Unit 5 BIO100 Exam

what’s ecology

study of interactions between organisms & their environments

ecology is closely related to which fields

physiology, evolution, genetics, & behavior

what’re biotic factors

all living organisms in an environment

what’re abiotic factors

nonliving environmental components (temp, light, water, minerals, air)

what mainly influences the distribution of life on Earth

differences in abiotic factors

what’s a biome

a major aquatic or terrestrial life zone, defined by vegetation (land) or physical environment (water)

what % of Earth’s surface is aquatic biomes

about 75%

list freshwater biomes

lakes, streams, rivers, wetlands

list marine biomes

oceans, intertidal zones, coral reefs, estuaries

what characterizes tropical forests

warm temps, high rainfall, 11-12 hr days, high species diversity

what characterizes savannas

grass + scattered trees, warm, seasonal rainfall, fires, many herbivores

what characterizes deserts

driest biome, <30 cm rainfall, extreme temps, nocturnal animals, water-storing plants

what characterizes chaparral

mild wet winters, hot dry summers; fire-adapted plants; many nocturnal animals

what characterizes temperate grasslands

mostly treeless, 25-75 cm rainfall, drought/fires, fertile soil, grazers (bison)

what characterizes deciduous forests

midlatitudes, enough moisture for large trees, seasonal leaf loss, animal adaptations for winter

what characterizes coniferous forests

largest terrestrial biome, evergreen cones, cold climates, needle leaves, overwintering animals

what characterizes tundra

arctic region, permafrost, cold + wind, low plant/lichen, migratory animals

what does competition mean in species interactions

(-/-)

both populations are harmed

what does commensalism mean in species interactions

(+/0)

one organism benefits, while th other is unaffected

what does mutualism mean

(+/+)

both species benefit

what does predation, herbivory, & parasitism mean

(+/-)

one benefits, one is harmed

what happens in interspecific competition

population growth is limited by competitors

what adaptations help prey avoid predators

camouflage, warning coloration, mimicry

how do plants defend against herbivory

thorns, spines, chemical toxins

what’s a trophic level

a level in a food chain where organisms get their energy

order of trophic levels

producers → primary → secondary → tertiary → quaternary consumers

how much nrg is transferred between levels

~10% (90% lost)

scavengers

eat carcasses

detritivores

eat decaying material

decomposers

convert organic material to inorganic material

what does evolution favor in organisms

those that adapt best to their environment survive & reproduce

what’s biogeography

study of where species live & how they got there

what idea did Darwin propose about species change

descent w/ modification, species change over generations due to environment

why do some individuals survive better

they have heritable traits that help them adapt to the environment

what results over generations

favorable traits increase in the population (evolution)

five main lines of evidence for evolution

fossil record, biogeography, comparative anatomy, comparative embryology, molecular biology

what’s fossil record

ordered fossils in rock layers showing how organisms changed over time

how does relative dating work

fossil age based on its position in rock layers

four mechanisms of evolution

mutation, genetic drift, gene flow, & natural selection

what’s a mutation

random change in DNA, the og source of genetic variation

what’s genetic drift

random changes in allele frequencies, esp in small populations

what’s the bottleneck effect in genetic drift

a sharp reduction in population size (due to bottleneck event) reduces genetic diversity

what’s the founder effect in genetic drift

a new population founded by a few individuals has limited genetic variation (the Amish)

what’s gene flow

movement of genes between populations through migration

what does gene flow do

it increases genetic diversity & reduces differences between populations

what does natural selection act on

phenotypes (observable traits)

which mechanism of evolution is always adaptive

natural selection

what must be true for natural selection to occur

variation, heritability, and differences in survival/reproduction

what’s sexual selection

choosing mates based on traits that improve reproductive success

what’s directional selection

favors one extreme phenotype

ex: breeding turkeys w/ larger breast muscles

what’s disruptive selection

favors both extremes, not the middle

ex: small fish hide in crevices & large fish win territory, so medium fish die off

what’s stabilizing selection

favors intermediate traits

ex: medium birth weights have highest survival

what’s speciation

formation of a new species

what’s allopatric speciation

new species form due to geographic isolation

what’s sympatric speciation

new species form w/o geographic seperation

how do we know speciation has occured

two groups can no longer interbreed

what often causes sympatric speciation in plants

errors in cell division leading to polyploidy (extra chromosomes)

what’re three components of biodiversity

genetic diversity, species diversity, and ecosystem diversity

four major causes of biodiversity loss

habitat destruction, invasive species, overexploitation, & pollution

what threatens habitats & leads to species loss

agriculture, urban development, forestry, & mining

what’s habitat fragmentation

breaking large habitats into smaller, isolated patches

harmful to biodiversity

how do invasive species harm ecosystems

they compete with, prey on, or parasitize native species

what’s overexplotation

harvesting wildlife at rates faster than populations can recover

how does pollution contribute to biodiversity decline

it harms air & water quality, affecting species survival

what causes acid rain

sulfur dioxide combining w/ water in the atmosphere

why is petroleum pollution dangerous

it’s persistent, toxic, & hard for microbes to break down

what does systematics study

classification of organisms & their evolutionary relationships

what’s taxonomy

naming, identifying, & classifying of species

what are three domains of life

bacteria, archaea, & eukarya

which domains are prokaryotic

bacteria & archaea

which domain contains protists, plants, fungi, & animals

eukarya

list classification levels from broad to specific

order → family → genus → species

how does the biological species concept define a species

a group whose members can interbreed & produce fertile offspring

what’s conservation biology

science focused on understanding & preserving biodiversity

what’s restoration ecology

returning degraded ecosystems to their natural conditions

ex; recycling

what’s bioremediation

using organisms to remove pollutants from environments

why do animals communicate

to survive, find mates, warn of danger, defend territory

visual communication

body movements/color ex: peacock feathers

tactile communication

touch

chemical communication

pheromones/scents

acoustic communication

sound signals

what does inclusive fitness include

an animal’s total success in passing on genes

direct fitness

producing own offspring

indirect fitness

an organism's reproductive success as measured by the success of its genetic relatives

what’s kin selection

a type of natural selection where individuals will sacrifice their own lives in an effort to save closely related organisms

what’s altruism in animal behavior

helping another individual at a cost to oneself

ex: worker bees protect the hive but don’t reproduce

what’s convergent evolution

unrelated species evolve similar traits due to similar environments

creates analogous structures: same function, different origin

ex: bird vs. insect wings

what’s divergent evolution

related species become more different over time because they adapt to different environments

ex: Darwin’s finches evolved many beak shapes based on food sources

what’re vestigial structures

remnants of traits that were useful to ancestors but not needed now

ex: human tailbone; embryos show tails + gill-like pouches

what does comparative embryology show

early development stages of different species look similar, shows common ancestry

ex: all vertebrate embryos have tails & pharyngeal pouches early on

how do scientists determine evolutionary relationships

by comparing DNA, genes, & proteins across species

what does descent w/ modification mean

species change over generations, but share common ancestors

ex (DNA similarity to humans: chimp (99.5%), mouse (88%), chicken (75%), fly (60%)