AP Classroom Units 7+8

this is stuff Mr. lynch didn't talk about at all (mostly)

what factors influence natural selection

• environmental stability

• genetic variation

• adaptations

• fitness

structural evidence providing support for the common ancestry of all eukaryotes

• membrane bound organelles

• linear chromosomes

• introns

how do pathogens contribute to the evolution of other populations

as pathogens evolve, the phenotypes selected for in host populations changes

out-groups

the lineage that is least related to the remainder of the organisms

RNA World Hypothesis

the theory that RNA could have been the earliest genetic molecule

how do organisms exchange information

• visually, audibly, tactile, electrically, chemical signalling

• communicate dominance, food, territory

• ensures reproductive success

how does signalling behavior produce changes in others behavior and affect reproductive success

signalling increases the survival chance of members of a population, increasing the likelihood of reproduction

what behaviors does natural selection favor

innate and learned behaviors that increase survival and reproductive fitness

how does cooperative behavior impact individual fitness and population survival

it increases it

metabolic rate

the amount of energy expended by an animal in a specific amount of time

trophic level

the position an organism occupies in a food chain

food chain

a diagram that shows the direction of nutrient and energy transfer between organisms

food web

a diagram that consists of many interconnected food chains

autotrophs

• organisms that capture energy from physical or chemical sources in the environment

• photosynthetic organisms get energy from light

• chemosynthetic organisms get energy from small, inorganic molecules present in the environment

heterotrophs

organisms that capture present in carbon compounds produced by other organisms

endotherm body temperature regulation

thermal energy is gained by metabolism (heart rate, fat storage, muscle contractions)

ectotherm body temperature regulation

rely on behaviors to regulate temperature (moving in/out of sun)

reproductive strategies in response to energy availability

• many offspring at once

  • less energy efficient

  • common in unstable environments where resources are scarce

• few offspring at once

  • more energy efficient

  • common in stable environments

relationship between metabolic rate and organism size

typically, the smaller the organism, the higher the metabolic rate

impact of net energy gain

energy storage or growth

impact of net energy loss

loss of mass, and ultimately death

what factors influence population growth

• age at reproductive maturity

• number of offspring

• frequency of reproduction

• offspring survival

• population size

population

organisms of the same species in a particular area who usually interbreed with each other more often than they do with individuals of another population

what leads to exponential population growth

reproduction without constraints, which occurs under idea conditions when resources are abundant

density-dependent factors

factors whose effect on population size relies on population density

• competition

• territoriality

• disease

• predation

density-independent factors

factors that affect population size regardless of the population’s density

• natural disasters

• pollution

logistic-growth model

• population growth that starts slow, immediately followed by exponential growth, ending with ha relatively stable maximum growth

• illustrated by an s-shaped curve

what causes population density to exceed carrying capacity

when resources are abundant, populations can grow too large, but limiting factors will always bring them down

what causes a population to display a logistic growth model

this is typically the result of the imposition of density dependent and independent factors

community

• a group of species living in the same location and interacting

• described/measured based on species diversity and composition

species diversity

the variety of species and quantity of individuals in each species within a community

species composition

the identity of each species in a community

trophic cascade

the negative impact the removal or decline of a key species has on trophic levels

niche partitioning

a decrease in competition over limited resources because two similar species are accessing a resource in different ways

what determines whether communities change over time/how populations access matter and energy

population interactions (positive, negative, neutral)

how are relationships among populations characterized

positive, negative, neutral

these can be modeled

what types of interactions can drive population dynamics

• competition

• predation

• parasitism

• mutualism

• commensalism

keystone species

• species that the community structure depends on

• small populations that are disproportionate to their impact on the environment

• ecosystem often collapses with their removal

how does species diversity in an ecosystem influence the organization

• structure is stabilized with diversity

• changes in diversity can cause short or long term structural changes

what factors maintain ecosystem diversity

• keystone species

• essential abiotic factors

  • light

  • climate

  • water

  • nutrients

• essential biotic factors

  • producers

  • consumers

adaptation

a genetic variation favored by selection

invasive species

a nonnative species that harms the community it is introduced to

how do invasive species impact ecosystem dynamics

the new species can exploit a new niche free of predators/competitors or outcompete other organisms

what human activities lead to changes in ecosystem structure or dynamics

• urbanization

• deforestation

• erosion

• extinction

• pollution

• climate change

• spread of disease