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
4 carbon sinks?
fossil fuels
oceans/water
carbonate rocks
the air
what is the carbon cycle?
when carbon is cycled between organisms and the environment
what do plants do with carbon?
they take it from the atmosphere via photosynthesis to make chemicals they need to survive. They are then eaten and carbon is passed along an ecosystem
3 things plants use carbon dioxide to make?
proteins
fats
carbohydrates
how is carbon removed from the atmosphere?
photosynthesis
how is carbon returned to the atmosphere?
respiration
how do decomposers return carbon dioxide to the atmosphere?
when animals and plants die, their bodies are broken down by decomposers
carbon is released as decomposers respire (CO2)
how is human actions contributing to the carbon cycle?
carbon is locked up in trees and fossil fuels
when we burn them, we are releasing CO2 back into the atmosphere
equation for respiration
glucose + oxygen -> CO2 + water
equation for combustion
fossil fuel + oxygen -> CO2 + water
3 environmental factors that can affect distribution of organisms
change in the availability of water
temperature change
change in atmospheric gases
process of the carbon cycle
CO2 is removed during photosynthesis it is used by the plants for growth respiration by plants releases it back carbon moves through food chain respiration by animals releases it back decomposers feed on dead bodies of animals and animal waste - they respire and release CO2 the burning of wood releases CO2
optimum conditions for decay 3
warm
moist
plenty of oxygen
what does decay do?
puts the stuff that organisms took out of the environment back into it
why is temperature important for decay?
warmer temperatures increase the rate that enzymes work at - decomposers work quickly
but, too hot or too cold = no decay
why is moisture levels important for decay?
microorganisms grow better in moist climates and the can digest their food better too
why is oxygen availability important for decay?
most decomposers respire aerobically so need a good supply of oxygen
why is decay important in recycling?
we can make compost which is a fertiliser. It helps plants to grow by giving them extra nutrients
what is produced when bacteria decompose material in anaerobic conditions
methane
main use of methane
burned as a fuel
how does a biogas generator work?
plant/animal waste is put into a tank in anaerobic conditions
the bacteria decompose anaerobically and release methane
optimum temperature of biogas generator
30c
why can biogas generators be used anywhere?
they are exothermic so after the initial energy is supplied, they can heat themselves
under ideal conditions, how much biogas can 10kg of dry dung produce?
3m cubed
why must biogas be used straight away?
it can’t be stored as a liquid as it needs too high a pressure
what are the two types of biogas generators?
batch generators and continuous generators
how do batch generators work?
make biogas in smaller batches
manually loaded up with waste which is left to digest and the by-products are removed at the end of each session
how do continuous generators work?
make biogas all the time
waste is continuously fed in and biogas produced at steady rate
what must a biogas generator have? 3
an inlet for waste to be put in
an outlet for digested material to be removed
an outlet to take the gas to where it is needed
