Chapter 17 - Organising an ecosystem Flashcards
what are producers?
organisms that take in energy from the sun and provide food for other animals
why is green algae a producer?
it absorbs light from the sun for photosynthesis, creates glucose for itself so it grows and is then eaten by other animals, transferring its biomass
what are the main producers in the ocean? 2
algae and phytoplankton
what are primary consumers?
the animals that eat the producers
what type of animals are primary consumers?
herbivores
what are secondary consumers?
animals that eat other animals (the primary consumers)
what type of animals are secondary consumers?
carnivores
what are tertiary consumers?
very large carnivores that eat the secondary consumers
problems for primary consumers
it is difficult to break down cellulose
must break down cell wall to get to contents
it is sometimes difficult to find enough plant material to survive
main problem for secondary and tertiary consumers
animals move around - they must hunt
cycle of predators and prey in a stable community
if there is lots of food available, the number of prey increases as they can grow and breed successfully
plenty of food available for predators, so they breed and grow successfully, their populations increase
a large number of predators = less prey so their number falls
fewer prey = predators numbers fall
fewer predators allow prey to breed and grow successfully - their numbers increase
what are the decomposers?
a group of organisms that break down animal waste, dead animals and plants
what 4 chemicals are living things mainly made from?
hydrogen
carbon
oxygen
nitrogen
what does the decay process do?
it ensures that any elements taken out of the ecosystem by an organism in its lifetime are returened
why is it important that nitrogen and carbon dioxide are returned to the environment?
plants use nitrogen for growth and carbon dioxide for photosynthesis
process of the water cycle
energy from the sun makes water evaporate
it condenses as it rises to form clouds
water falls from clouds as precipitation
animals drink water
released from animals, eg respiration/urinating
drains into sea
process repeats
what are all the main molecules in our bodies made from?
carbon mixed with other elements
why is the carbon cycle under threat?
as we release more fossil fuels into the air, there are fears that the carbon cycle may not be able to regulate itself
what are carbon sinks?
large stores of carbon that are only released when we burn them
