Paper 2 - B10-B17

• Habitat


  The environment in which an organism lives
• Population


  Total number of organisms of the same species living in the same geographical area.
• Community


  The populations of all of the different species that live in the same habitat.
• Biotic factor


  A factor of an environment that is living
• Abiotic factor


  The non-living parts of an environment
• Ecosystem


  Biotic and antibiotic factors of an environment and how they interact.
• Living organisms compete with each other for resources.
• Plants compete with each other for light and space, water and mineral ions in the soil.
• Animals compete for food, water, mating partners and territory.
• Interdependence


  Species in a community depend on each other as every animal depends on living organisims for food.
• If a species disappears from a community then this can affect the whole community.
• Stable community


  The population of organisms are in balance with each other.
• Functional adaptations


  Adaptations to the body functions of an organism
• Behavioural adaptations


  Adaptations to the animal's lifestyle or behaviour.
• Dry conditions


  Adapted to reduce water loss and regulate body temperature
• Cold conditions


  Heat loss through insulation and less surface area.
• Extremophiles


  Organisms that are adapted to live in very extreme conditions.
• Depending on their conditions extremophiles can withstand high pressures, high temperatures and high concentrations of substances like salt.
• Tertiary consumer, Secondary consumer, Primary consumer, Producer
• Producers synthesise complex molecules - make glucose through photosynthesis.
• Producers are the source of all the biomass (molecules like glucose) in a community.
• Organisms that eat producers are primary consumers.
• Primary consumers are then eaten by the secondary consumer.
• A tertiary consumer eats the secondary consumer.
• Consumers that kill and eat other animals are called predators.
• The number of predators and prey rise and fall in cycles. This only happens in a stable community when all biotic and abiotic factors are in balance.
• Predator-prey cycles will change based on biotic and abiotic factors.
• Biotic factor, Availability of food:

  If the availability of food falls, then the number of organisms in that community will also fall.
• Biotic factor, Arrival of a new predator:

  Causes the population of a prey species to fall. Effects existing predators if they are competing for the same prey
• Biotic factor, Competition:

  If a species is outcompeted then its population can fall so much that numbers can't breed causing extinction.
• Biotic factor, New pathogens:

  If an infectious disease emerges and then spreads it can wipe out a population of a species
• Abiotic factor, Light intensity:

  If the light intensity is too low then the rate of photosynthesis falls and plants will grow more slowly. If plants grow more slowly, then animals which feed on plants may not have enough food.
• Abiotic factor, Temperature:

  If the temperature of an environment changes then this could cause the distribution of species to change.
• Abiotic factor, Water:

  Both animals and plants need water to survive
• Abiotic factor, pH and mineral content of the soil:

  Many plants cannot grow on soil which is too acidic or too alkaline. Plants need nitrate to make amino acids
• Abiotic factor, Wind intensity and direction:

  If an ecosystem is near the sea, water is blown off of the plant.
• Abiotic factor, Carbon dioxide and oxygen:

  If carbon dioxide levels fall then the rate of photosynthesis can decrease. The level of oxygen in the air stays fairly constant. The level of dissolved oxygen in water can fall.
• Structural adaptations


  Adaptations of body shape or body structure
• A transect is a line such as a tape measure or a piece of rope.
• A quadrat is then used to count the number of organisms at intervals on the transect