ecosystems and biodiversity

• what is a habitat?

  • place where an organism lives
• what is a population?

  • all the organisms of one species in a habitat
• what is a community?

  • all the different species in a habitat
• what is an ecosystem?

  • all the organisms living in a particular area and all abiotic conditions
• what is biodiversity?

  • the variety of different species of organisms on earth or within an ecosystem
• why is high biodiversity important?

  • make sure ecosystems are stable - different species rely on each other for things such as shelter or food
  • different species can also help to maintain right physical environment for each other
• what reduces biodiversity?

  • deforestation, pollution and global warming
• what biotic factors affect communities?

  • availability of food - more likely for survival of organism and to reproduce
  • Number of predators - if predators decrease then prey numbers increase and vice versa
  • competition - organisms compete with other species for same resources - plants = light, space, water, mineral from soil - animals = territory, shelter, food, water and mates
• what abiotic factors affect communities?

  • environmental conditions - distribution of species depends on average temperature, light intensity, moisture level and soil pH
  • toxic chemicals - pesticides and chemical fertilisers - pesticides can build up in food chains through bioaccumulation (each stage of food chain - concentration of pesticides increase - organism at top of chain receive a toxic dose) - excess fertilisers released into lakes and ponds cause eutrophication - leads to death of organisms).