ecology + use of biological resources

habitat definition

place where organisms live

population definition

all organisms of one species in a habitat

community definition

all different species in a habitat

ecosystem definition

all of living organisms in an area and abiotic conditions

examples of biotic factors

food availability

predators

infection from pathogens

competition

examples of abiotic factors

sunlight

temperature

pH

water

soil type

salinity

why do quadrats need to be placed randomly

to avoid bias and to make sure the experiment is carried out fairly

biodiversity definition

the measure of variety of different species in an ecosystem

advantages of high biodiversity

ecosystems are more stable and able to sustain changes in environment

how has biodiversity been reduced by human factors

pollution

deforestation

global warming

producers definition

suppliers of energy for the ecosystem

usually plants which photosynthesis

consumers definition

animals that eat the plants or other animals

decomposers definition

bacteria or fungi which decay dead material in order to recycle nutrients

physical environment definition

includes all non-biological components

biomass definition

total amount of living material in an organism

what does a pyramid of energy transfer show

how much percentage of energy is passed on between trophic levels

how is energy transferred along a food chain

plants use energy for food via photosynthesis

around 90% of energy is lost in various ways

some parts of food are inedible too, so energy isnt taken in too

alot of the energy that is taken in is used for staying alive (e.g. in respiration)

only around 10% of the total energy available becomes biomass (e.g. stored or used for growth )

carbon cycle

carbon can be:

released during respiration

taken in during photosynthesis

passed from plants to animals when herbivores feed, passed between animals when carnivores feed

released during decomposition

released during combustion of fossil fuels

nitrogen cycle process

nitrogen fixation

transfer of nitrogen between organisms

nitrification

denitrification

nitrogen fixation

converts nitrogen gas into ammonium ; which is also converted into nitrates in the soil

can also be fixed by lightning, or during production of chemical fertilizers

carried out by nitrogen-fixing bacteria

after nitrogen fixation, plants absorbs nitrates in the soil and uses the nitrogen to build plant proteins

transfer of nitrogen between organisms

animals feed on plants and digest the proteins in plant tissues

nitrogen may be passed then from one consumer to another up the food chain in the same way

nitrification

conversion of ammonium compounds to nitrates

nitrogen from living organisms is returned to the soil in the form of ammonia by decomposers

plants cant absorb ammonia so nitrifying bacteria convert it to nitrates which can then be taken up by plants

denitrification

nitrates in the soil can be converted back into nitrogen gas by the denitrifying bacteria

denitrifying bacteria are active in anaerobic conditions

gases of air pollution

carbon monoxide

sulfur dioxide

how is carbon monoxide formed

combustion is carried out without sufficient oxygen supply

mainly released in car emissions

effects of carbon monoxide

it is a poisonous gas

combines with haemoglobin in blood instead of oxygen

how can emission of carbon monoxide by decreased

modern cars are fit with catalytic converters that turn carbon monoxide into carbon dioxide

decreasing amount of CO released in the atmosphere

how is acid rain formed

sulfur dioxide is formed from sulfur impurities in fossil fuels

when gas is mixed with rain cloud to form dilute sulfurous acid

falls as acid rain

causes of acid rain

internal combustion engines in cars

power stations

effects of acid rain on the environment

causes lakes to become more acidic

most organisms are sensitive to changes in pH and cant survive in acidic conditions

acid rain kills trees by damaging leaves and releasing toxic substances from the soil, making it hard for the trees to take up nutrients

examples of greenhouse gases

carbon dioxide

methane

nitrous oxide

CFC

eutrophication

when excess nitrates and phosphates are put onto fields and it rains afterwards, they are washed through the soil and into rivers and lakes

they first add extra nutrients

causing algae to grow fast and block out the light

plants cant photosynthesis due to lack of light and starts to die

microorganisms feed on dead plants and increase in number, they deplete the oxygen in the water too

organisms that need oxygen die

disturbing evapotranspiration

evapotranspiration includes both the process of water evaporating from the earth’s surface and plant from transpiration

water falls back on the earth as rain

when trees are cut down, evapotranspiration is reduced, which makes the local climate drier

soil erosion

tree roots hold the soil together

when trees are removed, soil can be washes away by the rain (eroded)

leaving infertile ground

leaching

trees take up nutrients from the soil before they can be washed away by rain

but return them to the soil when leaves die

when trees are removed nutrients get leached away but dont get replaced

leaving infertile soil

how does sewage effect the environment

growth of bacteria

reduce availability of oxygen in water

organic fertilizer

manure mixed with straw

not bad for environment

not efficient = no control over content of minerals

inorganic fertilizer

carefully formulated chemicals from potassium, phosphorus, nitrate and ammonia

bad for environment = likely to lead to eutrophication

bought in bulk, spread evenly on crop

pests definition

any organism that reduces yield of a farmers crop / livestock

advantages of pesticides

kills all pests

cheap

easy to apply

fast-acting

disadvantages of pesticides

can evolve resistance

needs to be reapplied regularly

can poison other organisms when getting into food chains

advantages of biological control

doesnt involve chemicals

only need to apply once

specific to killing the pest

disadvantages of biological control

doesnt wipe out pest, only controls it

can be slow

may also affect other organisms in the food web

bacteria used to make yoghurt

lactobacillus

fermentation definition

microorganisms break down nutrients to release energy

through anaerobic respiration

steps to make yoghurt

sterilization

pasteurization

incubation

fermentation

add flavours

sterilization

clean equipment to kill unwanted microorganisms

pasteurization

milk is heated to around 75°C to further kill unwanted microorganisms

milk is then cooled

incubation

lactobacillus bacteria is added

left in a fermenter to reproduce and multiply

fermentation

bacteria ferment the lactose sugar in milk to form lactic acid

what does lactic acid do to milk

clots and solidify milk and makes yoghurt tangy

fermenters

grows microorganisms in industry

can hold up to 250 000 dm³ of liquid culture

culture medium

where microorganisms can grow and reproduce

how fermenters are used

sterilization

microorganisms are added

motor moving

water moving

pumping air

adding probes

how to sterilize fermenters

pumping steam at high pressures

stops contamination

equipment is now aseptic

what do motors do in fermenters

turns stirring paddles

helps keep solution agitated

why are probes added in a fermenter

to measure temperature and pH

why is air pumped into a fermenter

for the microorganisms to respire aerobically

when and why would the water jacket have cool water running through it

cools the fermenter

prevents overheating

keeps temperature steady

why is increasing crop yields important

dealing with climate change

feeding more people

protecting the environment

how can crop yields be increased

maximize photosynthesis

fertilizers

controlling pests

how to maximize photosynthesis to increase crop yields

in greenhouses and polytunnels

conditions can be controlled

features of greenhouses

transparent materials - allows lot of light for photosynthesis

additional lighting in winter

additional heaters

carbon dioxide is released

water supply is controlled

humidity level is controlled

how is carbon dioxide released in greenhouses

as a byproduct of combustion of fuel to be used by plants

why is high humidity bad in greenhouses

high levels of humidity can breed fungi and bacteria

why are additional heaters added in greenhouses

to ensure temperature is optimum for enzymes

how does dough rise during breadmaking

yeast carries out anaerobic respiration and forms bubbles of carbon dioxide in the dough

steps for making bread

make dough

enzymes activate

yeast switches to anaerobic respiration

dough is kneaded

left to rise

bake

what ingredients are used to make bread

yeast

flour

water

sugar

what do enzymes release when they activate in yeast

sugars

what is sugar used for when released by yeast

aerobic respiration

until yeast runs out of oxygen

what does yeast produce in anaerobic respiration

carbon dioxide

ethanol

what happens when dough is left to rise

carbon dioxide bubbles get trapped and expands

what happens when bread is baking

yeast is killed

ethanol gets evaporated

what is needed when investigating rate of anaerobic respiration by yeast

paraffin oil

glucose

limewater

what is paraffin oil used for when investigating rate of anaerobic respiration by yeast

prevents oxygen from getting to yeast

what is limewater used for when investigating rate of anaerobic respiration by yeast

to detect carbon dioxide

anaerobic respiration = glucose + oxygen —>

ethanol + carbon dioxide

interspecific definition

between different species

intraspecific definition

within same species

interspecific protection from predators

using nets to prevent predation from other animals

intraspecific protection from predators

seperating fish by age and size

to stop older/larger fish from eating the more weaker ones

protection from pests and disease in fish farming

dead fish are removed quickly

antibiotics are added

pesticides

biological controls

optimizing fish diets

high protein diet

food pellet made from smaller fish

contain additives like antibiotics

what happens when food pellets are made from smaller fish

decrease in wild fish species

growing fish in tanks

water can be filtered to remove waste

sensors monitoring

what do sensors monitor in fish tanks

pH

oxygen

temperature

optimizing fish breeding

selective breeding from healthy, large fish that dont need too much food

selective breeding definition

breeding two organisms that have desirable characteristics

why does selective breeding take place

increases chances of offspring inheriting good characteristics

why are animals selectively bred

higher yield

produce greater quantity of offspring

ability to run faster

more resistant to disease and pests

process of selective breeding

animals with desired characteristics are chosen

bred together

offspring showing desired characteristics are selected

they are bred together

carried out over many generations

recombinant dna definition

gene that is cut out of one species and inserted into another

transgenic organism definition

organism that recieves the recombinant dna

restriction enzymes definition

cut dna molecules at specific points

dna ligases definition

join ends of dna molecules

vector definition

used to transfer dna into a cell

two main vectors

plasmids

viruses

why are plasmids good for using as vectors

found inside bacteria

easily removed, edited and then used to insert recombinant dna

why are some viruses good for using as vectors

they naturally will insert dna into the organisms they infect