Ecosystems

• What is an ecosystem

  A biological community of interacting organisms and their physical environment.
• What are the two different components of an ecosystem

  Abiotic and biotic
• What is a biotic component


  A living feature of an ecosystem

  e.g. plants, fish
• What is an abiotic component

  A non-living feature of an ecosystem.

  e.g. climate, soil, sunlight
• What are the different sized ecosystems

  -local small scale ecosystems such as pond, woodland

  -global scale ecosystems such as tropical rainforest, desert which are also called a biome
• What is a producer

  an organism that converts energy from the environment (mainly sunlight) into sugars (glucose) - most obviously plants which convert energy from the sun by photosynthesis
• What is a consumer


  An organism that obtains energy by feeding on other organisms
• What is a decomposer


  An organism that breaks down other living things to obtain nutrients/energy.

  e.g. bacteria and fungi
• What is a food chain


  A series of steps in which organisms transfer energy by eating and being eaten
• What is a food web

  a system of interlocking and interdependent food chains.
• What is the nutrient cycle

  Food that are used by plants or animals to grow. There are two main sources:

  -rainwater washes chemicals out of the atmosphere

  -weathered rock releases nutrients into the soil

  When plants or animals die, they help to recycle the nutrients making them available once again for the growth of plants or animals
• What does a freshwater pond ecosystem provide

  provide a variety of habitats for plants and animals because there are big variations in the amount of light, water and oxygen available

  -at the bottom of the pond=small animals such as water flea, water worm

  -at the outside of the pond=frog marsh, marigold, dragonfly

  -plants like reeds grow around the edge of the pond
• Species you find in a freshwater pond ecosystem

  frog tadpole- get energy from microscopic plants, algae

  algae- get energy from sunlight

  sticklebacks- get food from tadpoles, water fleas

  heron- get food from fish, frogs, tadpoles

  perch- get food from small fish
• What makes an ecosystem sustainable

  For an ecosystem to be sustainable it must be balanced, so all parts of an ecosystem play an important role in the stability of the ecosystem
• Give global ecosystems


  tundra

  tropical grassland

  Mediterranean

  Temperate grassland

  Deciduous and coniferous forests

  Polar

  Desert

  Tropical rainforest
• What are the characteristics of a tundra ecosystem

  Characterised by low-growing plants adapted to retain heat and moisture in the cold, windy and dry conditions. A fragile ecosystem, easily damaged by humans and threatened by developments such as oil exploration and tourism . Animals, e.g. reindeer are adapted to survive the cold
• Where are tundra environments located

  From the arctic circle to about 60-70 degrees north. There are only very small areas in the southern hemisphere due to the lack of land at these latitudes
• What are the characteristics of a tropical grassland ecosystem

  Characterised by distinct wet and dry seasons with wild fires and violent thunderstorms. Large herds of animals graze these areas, along with predators such as lions and leopards
• Where are tropical grassland ecosystems located

  between 15-30 degree north and south of the equator
• What are the characteristics of a Mediterranean ecosytem

  These areas enjoy hot, sunny and dry summers, with mild winters. Vegetation includes olive trees and fruit trees, such as lemons and oranges. Other parts of the world, such as USA and South Africa, have similar climates
• Where are Mediterranean ecosystems located

  Roughly 40-45 degrees north of the equator. Also isolated locations south of the Equator (South Africa, Western Australia)
• What are the characteristics of temperate grassland ecosystems

  Includes the prairie of North America and steppes of Eastern Europe. Experiences warm, dry summers and cold winters. Grass species can tolerate these conditions and the land is mainly used for grazing animals
• Where are temperate grassland ecosystems located

  Roughly 30-40 degrees north and south of the Equator. Inland away from coast, with hot summers and cold winters
• What are the characteristics of deciduous and coniferous forests

  Deciduous trees shed their leaves in winter to retain moisture. Coniferous trees are evergreen, retaining their leaves to maximise photosynthesis during the brief summer months . UK's natural vegetation is deciduous. Further north. e.g. Canada, coniferous forests dominate
• Where are deciduous and coniferous forest located

  Roughly 50-60 degrees north of the equator
• What are the characteristics of a polar ecosystem

  Cold air sinks, resulting in very low temperatures and dry conditions. The main regions are Antartica and Greenland where temperatures can can fall below -50 degrees C
• Where are polar ecosystems located

  Arctic and Antarctic
• What are the characteristics of a desert ecosystem

  Covers one fifth of the world's land surface. Associated with sub-tropical high pressure belts-sinking air stops clouds forming, giving high daytime temperatures, cold temperatures at night and low rainfall. Plants and animals are well adapted to cope with dry conditions
• Where are desert ecosystems located

  Roughly 30 degree north and south of the Equator
• What are the characteristics of tropical rainforest ecosystems

  High temperatures and heavy rainfall at the equatorial low pressure belt make perfect growing conditions. Cover 6% of the Earth's land surface. More than half of the world's species of plants and animals live in this biome and a quarter of all medicines come from these plants
• Where are tropical rainforest ecosystems located

  Close to the Equator
• What are the variations in west-to-east belts of vegetation due to

  -winds

  -ocean currents

  -distribution of land and sea
• What does global atmospheric circulation determine

  It determines the variation in the type of vegetation in a region since it causes different climates
• Where are tropical rainforests found?


  Found in a broad belt along the equator and through the tropics in:

  -Central and south America

  -Central Africa

  -South east Africa

  -Northern Australia
• Why are tropical rainforests positioned where they are?


  They are positioned where they are because of the global atmospheric circulation.
• What is global atmospheric circulation?


  The movement of air around the planet which causes there to be high pressure at the tropics leading to the area being hot and dry. Surface winds also move heat from here to the equator. This creates an area of low pressure which leads to clouds forming and therefore rainfall. This results in the equator being warm and wet which creates the optimum environment for tropical rainforests
• What is the climate like in tropical rainforests?


  -Temperatures are high and constant throughout the year. This is because the sun is overhead most of the time

  -Rainfall is high because the global atmospheric circulation causes an area of low pressure to form at the equator

  -Rainfall varies throughout the year with a distinct wet season lasting around 6months. This is because of a period of intense rainfall when the equatorial low pressure area is directly overhead
• What is the soil like in a tropical rainforest?


  The soil isn't very fertile as heavy rain washes nutrients away (this is called leaching). There are surface nutrients due to decayed leaf fall, but this layer is very thin as decay is fast in the warm, moist conditions.

  -Many trees and plants have been adapted to have shallow roots to absorb these nutrients
• How have plants adapted to rainforests?

  -Most plants and animals are found in the canopy where there is lots of light

  -Many leaves have a 'drip tip' allowing heavy rain to run off the leaf without damaging the leaf

  - Trees are fast growing to out-compete other trees to reach sunlight

  -Epiphytes live on the branches high in the canopy to seek sunlight- the obtain nutrients from water and air not soil

  -trees have a wide base to support the tree since the roots aren't deep in the ground

  -shallow roots (buttress roots) since all the nutrients are found on the surface of the forest floor
• What kind of animals are found in tropical rainforests?


  -tropical rainforests support the largest member of species of any biome

  -Over 50% of all plants an animals species on earth live on 7% of the land surface

  -Birds live on the canopy feeding on nectar from flowers

  -Mammals like monkeys and sloths are well adapted to living in trees

  -Animals like deers and rodents live on the forest floor