rest of b4

Cards (46)

  • what are the 3 parts of an ecosystem?
    producers - organisms that make their own food using photosynthesis
    • plants and algae
    consumers - organisms that cannot make their own food. they eat other organisms to gain energy.
    • animals
    decomposers - a special group of consumers. they gain their energy by feeding on dead/decaying material.
    • bacteria and fungi
  • how is energy transferred between organisms?
    energy from the sun is transferred by light to the chlorophyll in the cells of a producer.
    1. CO2 and H20 --> C6H1206
    • converted into carbohydrates, proteins and fats, which are used as energy stores, and for growth and repair.
    2. as an organism grows, it increases its biomass.
    3. consumer eats producers
    4. when the organism respires, the energy stored in its food is transferred in the production of ATP
    5. the organism grows and its biomass increases
  • what is a food chain?
    displays what an organism eats
  • what do the arrows in a food chain show?
    the transfer of biomass and therefore the transfer of energy from one organism to the next.
  • what is another word for each step in the food chain?
    a trophic level
  • what is a food web?
    a series of interlinked food chains
  • what is one drawback of food chains?
    only show organisms eating one food source which is not accurate as in most communities, animals eat more than one type of organism
  • what are biotic factors?
    the living factors
  • what are abiotic factors?
    the non-living/physical factors
  • what do biotic factors normally refer to?
    the interactions between living organisms
    e.g. many organisms compete for factors such as food, space and breeding partners.
  • what is the most common biotic factor?
    competition
  • give 4 examples of abiotic factors.
    light intensity, temperature, moisture levels and soil pH
  • how does light intensity affect communities?
    light is required for photosynthesis.
    • the greater the light available, the greater the success of a plant.
  • how does temperature affect communities?
    it has the greatest effect on the enzymes that control metabolic reactions.
    • plants develop more rapidly in warmer temperatures as their metabolisms will be faster.
  • how do moisture levels affect communities?
    for most plants and animals, a lack of water leads to death.
    • e.g. water is the main component of blood plasma
    a lack of water for plants causes plants to wilt
    • water is required to keep their cells turgid, which keeps plants upright
    water is also required for photosynthesis
  • how does soil pH affect communities?
    the pH of soil affects the availability of certain minerals.
    • some plant species grow better in acidic soils, like ferns.
    • others grow better in alkaline soils, like cucumbers
  • how can light intensity be measured?
    light meter
  • how can the moisture be measured?
    humidity sensor
  • how can pH be measured?
    a pH probe
  • what do plants need to survive?
    light, water, carbon dioxide, minerals and space
  • what do animals need to survive?
    food, water, breeding partners, territory and shelter
  • population
    the number of organisms of each species living in an area
  • does competition have a direct effect on the size of a population?
    if materials (e.g. food, water, space) are limited, weaker competitors may die or leave the area
    • decrease in population
    if there is a large amount of materials (like food), the population is likely to thrive and increase
  • interdependance?
    how different organisms depend on each other within a community
  • what is predation?
    the relationship between a predator and prey species.
    • the size of the predator population directly affects the size of the prey population and vice versa
  • mutualism

    in a mutualistic relationship, both organisms benefit from the relationship.
  • an example of a mutualistic relationship: oxpeckers and buffalo
    oxpeckers --> small birds that live on the buffalo
    • they eat the ticks and fleas on the buffalo
    • they gain food
    buffalo --> free from irritation and potential disease
  • parasitism
    only one organism (the parasite) gains.
    the organism it lives off (the host) suffers
  • example of a parasitic relationship
    tapeworms in an animal's digestive system
    fleas
  • food chains show the flow of biomass through a community.
    however, they dont show the number of organisms involved, or the size of biomass transferred.
  • what do pyramids of numbers show?
    the population at each trophic level
    • the bar width represents the number of organisms present
  • how do scientists calculate biomass?
    1. take samples of organisms from each trophic level
    2. measure the average mass of these organisms
    3. multiple the mass by the number of organisms present to calculate the total biomass at each trophic level
  • what kind of mass to scientists usually calculate?
    dry mass, because water content can vary between individuals.
    • organisms are killed and dried in a kiln
  • why does biomass decrease at each trophic level?
    biomass is lost when:
    • not all of an organism is eaten e.g. animal bones
    • some is used in respiration
    • some parts of an organism cannot be digested e.g. hair and teeth.
    • waste products are lost through excretion e.g. urea is lost in urine
    furthermore, not all of the organisms at the previous trophic level are eaten.
    • their biomass is not transferred
  • efficiency of biomass transfer (%)
    biomass available after transfer (g or kg) / biomass available before transfer (g or kg) x 100
  • a lamb gains 12kg in mass after consuming 150kg of grass. calculate the efficiency of biomass transfer.
    12 / 150 x 100 = 8%
  • what are decomposers?
    they are microorganisms like bacteria and fungi.
    • they break down/decay dead organic material
    • they also break down animal waste, like faeces and urine
  • how do organisms like saprophytes get their food?
    they feed on dead material, as through decomposition, nutrients are released.
  • what are detritovores?
    they are small animals.
    • they speed up decomposition by shredding organic material into very small pieces
    • this creates a larger surface area for decomposers to work on
  • give 3 examples of detritivores
    earthworms, woodlouse and maggots