ecology and evolution

exam 5 BCOR

ecology

the scientific study of the interactions between organisms and the living and nonliving components of their environment

evolution

the scientific study of changes in heritable characteristics of organisms over successive generations

organismal ecologists

explore morphological, physiological, and behavioral adaptations

adaptations

heritable traits that increase fitness of an individual in a particular area

population ecologists

focus on how the number and distribution of individuals in a population change over time

community ecologists

study the nature and consequences of the interactions between species

biological community

consists of the species that interact with one another within a particular area

ecosystem

consists of all the organisms in a particular region, along with abiotic components

ecosystem ecologists

study how nutrients and energy move among organisms and through the surrounding atmosphere, soil, and water

ecological niche

the range of conditions that a species can tolerate and the range of resources that it uses; by-product of past and present biotic and abiotic factors

biosphere

the thin zone surrounding the earth where all life exists

global ecologists

focus on the effects of human impacts on the biosphere

abiotic factors

examples are rainfall, sunlight, disturbance frequency, salinity, nutrient availability, and temperature

biome

a large terrestrial or aquatic region characterized by abiotic characteristics, largely temp and precipitation, and dominant types of vegetation

climate, light and nutrient availability, salinity

3 determinants of where a species lives

biogeography

the study of how organisms are distributed geographically and throughout geological time

range

geographic distribution of a species as determined by biotic and abiotic factors

temperature and precipitation

range is determined at a global scale by

microclimate

range is determined at a local scale by

density

individuals per unit area/volume

direct counts

useful for small/easy to count populations

quadrat sampling

useful for plants and sessile animals, subsample and extrapolate to estimate entire population size

mark recapture

useful for wildlife, capture a random sample and tag, capture a second set and use an equation to solve total population size

remote sensing

for elusive, endangered, or very large-ranged animals using SCAT, camera traps, and satellites

dispersion patterns

an individual’s arrangement within a population may be one of three…

random dispersion

if the position of each individual is independent of the others

clumped dispersion

if the quality of the habitat is patchy or the organisms are social

uniform dispersion

if negative interactions occur among individuals that space them out evenly

birth and immigration

these two processes add to the number of individuals in a population

death and emigration

these two processes remove from the number of individuals in a population

demographers

study age structure, birth and death rate, survivorship, and generation time to understand a population

cohort

a group of individuals of the same age that can be followed through time

survivorship

the proportion of offspring that survive on average to a particular age

type 1 survivorship curve

survivorship throughout life is high and most individuals approach the natural life span of the species (ex: humans)

type 2 survivorship curve

most individuals experience relatively constant survivorship over their lifetimes (ex: songbirds)

type 3 survivorship curve

results from high death rates early in life with high survivorship after maturity (ex: sea turtles)

fecundity

the number of female offspring produced by each female in the population

age-specific fecundity

fecundity per age class

net productive rate

indicates if population is increasing or decreasing, represented by R

R=1 means population is stable

fitness trade-off

occurs because every individual has a restricted amount of time and energy at its disposal (resources are limited)

high fecundity

organisms tend to grow quickly, reach sexual maturity at a young age, and produce many small eggs

high survivorship

organisms tend to grow slowly, invest their energy and time into traits that reduce damage from enemies, increase their own ability to compete for resources, and produce fewer offspring that are larger

semelparity

one time reproduction

iteroparity

repeated reproductive events

exponential growth

the accelerating increase that occurs when growth is unlimited

J-shaped curve

shape of curve when plotted on a graph that is because the population is changing at a rate proportional to its current size

density independent

in exponential population growth, population size does not limit growth rate

logistic growth

when population density gets very high, population’s per capita birthrate decreases and per capita death rate increases

S-shaped curve

shape of curve when plotted on a graph that is because early growth is exponential but levels off when approaching carrying capacity

carrying capacity

the maximum number of individuals in a population that can be supported in a particular habitat over a sustained period of time

density dependent

how does logistic growth correlate with population density

abiotic factors

factors not included in logistic or exponential growth curves because they are random events not predicted by models

population momentum

sustained exponential growth over a long period of time (humans)

community ecology

examines the effect of interspecific interactions on structure and organization

species interactions

relationship between 2 species are described by how the affect a species

(- / 0 / +)

commensalism

individuals of one species benefits while the individuals of another species are neither harmed nor helped (+ / 0)

consumption

individuals of one species eats or absorbs nutrients from another (+ / -)

predation

form of consumption where the predator kills or consumes all or most of the prey, typically carnivores

herbivory

form of consumption where one organism consumes plant tissue but typically not the entire organism

parasitism

form of consumption where an organism lives in or on the host and takes resources from it, usually not fatal with one exception

coevolutionary arms race

results from predator and prey interacting over time, repeating cycle of reciprocal adaptation

coevolution of predator and prey

major driver of evolutionary change, leads to diversity of defensive adaptations

mutualism

fitness benefits to both species, very common in nature (+ / +)

competition

lower fitness for both individuals involved (- / -)

intraspecific competition

competition between members of the same species, density dependent

interspecific competition

competition between different species that use the same limiting resources

resources partitioning

differentiation of niches that enables similar species to coexist in a community

character displacement

changes in species’ traits that enable them to exploit different resources, makes niche differentiation possible

species composition

list of species present in a community

species richness

number of species present in a community

species evenness

abundance of each species in a community

diversity stability hypothesis

higher biodiversity leads to greater ecosystem stability

biomass

total mass of all organisms, increases with diversity

keystone species

exert strong control on a community by their pivotal ecological roles, disproportionate influence on diversity and abundance of other species in their community through direct and indirect effects