ancestral species rapidly gives rise to variety of new species adapting to environment

Convergent evolution

When biological traits evolve in 2 unrelated species as result of exposure to similar enviornment

Prezygote barriers

prevent mating/hinder fertilization

What are the prezygotic barriers

Habitat isolation, temporal, behavioral, mechanical, and gametic isolation

Postzygotic barriers

hybrid inviability/fertility/break down

Adaptive radiation

many new species arise from single common ancestor

Gradulism

common ancestor, slow constant change

punctured equilibrium

Long periods of stasis punctured by sudden change seen in fossil record

LUCA

last universal common ancestor to all organisms that live/have lived

4 stages of origin of life

Organic monomers evolve from inorganic ones, organic polymers, protocells, living cells

Protocells

polymer enclosed in membrane

Iron-sulfur world hypothesis

Dissolved gasses emitted from thermal vents (CO2) would pass over iron and nickel sulfide minerals

RNA-first hypothesis

Only macromolecule RNA needed to progress toward forming first cell

Mitochondria/chloroplast

size within range of bacteria, have own DNA/proteins, divide by binary fussion, different membrane

Index fossils

identify deposit made at same time

Genozoic

Significant mammalian extinction

Mesozoic

Mass extinction of plants/animals

Paleozoic

great dying

Precambarian

Earth forms

Fossil record

Used to reconstruct history

Incomplete record

Many organisms not preserved, fossil destroyed or not found

Relative dating

Uses order of rock strata to determine relative age of fossils

Radiometric dating

Measure decay of radioactive isotopes in layers of fossils are found

Half life

Number of years for 50 percent of original sample to decay

Major periods end/begin

end with mass extinction, begin with adapative radiations

Adaptive radiation

New species arise from single common ancestor, happens when few organisms go to new areas and environment changes

Systematics

Classifying organisms and determine evolutionary relationship

Tools to determine evolutionary relationships

Fossils, morphology, molecular evidence/DNA

Phylogenetic tree

Shows evolutionary history of group of organisms, based on biochem evidence

Cladograms

dosn’t show evolutionary relationship, shows relative adaptations arose, or how useful traits are

Glade

group of species including ancestorial species

Shared derived characteristics

Used to construct cladograms

3 domains

bacteria, archaea, eukaryotic

Elements across all 3 domains

DNA/RNA carriers of genetic info, universal genetic code, conserved metabolic pathways

Conserved elements in Eukaryotes

Cytoskeleton, membrane-bound organelles, linear chromosomes, endomembrane system

Maximum parsimony

Use simplest explanation to construct phylogenetic tree

Molecular clocks

Measure evolutionary change based on regions of genome that appear to evolve at constant rate

Horizontal gene transfer

Movement of genes between domains, exchange of transposable elements, plasmidsm infection