apbio evolution

adaption

-traits of organisms that closely fit their environments -->from natural selection

biodiversity

-variety of life on earth (species, ecosystems, genes) -biological diversity

phylogenic tree

-how evolution can be modeled as a branching tree w/ a common trunk and branches splitting off shared features-inheritance from common ancestor -evolutionary tree

node/root in tree

nodes-points on tree where species splits into two root-base of tree, representing common ancestor of all groups

natural selection (what you need)

1)variation in population 2)competition for resources 3)differential reproduction/survival (some traits help individuals survive) 4)pass on traits (inheritance key) NOT RANDOM

convergent evolution

process by which 2 unrelated species evolve similar traits in response to similar environmental changes Don't share common ancestor -same body plan (bc envoronmen)

artificial selection

process -humans select for traits

sexual selection

promotes traits that increase an individual's ability to find + attract mates

stabilizing selection

favors intermediate phenotypes -acts against extreme phenotype -maintaining the status quo

directional selection

favors one extreme over the other -phenotype shifts in one direction

distruptive selection

2 diff favorable extreme phenotypes -acts against intermediate phenotypes

importance of variation in population survival

Genetic variation -increases a population's ability to survive changing environments. Natural selection -favors individuals with traits that help them adapt. Diversity -reduces the risk of extinction from disease or environmental changes. More variation = higher chances of some individuals surviving threats. Essential for evolution, allowing species to adapt over time.

miller urey experiment

tested how life's building blocks could have formed on early Earth -Simulated early Earth's conditions to test if organic molecules could form. -Used a mixture of water (H₂O), methane (CH₄), ammonia (NH₃), and hydrogen (H₂)—thought to be in Earth's early atmosphere.Applied electric sparks to mimic lightning. -After a few days, they found amino acids, essential for life, had formed. -organic molecules can form naturally, supporting theories about the origin of life.

RNA world hypothesis

RNA was the original info-storage molecule in the earliest forms on life on Earth -bc RNA has both DNA + protein properties, -and involved in key cellular processes

first cells on earth

prokaryotic -cell lvl structures might have formed spontaelously on earth -anerobic-w no oxygen bc early earth had little to none liposomes(form, break, and reform)-could have captured selp-replicating RNA-->self rep RNA encapsuled by liposomes numerous times-->prototype "first cell" made

homologous

-Structures that are similar in structure but may have different functions--> shared ancestry. ex. The forelimbs of humans, bats, whales, and cats have the same bone arrangement but serve different purposes (grasping, flying, swimming, walking). Evidence for Evolution: Suggests that species with homologous structures evolved from a common ancestor.

analogous

-Structures with similar functions but different evolutionary origins ex. Wings of birds, bats, and insects—all used for flying but evolved independently. No Common Ancestor: These structures arise due to convergent evolution, where different species adapt to similar environments.

radiometric dating

-method used to determine the age of rocks and fossils by measuring the decay of radioactive isotopes(unstable form-as it breaks down releases radiation becoming more stable. -Unstable radioactive isotopes (parent) decay into stable isotopes (daughter, result) at a constant rate. -compare amt of radioactive isotope w/ amt of its decay product half-life—time it takes for half of the parent isotope to decay. C14-most common (common element, date wide variety of objects)

invasive species

non-natural species that become established in new ecosystems

vesitigial structures

-traits that were once useful or functional but are no longer -tend to be reduced in size or function ex. hip bone in whales (since evolved from land animals-->water)(small but still present) ex. appendix of humans -no clear function, minor role in immune system

molecular clock

time 2 species separated and about of genetic divergence

genetic drift

random event that changes the gene pool

gene pool

Combined genetic information of all the members of a particular population

bottleneck effect

large population suddenly reduced to a few individuals -sudden environmental change small subset now becomes gene pool This makes the population more vulnerable to diseases and changes in the environment.

founders effect

small subset of individuals find/establish new population isolated from OG population -less genetic variation This can lead to higher frequencies of certain traits or genetic disorders in the new population.

migration/gene flow

individuals move in/out of a population to another population, carrying genes w them Increases genetic diversity within a population, as it adds new genes or alleles.

fitness

-fit enough organism's ability to survive, reproduce, and pass on its genes to the next generation. -don't have to be the fittest—JUST SURVIVE

divergent evolution

-common ancestor -body plans diverge overtime-due to different environments or selective pressures. ex. Darwin's finches in the Galápagos Islands started from a common ancestor but evolved different beak shapes based on the types of food available on each island.

Interasexual selection

A direct competition among individuals of one sex ex. males competing for female

intersexual selection

Selection whereby individuals of one sex (usually females) are choosy in selecting their mates from individuals of the other sex; also called mate choice.

balancing selection

natural selection that maintains two or more phenotypic forms in a population -heterozygote advantage -Instead of one allele becoming dominant, both alleles are favored at different times or in different circumstances. -keeps genetic diversity high in a population. ex. :Sickle cell anemia: Individuals with one sickle cell allele (heterozygotes) are resistant to malaria, while those with two normal alleles are not. In areas where malaria is common, this trait is favored, maintaining both alleles in the population.

population w high lvls of genetic diversity

-result of mutations, and recombination**

5 mechanisms that bring about evolutionary change from one generation to the next

1. natural selection

2. genetic drift

3. migration

4. mutation

5. nonrandom mating -lead to change in allele frequency or genotype frequency

anatomical traits

similarities based on shared ancestry (homologous), and structural (morphological), morphological homologies—>different species have similar body parts because they evolved from a common ancestor

cellular traits

characteristics of cells that reflect evolutionary relationships and adaptations. characteristics of cells that determine their structure and function. Some key cellular traits include:

• Shape: The cell's physical form (e.g., spherical, elongated, or flat).

• Size: The cell's dimensions, which vary depending on its type.

• Organelles: Structures inside the cell, like the nucleus, mitochondria, and ribosomes, each serving a particular function.

• Function: The role of the cell in the organism, like nerve cells transmitting signals or red blood cells carrying oxygen

molecular traits

-nucleotide sequence of DNA + RNA

-amino acid sequence of proteins

genetic divergence

-difference between 2 species

-time they have genetically been isolated form eachother

molecular clock

a method used to estimate the time of evolutionary genetic divergence between species based on mutation rates in their genetic material.

-time 2 species separated + amt of genetic divergence

slowest-histoine genes (amino acid change bad for it )(evolutionary conserved)

vestigial structures

traits that were once useful and functional but are no longer

-tend to be reduced in size or function

-pseudogene

pseudogene

gene once functional but is no longer , not expressed

fossils

-remains of once living organisms

-info abt past life

-incomplete record only small fraction of organisms

fossilization

process by which fossils form

-accumilating sediments

-burial

sea-more common fossil record (shallow seafloor)

land- less common (ex. high mountains)

hard skelton-good

soft body parts less likely to fossilize.

biological molecules—> usually decay after death (DNA, proteins)

invasive species

non native species that become established in new ecosystems

adaptive radiation

single species evolves into a variety of different forms to adapt to different environments or ecological niches. This usually happens when a species colonizes a new area with diverse habitats or after a mass extinction, allowing new species to emerge that are specialized for various roles.

to get it —>change in form and function

biological species concept (BSC)

species are groups of actually or potentially interbreeding populations that are reproductively isolated form other such groups

reproductive isolation-members of one species are unable to successfully reproduce with members of another species, even if they live in the same area.

reproductive compatibility

-offspring must be fertile

2 indv- same species if available to exchange genetic material

-way to define species

BSC short comings

1)diffcult to apply-determine if offspirng fertile or not

2)can’t be applied to all organisms- based on reproduction, can’t apply to bacteria (reproduce asexually), fossil and extinct cant either

3) population of one speices may vary in extinct

reproductive isolation

mechanisms that prevent different species from interbreeding and producing fertile offspring.

barriers to reproduce bfr or after fertilization

prezygotic, postzygotic

morphospecies concept

-member of same species usually look alike

-molecular lvl B arcode of Life—>DNa seq linked to species

morphospecies concept issues

1)members of species may not always look alike (diff phenotype)

ecological niche

used to sometimes describe species

-role species plays in environment and its abiotic/biotic require

phylogenetic species concept

-memebers of species share common ancestry and fate (like a single branch)

requires:

-all members of species be descended from single common ancestor

useful:asexual species (bacteria archea)

limited: mammals descended from common ancestor BUT include many diff species not j one

prezygotic factors

act BFR fertilization and prevent fertilization to take place

-temporal isolation

-behavioral isolation

-gametic isolation

-mechanical isolation

temporal isolation

-prezygotically isolated in time

durnial, nocturnal, diff clocks

behavioral isolation

prezygotic

-individuals only mate w/ other individuals based on specific courtship rituals, songs, displays (not plants)

gametic isolation

prezygotic

-gametes incompatible, dont fuse to form fertilized egg

mechanical isolation

prezygotic

-individuals unable to mate

-prevented

postzygotic factors

act AFTER fertilization, prevents fertilized egg from developing into fertile individual

-hybrid inviability

-hybrid sterility

hybrid inviability

postzygotic

-embryo forms but doesn’t fully develop

hybrid sterility

postzygotic

-offspring produced but sterile—>viable but sterile (can’t produce offspring of their own)

speciation

pricess by which new species are produced

allopatric speciation

divergent evolution-new species arise when a population is geographically isolated from the rest of its species.

split-diff mutation occur

single pop, isolate and split

2 ways

1)disperal-individuals colonize distant place far from main pop

2) vicariance-geographic barrier arises in pop, separates

sympatric speciation

speciation occuring w/ out geographical separation

-natural selection must act strongly to counteract effect of gene flow

-changes in diet, behavior, or genetic mutations

-diff preferences

hybridization

adaptive radiation-unusually rapid diversification

-offspring reproductivelly isolated from both parents

gradualism

1 extreme of speciation

-species change slowly —>adapting to slow changing environment

extinction

-result of environmental changem predation

5 sources of evolution

populations changing overtime due to diff factors

1)mutation(variation)

2)gene flow (movement of alleles)

3)non random mating (sexual selection)

4)genetic drift (chance events)

5)natural selection (adaptive)

variation

-mutation - random changes in DNA

-sex - mixing of genes (recombination) —> new arrangements in every offspring

hardy weinburg theory

-no evolution occuring

• no mutation

• no gene flow

• no natural selection

• large popualtion

• random mating