Biology 1/2 - Ecology

Ecology

the study of the interactions of living organisms with one another and with their physical environment

organism

an individual living thing
ex. black bat

population

all of the individuals of a species that live in the same area
ex. the black bats

community

a group of different species that live together in one area
ex. black bats, worms, moss, etc.

habitat

place where an organism usually lives
ex. cave

ecosystem

the different species plus the environment; biotic factors and abiotic factors
ex. soil in that cave, light entering the cave, temperature in cave, humidity in cave, etc.

biome

major regional or global community of organisms characterized by the climate conditions and the plant communities that thrive there

biotic factors

organisms in a habitat

abiotic factors

physical aspects of the habitat

biodiversity

the assortment or variety of living things in an ecosystem

biodiversity is threatened by

pollution
global warming
habitat destruction

keystone species

a species that has an unusually large effect on its ecosystem
ex. sea otters

producers provide

energy for other organisms in an ecosystem

producer

organism that obtains energy from nonliving resources; organism that makes its own food

autotroph

another word for producer; self feeder

consumer

organism that gets its energy by eating other living or once living resources

heterotroph

another word for consumer; different feeder

producers are

basis for ecosystems energy
most rely on sunlight
almost all obtain energy from sunlight
photosynthesis

herbivores

organisms that eat only plants
ex. rabbits

carnivores

organisms that eat only animals
ex. snake

omnivores

organisms that eat both plants and animals
ex. chicken, humans

detritivores

organisms that eat dead, organic matter
ex. millipede

decomposers

organisms that break down organic matter into simpler compounds
ex. fungi and bacteria

food chain

sequence that links species by their feeding relationships

trophic levels

levels of nourishment in a food chain
ex. producer>herbivore>carnivore

producers level

level 1 on the trophic levels

primary consumers level

level 2 on the trophic levels
herbivores and omnivores

secondary consumers level

level 3 on the trophic levels
carnivores and omnivores

tertiary consumers level

level 4 on the trophic levels
carnivores that eat carnivores and some omnivores

food web

model that shows the complex network of feeding relationships and the flow of energy within and sometimes beyond an ecosystem

pyramid models

an energy pyramid shows the distribution of energy among trophic levels

10% rule

at each trophic level, the energy stored is about 10% of that stores by the level below

biomass

measure of the total dry mass of organisms in a given area
incorporated into the body of a consumer

energy pyramids

the longer a food chain, the more energy lost
diagram that compares energy used by producers, primary consumers, and other trophic levels

ecological niche

how an organism lives in its habitat
-includes all of the physical, chemical, and biological factors that a species needs to survive, stay healthy and reproduce

competition

when 2 organisms fight for the same limited resource

predation

process by which one organism captures and feeds upon another organism

symbiosis

close long term relationship between two or more species that can be beneficial or harmful
-mutualism
-commensalism
-parasitism

mutalism

both benefit
ex.ants and acacia tree

commensalism

one benefits, the other is neither harmed nor helped
ex.whale and barnacle

parasitism

one benefits, the other is harmed
ex.dog and flea

predation and competition

-promote biodiversity
-biologically diverse ecosystems are more stable than ecosystems with fewer species

competitive exclusion

when 2 species compete for the same resource, the one that is better adapted will occupy the niche while the other is either pushed into a less favorable niche or goes extinct
ex.trees

biogeochemical cycle

movement of a particular chemical through the biological and geological, or living and nonliving, parts of an ecosystem; changes of state may occur

hydrologic cycle

the water cycle

precipitation

water that falls to the earth

transpiration

type of evaporation
evaporation off the surface of leaves

elements essential for life

carbon, nitrogen, phosphorus, and sulfur

abiotic portion of the cycle

-carbon dioxide gas released in the atmosphere
-bicarbonate dissolved in water
-fossil fuel burning
-soil

biotic portion of the cycle

-cellular respiration produces carbon dioxide as a waste product
-photosynthesis uses the carbon in the carbon dioxide to make sugar
-carbohydrates stored in the plant are then used by the plant in cellular respiration or by a consumer when the plant is eaten
-decomposition also releases carbon
-fossil fuel formation
-methane gas also returns carbon to the atmosphere from decomposition processes

carbon sink or reservoirs

area that stores carbon over a long period of time

human disruption of the carbon cycle

cars, factories, and power plants burn fossil fuels and add carbon dioxide to the atmosphere

natural disruption of the carbon cycle

-forests lock carbon away, but naturally occurring forest fires release that carbon
-volcanic eruptions release carbon dioxide and nitrogen gases that overload normal cycles

bacteria

the plants and animals that have assimilated nitrogen into their bodies that then die and are broken down, return the nitrogen to the soil

decomposition

break down of organisms and return the nitrogen to the soil so plants can take it up again

ammonification

produced by bacteria during decomposition or decay processes

nitrification

converting ammonia into nitrates

population density

-number of individuals that live in a defined area
-important measure of the health of a species in an area
-fluctuations indicate that changes need to be made to keep the population healthy

population dispersion

the way in which individuals of a population are spread in an area

clumped population dispersion

individuals live close together in groups; facilitates mating, protection, and access to food and other resources

uniform population dispersion

individuals live specific distances from each other; results from territoriality and competition

random population dispersion

individuals are spread randomly

population growth patterns

population size changes, increasing, decreasing, or staying fairly constant

factors affecting population size

immigration - individuals coming into a population
births - individuals being born into a population
emigration - individuals going out of a population
deaths - individuals being removed from the population through death

exponential growth

J-curve; occurs when a population size increases dramatically over a period of time
-may occur when a species is introduced into an uninhabited area
-typical of bacteria and small animals

logistic growth

s-curve; occurs when a population begins with slow growth, followed by a period of rapid growth, before leveling off at a stable size

carrying capacity

maximum number of individuals of a particular species that the environment can normally and consistently support

population crash

dramatic decline in the size of a population over a short period of time

limiting factor

the characteristic or resource that has the greatest effect in limiting the size of a population
ex. competition, predation, parasitism, disease, unusual weather, natural disasters, human activities

succession

sequence of biotic changes in a community

primary succession

establishment and development of an ecosystem in an area that was previously uninhabited

pioneer species

typically lichens and some mosses; first organisms that live in an uninhabited area on bare rock

secondary succession

re-establishment of a damaged ecosystem in an area where the soil is exposed

nonrenewable resources

a resource that is used faster than it can be reformed
ex. oil, coal, natural gas

renewable resources

a resource that can be replace at the same rate it is used
ex. wind, solar, water

ecological footprint

the amount of land necessary to produce and maintain enough food and water, shelter, energy and waste for the population. the larger the footprint, the more negative the impact is on the ecosystem

pollution

any undesirable factor, or pollutant, that is added to the air, water, or soil; especially synthetic chemicals and materials added to the earth that cannot be integrated into normal ecosystem functions

greenhouse effect

occurs when carbon dioxide, water, and methane molecules trap energy in the Earth's atmosphere, which allows for a stable temperature so life can exist

greenhouse gases

CO2, H2O, CH4 - absorb heat energy in the atmosphere

indicator species/bioindicators

typically the first organisms in an ecosystem to be affected by pollution

biomagnification

-causes accumulation of toxins in an individuals' bodies in the food chain
-process in which pollutants move up the food chain as predators eat prey, accumulating in higher concentration in the bodies of predators, with the most serious effect in the bodies of the top predators

threats to biodiversity

-loss of habitat and pollution affect animal and plant populations
-loss of biodiversity can reduce an ecosystem's stability and make it more difficult for the ecosystem to handle future change
-biodiversity is highest in rainforests in the world, which are being deforested

habitat destruction

loss of habitat eliminates species

habitat fragmentation

when a barrier prevents an organism from accessing its entire home range

introduced species

any organism that was brought to an ecosystem as the result of human actions
-threaten the stability of ecosystems; are better competitors or are predators of native species
-cause tremendous damage to the environment
ex. fire ants, kudzu, zebra mussels, purple loosestrife, burmese pythons

conservation practices

-laws that protect endangered or threatened species also protect their habitat and other organisms around them
-control how fast our population grows by controlling birth rates
-develop technology to produce more food and produce less waste
-change our practices and take action to protect and maintain ecosystems
-reduce or eliminate the pressures we place on the planet's biogeochemical processes