ecosystems and ecology

what is a biotic factor

living factor

what is an abiotic factor

a non living factor

give 4 examples of a biotic factor

fungi plants animals bacteria

what are 4 examples of an abiotic factor

air, light, water, temperature

what is ecology

the study of the interactions among and between orgamisms and their abiotic environment

what is a biosphere

the part of earth that contains all ecosystems

what is a biome

a large region with same plant life and climate

what is an ecosystem

A community and its nonliving surroundings

what is a community

A population that lives together in a defined area

what is a population

A group of organisms of one type that live in the same area

what is an organism

An individual living thing

what is a species

a group of organisms that interbreed and produce fertile offspring

what does a classification key do

it’s used to identify an unknown organism typically uses a series of linked questions highlighting contrasting characteristics

what is the fundamental niche

it describes the full range of conditions and resources in which a species could survive and reproduce

what is the realised niche

It describes the actual conditions and resources which a species exist due to biotic interactions

what is resource partitioning

its where species alter their use of niche to avoid competition by dividing resources among them

why do ecologists investigate ecosystems?

to know what species exist and where they are located

what is sustainability

the use and manage of resources that allows full natural replacement of the resources exploited and full recovery of the ecosystem affected by their extaction and use

why are EIA’s (environmental impact assessment) conducted

to decide whether a project should go ahead or not

what 8 factors impact a population size

disease, climate, predation, food, temperature, sunlight, reproduction, rainfall

what are limiting factors

factors that restrict the populations continued growth

what are plants limiting factors

light, nutrients, water, carbon dioxide, temperature

what are the limiting factors of animals

space, foods, water, mates.

, predation, disease

what is a carrying capacity

where a population has an upper limit to the numbers that can be sustained in a given environment

what are examples of adverse conditions

too hot/cold, arid, not enough sunlight, poor soils

what is the benefit of safety in numbers

less chance of any individual being eaten

what is the benefit of predator co-operation hunting

there are more chance of a successful kill

what are the 2 limitations to population growth

density independent or density dependant

what are examples of density independent

climate, soil, fertility, amount of sunlight

what are examples of density dependent

competition for food, territory, finding a mate, disease

what is carrying capacity

the maximun number of a species or ‘load’ that can be sustainably supported by a given area/habitat/environment

when does exponential growth occur

when limiting factors are not restricting the growth of the population

what are decomposers

organisms which break down dead plants and animals and their waste

what do trophic levels show

they show where organisms are in the food chain

what is dynamic equilibrium

when the system is in a steady state which is achieved by self regulation

what is positive feedback

when the original change creates even more change which upsets the balance of a steady state and creates a chain reaction which causes a disproportionately large response

what is negative feedback

when certain parts of the system change when other parts change so that it remains the same

what is an example of positive feedback

climate change

what is the first law of thermodynamics

energy cannot be created or destroyed

what is the second law of thermodynamics

when energy is transferred some energy must be degraded down into a less useful form, energy transfer is not very efficient

what does a pyramid of numbers show

the total number of individual organisms at each level in the food chain of an ecosystem

what does an ecological pyramid show

the number of organisms in each trophic level

the mass of all organisms in each layer(biomass)

the amount of energy in each layer(productivity)

what does a pyramid of biomass show

the total amount of biomass in each trophic level also known as the standing stock which is affected by seasonal variations

what do pyramids of energy/productivity show

the flow of energy in an ecosystem

why do we use pyramids of biomass and not pyramids of numbers

beacuse it overcomes the problem of an inverted pyramid of number

whats an advantage of a pyramid of number

simple and easy way to compare changes in population numbers with time of season

whats are 3 disadvantages of pyramids of numbers

can be inverted

numbers can be too great to represent accurately

does not allow for immature forms

what is the advantage of a pyramid of biomass

it overcomes the inverted triangle problem in a pyramis of numbers

what are 2 disadvantges of a pyramid of biomss

only uses a sample of the population so does not measure biomass accurately

orgnanisms must be killed to measure dry mass

what are 3 advantages of a pyramid of energy

allows for rate of production over time

allows comparison of different ecosystems

never inverted pyramids of energy

what are 2 disadvantages of a pyramid of energy

issues of where to place decomposers

issues of consumers at more than one trophic level

time consuming to measure growth and reproduction over time

what is gross primary productivity (1)

the conversion of energy into biomass for a given period of time measured as productivity

what is gross primary productivity in plants

photosythesis

what is net primary prowhat is net prductivity

the rate at which plants accumulate dry mass(actual plant growth)

what is net primary productivity measured in

unit area per unit time

how do you calculate net primary productivity

NNP=GPP-R

what does the net primary productivity calculation show

the gain by producers in energy or biomass per unit area per unit time after allowing for respiration losses

what is gross secondary productivity

a measure of all the food an animal eats

what is net secondary productivity

the total gain in biomass per unit area per unit time by consumers after allowing for losses to respiration

what is energy assimilation

absorption/digestion

what is bioaccumulation

the process by which toxins build up in individual organisms over time

what is biomagnification

the process by which toxins are passed from one trophic level to the next(increase in concentration) within a food web

what are the organic stores of carbon

organisms(biomass)

what are 4 inorganic stores of carbon

atmosphere

soil

fossil fuels

oceans

what is zonation

where communities change over a distance.

what is succession

when communities change over time

what is a sere

the change from the earliest community to the final community

what do disturbances do

creates gaps that can be colonised by piorneer species within the surrounding community