Ecosystems

• all living things are found in places where they can cope with the local conditions, like temperature and the availability of food
• an ecosystem is all the organisms living in a community plus all the non-living (abiotic) conditions in the area in which they live
• ecosystems contain both biotic and abiotic condition:

  • biotic conditions are the living features of an ecosystem e.g. the presence of predators or food
  • abiotic conditions are the non-living features of an ecosystem, such as the temperature and soil
• in a freshwater ecosystem such as a lake, the biotic conditions would include the fish and the abiotic conditions would include the temperature of the water
• ecosystems very in size - can be small e.g. a pond or large e.g. an entire ocean
• the place where an organism lives within an ecosystem is known as its habitat e.g. an area of reeds at the edge of a pond
• within a habitat each species has its own niche
• a niche is the role of a species within its habitat, what it eats and where and when it feeds
• the niche a species occupies includes:

  • its biotic interactions - e.g. the organism it eats and those it is eaten by
  • its abiotic interactions - e.g. the temperature range an organism can live in, the time of day when an organism is active
• every species has its own unique niche - a niche can only be occupied by one species

  it may look like 2 species are filling the same niche (e.g. they are both eaten by the same species), but there will be slight differences (e.g. variations in what they eat)
• e.g. Common pipistrelle bat

  • lives throughout britain on farmland, open woodland, hedgerows and urban areas
  • it feeds by flying and catching insects using echolocation (high-pitched sounds) at a frequency of around 45 kHz
• e.g. soprano pipistrelle bat:

  • this bat lives in britain in woodland areas, close to lakes or rivers
  • it feeds by flying and catching insects using echolocation at a frequency of 55 kHz
  • may look like both species are filling the same niche (e.g. both eat insects) but there are slight differences (e.g. use different frequencies for their echolocation)
• if 2 species try to occupy the same niche, they will compete with each other

  one species will be more successful than the other, until only one species if left
• Adaptations:

  an adaptation is a feature that members of a species have that increase their chance of survival and reproduction

  • can be physiological (processes inside the body)
  • behavioural ( the way an organism acts)
  • anatomical (structural features of their body)
• e.g. giraffes have long necks to help them reach vegetation that's high up

  increases chance of survival when food is scarce
• • organisms with better adaptations are more likely to survive reproduce and pass on the advantageous alleles that determine these adaptations
  • this increases the frequency of these alleles in the population
  • means the adaptations become more common
  • natural selection
• metabolism is all the chemical reactions taking place inside an organism
• • every species is adapted to use an ecosystem in a way that no other species can - own unique niche
  • e.g. only giant anteaters can break into ants nests and reach the ants
  • they have claws to rip open the nest and a long sticky tongue which can move rapidly in an out of its mouth to pick up ants
• • organisms are adapted to both the abiotic conditions (e.g. how much water is available) and the biotic conditions (e.g. what predators there are) in their ecosystem
• adaptations to abiotic conditions:

  • otters have webbed paws - means they can both walk on land and swim effectively - increases their chance of survival bc they can live and hunt on both land and water
  • seals have a thick layer of blubber (fat) - helps to keep them warm in the coldest seas - increases their chance of survival bc they can live in places where food is plentiful
  • hedgehogs hibernate - they lower their rate of metabolism over winter - increases their chance of survival bc they can conserve energy during the coldest months
• adaptations to biotic conditions:

  • chimpanzees use twigs to fish termites out of termite mounds - increases chance of survival - gives them access to another source of food
  • male frogs produce mating calls to attract females - makes sure they attract a mate of the same species - increases chance of reproduction by making successful mating more likely
  • some bacteria produce antibiotics - these kill other species of bacteria in same area - increases chance of survival - less competition for resources