Evolution Quiz

Evolution

change in a population over time

Darwin’s postulates

environment, competition, variation, and artifical

environment postulate

any modification b/c of environment aspects (food availability/type, climate/weather changes, and natural disasters)

competition postulate

any modification to species b/c of struggle for resources (predation and intraspecic), diseases, and fitness

variation postulate

modifications to species b/c of genetics (inheritable changes b/c of reproductive techniques)

artificial selection

modifications via selective breeding

Genetic variation

what drives differences within population?

macrovariation

changes over long periods of time (ex. reptiles- birds)

microvariation

small changes over fast period (ex. bacteria and finch beaks)

Mutations, sexual reproduction, and gene expression

What are the three reasons for genetic variation

mutations

unpredictable changes, can be detrimental or beneficial, and most common in bacteria/viruses

sexual reproduction

different gamete combinations, crossing over/independent assortment, and low mutation rates b/c of checkpoints, telomeres, and enzymes

genetic duplication

mostly harmful if not occuring in plant, can expand genomes, and can create new species (b/c self-fertilization)

Comparative Anatomy, fossils, biogeography, and molecular comparisons

What is the evidence for evolution?

Homologous structure, analogous structure, and vestigial strucutures

What are the different types of comparative anatomy?

Homologous structure

anatomically similar but different functions + usually b/c of divergent evolution (mammalian forelimbs + arthropod appendages)

divergent evolution

interbreeding species diverged into two or more evolutionary groups (common ancestor)

convergent evolution

species occupy similar ecological niches and adapt in similar ways in response to similar selective pressures (do not share ancestor)

analogus structure

anatomically different but similar function b/c of convergent evolution (shark + dolphin tails, vertebrae vs invertebrate eyes, limb regneration

vestigial structures

had role in ancestor but no longer has use; usually gets smaller b/c cannot remove (whales + boa constrictors having hip bone + appendix, tailbones in apes/humans, and goosebumps)

fossils

direct evidence of change over time, shows intermediates btwn extict and extant or groups, and can show transitions in body forms (ex. aracharoptrxy/birds, tiktaalik/amphibian-reptile, and horses + whales)

Biogeography

past + present distribution of species, island species most closely related to mainland, fossil distribution b/c of tectonic plates, and leads to closely related species on different continents (ex. monkeys in S America, africa, and asia; jaguar + leopard; camels form N America to Africa/Asia + S America

Molecular Comparisons

genetic similarities in DNA/AAs, can be used to create phylogenic trees + infer when spieces diverged, supported + moderized Darwin’s Theory (Ex. humans + chimpanzes diverged 6mya and share 99% of DNA)

biological species concept

populations have members capable of producing viable offspring

phylogenic species concept

species in a single line of decent form + stay that way (doesn’t get supported well)

Anogenic + Cladogenic

What are the two forms of speciation?

Anogenic

gradual change of one species to a new form, # of species doesn’t change

Cladogenic

two or more species share an ancestor; alloptric and sympatric

allopatric

geographic isolation b/c of different pressures and common in islands/land bridges

sympatric

speciation occurs in close proximity, polyploidy in plants (extra genes); (song birds and cichlids w/ various species in lake victoria)

allopatric and sympatric

what are the types of cladogenic?

reproductive isolation

how a species remains pure

prezygotic and postzygotic

2 categories of reproduction isolation

habitat/ecological, temporal, behavioral, mechanical, and gametic isolation

what are the types of prezygotic barriers?

hybrid invariability, hybrid breakdown, and hybrid sterility

What are the types of postzygotic barriers?

habitat/egological isolation

temporal isolation

timing of mating (ex. plants fertilizing at different times)

behavioral isolation

different mating rituals (mainly in birds)

mechanical isolation

physically different and won’t work

gametic isolation

mating occurs but eggs and sperm cannot fuse (common in fish)

hybrid invariablity

doesn’t make it past embryonic phase and most common (bulldog and leopard frogs)

hybrid breakdown

hybrid survives but offspring have reproductive issues (sunflowers)

hybrid sterility

hybrid cannot reproduce (mules, zebroids, liger, and tigons)