b17 - organising an ecosystem Flashcards
how can green plants and algae photosynthesise?
use sunlight as a source of energy
how are plant cells made?
glucose from photosynthesis is synthesised into other compounds to make plant cells
- new material adds to biomass of organism
how do food chains begin?
plants are producers of biomass and start a food chain
what animals eat producers?
- primary consumers
- e.g: herbivores like sheep or fish that eat phytoplankton
what eats primary consumers?
secondary consumers
- animals such as seals or lions
what are secondary consumers eaten by?
tertiary consumers
how can we present feeding relationships in a community?
food chains
why do primary consumers need to eat a lot of plant material?
- cellulose is difficult to digest so they have to eat enough to gain enough nutrients
- plants stay in one place so consumers dont expend energy chasing them
what are secondary and tertiary consumers known as?
predators because they have to catch their food
what happens to number of predators and prey in a stable community?
numbers rise and fall in cycles
how is glucose made for animas to eat?
- carbon (abiotic) is taken in by plants and converted to glucose (biotic)
- plants take mineral ions from soil (abiotic) and these, with glucose, enter animals when plants are eaten (biotic)
why must materials be returned to the environment?
for use by future organisms
how are materials returned to environment?
- trees shed leaves
- animals produce droppings
- eventually all organisms die
define decomposers and give two examples
- break down waste material and dead organisms
- bacteria and fungi
what do detritus feeders do (e.g maggots, worms)?
start process of decay by eating waste of dead organisms
what do decomposers do after detritus feeders?
digest dead animals, plants and detritus feeders, returning carbon dioxide, water and mineral ions to environment
what is the main point of the water cycle?
provides fresh water for animals and plants on land before draining into the seas and oceans
give the process of the water cycle
- water evaporates constantly from land surface, rivers and seas
- as water rises into cooler air, it condenses, forming clouds, and is then precipitated back into the surface as rain, snow, hail or sleet
- water passes through animals and plants then released during respiration and decay
- water also lost through urine, faeces and sweat
- plants release water into atmosphere during transpiration
give key stages of water cycle
1) condensation
2) precipitation
3) evaporation
4) transpiration
5) respiration
what does the carbon cycle involve?
photosynthesis and respiration
what does photosynthesis do?
removes carbon dioxide from the atmosphere which is used to make organic molecules (carbs, fats and proteins)
how is carbon dioxide returned back to atmosphere?
green plants and algae respire
how is carbon dioxide released into the atmosphere?
when humans cut down and burn trees (combustion)
why do animals have carbon in their bodies?
from eating green plants
