B7 specification

• Recall what an ecosystem is

  interaction of a community of living organisms with non-living parts of the environment
• describe which resources animals compete for

  • space
  • food
  • water
  • mates
• describe which resources plants compete for

  • light
  • space
  • water & mineral ions
• why do organisms compete?

  • to survive & reproduce
  • organisms compete with other species for the same resources
• Explain the term 'interdependence'

  • interdependence: each species depend on other species for food, pollination, seed dispersal, etc
• Explain the term 'stable community'

  • species & environment are balanced so population size is roughly constant
• Name some abiotic that affect communities

  1. moisture level
  2. light intensity
  3. temperature
  4. soil pH
  5. wind direction
• Name some biotic factors that affect communities

  1. new predators
  2. competition
  3. new pathogens
  4. availability of food
• explain how a change in an abiotic factor might affect a community

  • change in environment could can affect size of populations in community
• explain how a change in a biotic factor might affect a community

  • change could be a new biotic factor which also changes size of population which can have knock-on effects due to interdependence
• Describe structural adaptations of organisms

  • feature's of an organism's body structure- shape or colour
  • fat
  • white
• Describe behavioural adaptations of organisms

  • way they behave
  • migrating to warmer climates when cold
• Describe functional adaptations of organisms

  • inside an organism's body like reproduction or metabolism
  • desert animals sweat little
  • bear hibernate & lower metabolism
• Describe what an extremophile is

  • microorganisms that live in extreme conditions
• represent the feeding relationships within a community using a food chain & describe these relationships

  • food chains show what's eaten by what in an ecosystem
  • starts with producer: makes own food using energy from sun
  • they make glucose from photosynthesis & other molecules- these other molecules is known as BIOMASS- mass of living material
  • energy transferred when organisms eat
  • producers eaten by primary consumers
  • primary eaten by secondary consumers
  • secondary eaten by tertiary
• food chain!

  represents energy trasnsfers between organisms

  A) producer

  B) primary

  C) secondary

  D) tertiary

  
• Describe and interpret predator-prey cycles

  1. population of any species is usually limited by food availability
  2. if prey increase then so will predators
  3. if predator increase, prey will decrease
  4. out of phase with each other because it takes a while for one population to respond to changes in another
• Explain how and why ecologists use quadrats and transects

  • used to sample organisms in an area & investigate how distribution affected by environmental factors
  • measure how common an organism is in 2 sample areas using quadrats & compare
  • distribution change across an area by placing quadrats along a transact
• • quadrats compare
  • transects investigates distribution
• [Required practical 9]: measure the population size of a common species in a habitat. Use sampling to investigate the effect of one factor on distribution

  1. place a quadrat on ground at a random spot within the first sample area
  2. count all organisms in quadrat
  3. repeat step 1-2 as many times you can
  4. work out mean number of organisms per quadrat in 1st sample area
  5. repeat 1-4 for second sample area
  6. compare 2 means
• population size of organism in 1 area

  1. work out mean number of organism per m²
  2. then multiply mean by total area of habitat
• using transects

  1. mark out a line in area you want to study with tape measure
  2. collect data along line
  3. count organisms that touch the line OR use quadrats next to or at intervals
• estimating percentage cover of a quadrat

  1. count squared covered by organism
  2. divide number by total & get percentage
• Describe the processes involved in the water cycle

  1. energy from sun makes water EVAPORATE into vapour
  2. water evaporated from plants known as TRANSPIRATION
  3. vapour carried upwards where it coold & CONDENSES to form clouds
  4. water falls from cloud as precipitation

  • some water absorbed by soil taken by roots
  • water not absorbed RUNS OFF into streams
  • process repeats

  A) transpiration

  B) condensation

  C) precipitation

  D) evaporation

  
• describe the processes involved in the carbon cycle

  1. CO² taken during photosynthesis to make glucose
  2. when plant respire, some CO² returns
  3. plants eaten makes carbon move through food chain
  4. animals respire
  5. organisms die & microorganisms feed on their remains; when they respire, CO² returns
  6. combustion release CO²

  • carbon is constantly cycled- from air, food chains & back into air

  A) photosynthesis

  B) respiration

  C) death

  D) decay

  E) burning

  
• Describe what biodiversity is

  variety of different species of organisms on Earth or within an ecosystem
• describe why biodiversity is important

  to make sure that ecosystems are stable because of interdependence & maintaining physical environment
• describe how human activities affect biodiversity

  • waste production, deforestation & climate change reduce biodiversity
• describe the impact of human population growth & increased living standards on resource use

  • population is rising quickly due to modern medicine & farming which reduces death from disease & hunger
  • also means we're having a bigger effect on environment
  • increase population = pressure on environment to survive
  • to increase standard of living by using raw materials & energy quickly
  • demands are higher than materials can be replenished so it's likely to run out
• describe impact of human population on waste production

  1. Water: chemicals used on land can get washed into water, affecting plants & animals which rely on oceans for survival
  2. Land: toxic chemicals for farming
  3. air: smoke released into atmosphere can pollute air
• describe how pollution can occur

  from combustion of fossil fuels
• impacts of pollution

  • melting ice caps
  • rise in sea levels
  • reduce biodiversity
• global warming

  • carbon dioxide & methane trap energy from sun; heats up earth due to & increases greenhouse gas levels
  • gases serve as an insulating layer
• destroying peat bogs

  • bogs are acidic
  • carbon is stored in peat instead of released
  • bogs are often drained for farmland & use peat as fuel
  • some microorganisms decompose the dried peat which causes them to respire
  • peat burnt as fuel
  • reduced biodiversity
• Deforestation

  • cutting down trees for
  • room for farming
  • Grow crops to contribute to biofuel
• consequences of deforestation

  1. less carbon take in
  2. more carbon dioxide in atmosphere: microorganisms feed on dead trees, tree burnt
  3. less biodiversity: habitats destroyed
• programmed aimed to reduce effects of humans on ecosystems

  • breeding programmes
  • prevent endangered species from going extinct
  • animals bred in captivity & some are released into wild to boost population
• programmed to reduce negative effects of humans on ecosystems

  • people encouraged to recycle & reduce waste dumped in landfill
  • Governments introduce programmes to reduce deforestation & carbon dioxide released
  • regenerate rare habitats like heathlands & protect species living there
• • protecting biodiversity costs money
  • reduces people’s livelihood: reducing deforestation might reduce people’s jobs
  • conflict between biodiversity & food security