Biology 2 - Unit 4

Ecology

Ecology

the study of the interconnections and interrelationships between organisms and their environment

Ecology can study relationships between the ___________ and ____________ species

same; different

Abiotic

non-living

Levels of organization

the different levels at which biology is studied

The levels of organization are…

atoms, cells, organisms, population, community, ecosystem, biosphere

Nested hierarchy

when the larger part of a system are made up of the smaller parts, levels of organization is an example of this

Sample/ population size (N)

the size of the sample or population being studied

Lambda (λ)

population growth rate, the ratio of population sizes in a closed population, (Nt+1/Nt)

Population dynamics

changed to a population over time, works in a cycle, growth decline stability and recovery

Carrying capacity (k)

the largest the population can stably be

Population size and dynamics are controlled by _________ factors, ________ _________ factors, and ____________

biotic; abiotic environmental; dispersal

BD model

the birth and death model, only for a closed population, the current population- those who died + those born

BIDE model

birth immigration death emigration, current population + birth +immigration - death - emigration

Birth rate (b)

the number of people born / population

Death rate (d)

the number of deaths / population

Population dynamics are determined by _______ _ ________

birth v. death

Community

a group of multiple species living together at the same place and time

Geographic range

an area made up of multiple communities

Intraspecific interactions

interactions between members of the same species

Interspecific interactions

interactions between members of different species

Predation

common negative direct interaction in a community, hunting

Competition

common negative direct interaction in a community, fighting for the same food

Indirect interactions

effecting another species through forces where they do not interact

Ecosystems

communities with physical, chemical , abiotic interactions, and physical factors

Physical features

land and geography, studied by geologists geographers and climatologists

Anthropogenic ecosystems

ecosystems where humans are major influences of physical and abiotic features

Anthropogenic ecosystems

ecosystems where humans are major influences on physical and abiotic features

Agroecosystems

ecosystems where human agriculture occurs

Succession

the series of changes in ecosystem conditions that occur after a major abiotic or biotic event or change, like a disturbance

Disturbances

major changes to an ecosystem that stress species, typically much of the biomass is changed or killed, typically kill much of a communities foundation species

Foundation species

species that play a major role in a community by providing habitat, food, etc. for many species

Human disturbance

a large change done by humans to a community

Clearcut

a human disturbance, all trees cut down and usually left to rot

Slash and burn

a human disturbance, a farming technique where an area is cut down and burned to release nutrients into the soil

Selective logging

a human disturbance, removal of just the valuable trees, leaves other trees intact

Primary succession

succession from a completely new substrate, starts with no biomass, ex. after a large volcano, fire, or glacier retreat

Nitrogen fixing plants

usually the first plants of a primary succession, use nitrogen to create their own fertilizer

Secondary succession

disturbances leaving residual biomass below or above ground

Pulse disturbance

a pulse of damage, death, or loss of biomass to a community

Press disturbance

a disturbance that does not allow succession to take place, ex. continuously grazing a field

Habitat mosaics

constant press disturbance that only allows some areas to undergo succession, creates a fragmented looks

habitat fragmentation

little pieces of habitat left behind by human press disturbances, leaves gaps between small fragments

Habitat edges

the outside line of fragmented habitats, causes edge effects

Soil aeration

the process of increasing air and water flow in the ground

Ecosystem engineer

things with pervasive qualities, alter the physical environment, ex. humans and elephants

Savanna

a grassland ecosystem with trees and shrubs

Herbivore outbreak

a biotic disturbance, many herbivores, eat and kill many trees and plants