B4

Ecosystems

species

group of individuals able to produce fertile offspring

ecosystem

how living & non-living organisms interact with e/o in a habitat

community

all the living organisms in an area

population

the # of organisms within the same species living in a habitat

biomass

the total mass of organisms in a given area

abiotic factors definition

non-living chemicals & physical factors influencing the living components of an ecosystem

3 main abiotic factors

• soil

• physical aspect

• climactic factors

soil

• pH determines type of plants

• diff water capacity/air content

• humus(dead organic matter) influences nutrients

climactic factors + effects (4)

• light(germination, growth, photosynthesis)

• temperature(enzymes, hibernation)

• wind (water loss, pollination)

• water

biotic factors

how living components interact with each other in an ecosystem

producers

the only living things using inorganic(non-carbon based) substances to make carbs

competition

the organism best adapted to compete for resources they need will win competition & survive

intraspecific competition

between individuals of the same species

• i.e. mates

interspecific competition

between individuals of different species

• i.e. prey, light intensity, water

mutualism

mutually beneficial interspecies co-operation

symbiosis

if both species cannot survive w/o e/o when mutualism is unavailable

parasitism

interspecies where host doesn’t benefit

predator-prey relationship graph

here, prey # higher than predator #, leading to higher peaks

prey-predator relationship simplified

• prey # increase, predator # increase(from food source » mating » offspring)

• more comp from hunting, predator # decrease

• prey # increases again

carbon cycle

the movement of carbon from living things into earth’s atmosphere & back

importance of carbon

• main component of all living cells

• can form polymers(bases of fats, carbs & nucleic acids)

• fuel component

carbon cycle diagram

CO₂ atmospheric » photosynthesis

6CO2 + 6H2O » C6H12O6 + 6O2

producers(photosynthesis) » animals

consumption » eat » digest » monomers synthesize their own molecules

• aerobic respiration (releases CO2)

• poo and death

• » decomposers

producers(photosynthesis)

• aerobic respiration (releases CO2)

• death

• » decomposers

decomposers

break down of dead materials by bacteria & fungi » releases CO2

fossilization

dead material not broken down from fossils becoming fossil fuels

• combustion, burned to release CO2

the water cycle

the continuous movement of water on, above & below the surface of the earth

• 1 reservoir to another (river to ocean)

• requires exchange of heat(solid, liquid, gas)

importance of water

• maintains habitats & transports nutrients

• all organisms take in water

precipitation

condensed water falling to the earth’s surface

evapotranspiration

total of all evaporation + transpiration

advection

movement of water in any state through the atmosphere

percolation

water flows horizontally through soil & rocks due to gravity

runoff

variety of ways water moves across the land

• can evaporate/infiltrate ground otw

human activities influencing water cycle

• agriculture

• urbanization

• deforestation

decomposers

break down dead organic material by releasing extra-cellular enzymes

• broken down into soluble material

detritivores

small animals that speed up decomposition into small pieces to increase SA (thus site of reaction)

3 factors affecting rate of decay

• temp

• O₂

• water

temperature’s effect on RoDecay

• high temp denatures enzymes & proteins

• low temp slows enzyme RoR preventing growth & reproduction

O₂ effect on RoDecay

• oxygen needed for aerobic respiration, lack thereof = no decay

water effect on RoDecay

• water for transport of nutrients

• helps digestion inside organisms

• no water = slow

rate of decay

proportion of a material that decays in a given period of time

• use comparatives!

rate of decay equation

(g/day) = change in mass(g) / time(days)

• large # = high RoDecay

nitrogen fixing definition + 3 diff types

nitrogen » nitrates

• in the soil

• legumes

• lighting- in the air

nitrogen fixing(in the soil)

nitrogen fixing bacteria in the soil converts nitrogen to nitrates in the soil, which is taken up by the roots of a plant

nitrogen fixing(legumes)

root nodules containing rhizobium(bacteria) converts nitrogen into nitrates directly

• the bacteria uses sugar from the roots, mutualism

nitrification

ammonia » nitrites » nitrates

• ammonia = poo & death, by nitrifying bacteria

• NH₄⁺ » NO₂^- » NO₃^-

denitrification

nitrates converted into nitrogen gas via denitrifying bacteria

• NO₃^- » N₂

nitrogen cycle diagram

trophic levels

feeding levels in a food web

• same level = same nutritional relationship to primary source of energy

• always starts /w producers

limitations of the foodchain

doesn’t show biomass & # of organisms

• arrows = energy direction

limitations of pyramid of numbers

# of organisms not always equal to biomass

pyramid of biomass drawing rules + example

1. produces always on bottom

2. always symmetrical(height is same for all, width = value)

3. draw the scale & adapt scale to values

4. MUST LABEL

energy transfer

energy transferred between trophic levels when an organism is eaten

• not all energy transferred = biomass decrease overall

how energy is lost between trophic levels

• not all parts eaten

• heat to surroundings

• movement

• growth & repair

• death » detrivores

calculations of efficiency

• trophic levels are limited as energy can’t sustain another population (more energy hunting than received)

• only 1% of energy from the sun is transferred into biomass

• 10% between trophic levels