B4.1.1 ecosystems

• ponds are a good way of attracting animals into the garden. a pond is an example of an aquatic ecosystem
• in the pond:

  ecosystem: frogs, fish, insects, plants algae, light intensity, temperature, moisture levels and soil pH

  habitat: pond including the water, stones and soil

  community : frogs, fish, insects, plants and algae

  population: number of frogs
• how are ecosystems organised?

  an ecosystem is made up of:

  1. all living organisms
  2. physical conditions in the area
• how are ecosystems organised?

  the community is:

  all organisms of different species
• how are ecosystems organised?

  the habitat is: the area which an organism lives
• how are ecosystems organised?

  the population is:

  total number of organisms of one of the species in the area
• you can divide the organisms in a community into 3 groups

  1 . PRODUCERS

  organisms that make their own food by PHOTOSINTHESIS by absorbing LIGHT energy and converting it into CHEMICAL energy (glucose) which they make available to the rest of the food chain when ANIMALS eat them. this is why producers START food chains. they include all plants and algae
• you can divide the organisms in a community into 3 groups

  2 . CONSUMERS

  organisms that CANNOT make their own food. they have to EAT other organisms to gain ENERGY. all ANIMALS are consumers
• you can divide the organisms in a community into 3 groups

  3 . DECOMPOSERS

  special group of consumers. they gain their energy by feeding on DEAD and DECAYING material. they are important for RECYCLING nutrients so they do not run out
• how is energy transferred between organisms?

  energy from the SUN is transferred by LIGHT to the CHLOROPHYLL in the cells of the CHLOROPLASTS, here carbon dioxide and water react to produce glucose, which stores energy within its chemical bonds.
• how is energy transferred between organisms?

  glucose can be converted into carbohydrates, fats and proteins which are used as ENERGY STORES and for GROWTH and REPAIR.
• how is energy transferred between organisms?

  as an organism grows it increases its BIOMASS
• BIOMASS IS THE MASS OF LIVING MATERIAL PRESENT
• how is energy transferred between organisms? consumers then eat PRODUCERS. when the organism RESPIRES the energy stored in its food is transferred in the production of ATP. the organism grows and it’s BIOMASS increases.
• what is the difference between a decomposer and detritivore?

  DECOMPOSERS:

  • MICROORGANISMS- fungi and bacteria
  • BREAK DOWN or DECAY dead organic material at a microscopic level
  • break down FECES and URINE
  • decomposition releases NUTRIENTS which recycles them
  • also known as SAPROPHYTES
• what is the difference between a decomposer and detritivore?

  DETRITIVORES:

  • small ANIMALS
  • SPEED up decomposition as BREAK organic material into SMALLER pieces which creates a LARGE SURFACE AREA for decomposers to work on
• how do decomposers release nutrients?

  • bacteria and fungi release ENZYMES which BREAKS DOWN organic material
  • they ABSORB soluble nutrients and use them for GROWTH and as an ENERGY STORE
  • these decomposers are EATEN by other ORGANISMS which passes on nutrients
  • some nutrients are released directly into the SOIL or ENVIRONMENT
• orangutans are an endangered species. the main reason for this is HABITAT loss.
• Even without human interference, ecosystems are constantly changing.
• What factors affect an ecosystem?

  the factors that affect an ecosystem can be divided into two groups:

  biotic factors and abiotic factors
• biotic factors: the LIVING factors

  eg. in a woodland, the presence of trees, squirrels and hedgehogs are biotic factors. the numbers of the organisms are also biotic factors
• abiotic factors: the NON LIVING or PHYSICAL factors.

  eg. within a woodland system, abiotic factors would include the amount of rainfall received and temperature of the ecosystem
• BIOTIC FACTORS:

  normally refers to the interactions between organisms or those which have once lived
• BIOTIC FACTORS:

  many organisms COMPETE for factors such a FOOD, SPACE and BREEDING partners.
• BIOTIC FACTORS:

  competition is the most common biotic facto. if a food supply is limited this limits the number of organisms that can feed on it
• BIOTIC FACTORS:

  the number of a certain species in the ecosystem eg. number of squirrels in a woodland system
• BIOTIC FACTORS:

  predation
• BIOTIC FACTORS:

  disease
• abiotic factors:

  • amount of rainfall
  • temperature
  • light intensity
  • the pH of the soil
• LIGHT INTENSITY:

  Light is required for photosynthesis. in general the greater the light availability, the greater the success of a plant as it make more glucose for growth
• LIGHT INTENSITY:

  Plants evolve to grow successful in different light intensities. for example, plants in areas of low light intensities often have larger leaves to increase surface area and are darker with more chlorophyll
• TEMPERATURE:

  temperature has its greatest effect on the enzymes that control chemical reactions.
• TEMPERATURE:

  plants develop more rapidly in warmer temperatures as their metabolism will be faster. This is also true for cold blooded animals like lizards, which rely on the sun to warm them up
• TEMPERATURE:

  Warm-blooded animals (endotherms) are less affected by their external environment
• MOISTURE LEVEL:

  for most plant and animal species, a lack of water leads to death.
• MOISTURE LEVEL:

  A lack of water causes most plants to wilt because water is needed to keep the cell turgid, which keeps the plant upright. Water is also required for photosynthesis
• SOIL PH:

  the pH of soil affects the biological activity in soil and the availability of certain MINERALS
• SOIL PH:

  Some plant species grow better in acidic soils eg. ferns and rhododendrons
• SOIL PH:

  some plants grow better in alkaline soils eg. cucumbers and cauliflower
• LIGHT INTENSITY

  MEASURED USING LIGHT METER

  UNIT: LUX