Evolution/natural selection

Evolution

change in genetic composition of a population overtime

-descent with modification

-Genetic composition→ allele frequency

Heritable

traits are passed to offspring via sexual reproduction

population

• group of organisims of the same species living in the same geographical area at the same time

Species

• individuals that can interbreed and reproduce but they dont interbreed with other species

Time

evolution is observed over many generations, but it is happening continuously

Darwin natural selection

• evolution is a change in allele frequencies within a population

• occurs by mutation, genetic drift, migration and natural selection

Mutation

• alteration of a base pair in the drift of an individuals gamete producing cells that changes an alleles frequency

Genetic drift

• a random change in allele frequencies, unrelated to any alleles influence on reproductive success

migration

• individuals move to a new population

natural selection

• change occurs when individuals with one version of a heritable trait have greater reproductive success than individuals with a different version of trait

root

the common ancestor of all species in the tree

tips

represent the descendant taxa

nodes

• represent the common ancestor of these descendants that branch from it

Phylogenic tree

evidence darwin used for natural selection

• comparative anatomy, embryo development, biogeography, fossils and genetic sequencing

Homologus structures

• similarity due to common ancestry even if function is different

Vestigal structures

inherited structures that no longer serve a purpose

embryo development

no outside pressure, any features are inheirited

Biogeography

geographic distribution of species

• species that are closer in distance are closely related

• continental drift and plate tectonics

Transition Fossils

• links that demonstrate common ancestry

• reconstruct what ancient species looked like

Molecular data

DNA comparisons: similar DNA and protein sequences are inherited from common ancestor

Gene pool

the sum of all the individuals genes in a given population

Allele frequency

the frequency of an allele is the number of occurrences of that allele in that population

Population bottleneck

• population is drastically reduced(natural,catastrophe)

Founder effect

if a subgroub starts a new colony that population will have different allele frequencies than the starting population

Survival of the fittest

• those who are better adapted for intermediate, local enviornment allowing them to stay alive and reproduce

Variation

• individuals in the same species are different from each other

Morphiological differences

size, shape,color

physiological differences

• occurance and metabolic rate

Behavioral differences

• predator avoidance behaviors and courtship displays

Fitness

• individuals whose traits are better adapted to the enviornment produce more offspring

• is survival and reproductive success

Adaptations

• are heritable features that improve an organisms ability to survive and/or reproduce

Evolution

• better adapted traits increase in frequency within a population over generations

Directional selection

• trait moves in one direction or another

Stabilizing selection

selective pressure which puses the population to fit within an average

Disruptive selection

• extreme on both sides

How did darwi discover natural selection

• found finches on the galapagos island had slightly different features adjusted to their enviornment

Species

• groups of actual or potential interbreeding populations which are reproductively isolated from other such groups

Prezygotic Barriers

• prevents mating between popualtions due to physical complications

Postzygotic barriers

• prevent fertile offspring after mating

Allopatric speciation

• physically split

Sympatric speciation

species split in same location

Homology

• same trait as ancestor

Homopalsy

• similar trait as species but not inherited

Apopmorphy

• opposed to common ancestor

Symplesiomorphy

• same/inheirited from common ancestor

autapomorphy

• unique trait only one person has

Microevolution

• change in allele frequencies over one or a few generations

Macroevolution

• accumulated effect of microevolution over time

Adaptive Radiation

• the diversification of a small number of species into a much larger number of species

• population of one species invade a variety of new habitats

Mass extinction

• if competition is suddenly eliminated, the remaining species can rapidly diversify

Colonization events

• moving to a new location and essentially colonizing

Evolutionary innovation

• with the evolution of an innovative feature that increases fitness, a species can diversify

Organization of species

Domain → Kingdom→ phylum→ class→ order→ family→ genus→ species

Domains

Eukaroytes, Bacteria, Archea

Kingdoms

Protisa, fungi, plantae, Animalia

Phylum, class, order, family, genus

• narrow down description of critters to be more specific

Species

• most specific description of critter

Bacteria

• benefical, harmful or neutral

• oldest, prokaryotic

• single celled

• Broader diversity

Archea

• extermophiles(thrive in extreme environments)

• middle

• prokarytic

Eukaryotic

• contains organelles

• youngest

• includes humans and living organisims

Protists

very diverse

Fungi

• heterotrophs(consumes for nutrients, mostly multicellular)

Plants

• mostly multicellular

• autotrophs

• cell walls

Animals

• heterotrophs

• mostly multicellular