biology paper 2

• what is a community


  where all organisms coexist and live dependant on each other
• what are the cycles between prey and predators

  as prey increase so do predators.

  prey decrease so do predators which allow prey to increase
• what do animals compete over

  mates

  food

  habitat
• what do plants compete over

  soil space

  water

  mineral ions

  light intensity
• what is interdependence?

  different organisms depend on each other for things like food an habitats
• what happens without interdependence?

  populations may fluctuate due to prey and predator numbers
• abiotic

  non living factors
• biotic


  living factors
• examples of abiotic factors

  light

  temperature

  minerals
• examples of biotic factors

  food

  pathogens
• levels of organisation

  producer---- primary consumer---secondary--- tertiary---
• adaptations


  allow animals to survive better within there habitats
• what are adaptations for cold areas

  more fur

  normal sweat

  white fur
• what are adaptations for warm areas?

  less sweat

  thinner fur

  bigger ears

  hunt at night
• structural adaptations

  sharp teeth

  camouflage
• functional adaptations

  late embryo implantation

  less sweating
• behaviour adaptations

  play dead

  hunt at night

  bask in sun
• what is an extremeophile

  an organism that has adapted to live in an extreme climate
• where may extremeophiles live

  deep sea vents

  high pressure areas

  high salt concentration areas
• CARBON CYCLE- evaporation 


  water turns liquid into gas when it evaporates
• CARBON CYCLE- condensation

  evaporation water cools and converts from gas to liquid
• CARBON CYCLE- infiltration

  occurs when water has fallen as precipitation and is absorbed into the ground
• rate of decay

  speed of at which dead matter is broken down by decomposers
• rate of decay- high temperature

  decomposes = more active so rate increases
• rate of decay- low temp

  decomposers = less active so the rate decreases
• rate of decay- oxygen avalibility

  decomposers need oxygen for respiration to reproduce= more oxygen higher rate
• peat bogs

  low oxygen, low temp, acidic water

  natural mumification
• rate of decay

  decomposers need water to survive= more water rate increases
• farmers

  use manure and compost as fertilisers
• anaerobic decay

  fungi+bacteria break down matter without oxygen

  water logged areas
• products of anaerobic decay

  methane

  co2
• biogas generators

  anaerobic digestion
• trophic level

  the position of an organism within the food chain
• biomass

  the total mass of living things in a trophic level
• how much energy is transfered per biomass level

  10%
• why is only 10% transferred

  not all the organism is eaten

  energy is released as heat

  energy is being used within the organism
• food security


  enough food to meet the populations demands for food
• factors that affect food security

  increase in birthrate

  changing diets

  new pathogens

  flooding
• new pathogens

  intensive farming = closer together= more disease
• natural disaters

  lack of crops

  farmers increase prices= people cannot afford

  can cause famine