Ecology Flashcards
What is the source of energy for most living organisms?
Radiation from the Sun
What percentage of the incident energy from light is transferred for photosynthesis?
1%
Where is this incident energy stored?
In the substances that make up the cells of plants
The further up a food chain (trophic level)…
The less energy and less biomass
What do pyramids of biomass show?
The relative mass of living material at a tropic level (i.e. how much all the organisms would “weigh” if you put them all together)
How much of biomass from each trophic level is transferred to the level above it?
Approximately 10%
Why is biomass lost between each trophic level (energy wasted)?
- Organisms don’t eat very single part of organism they’re consuming
- Don’t absorb all stuff in food they ingest (egested as faeces) - lost in organisms’ waste materials
- Some biomass is converted into other substances that are lost as waste
Give an example of some biomass being converted into other substances and that are lost as waste
Organisms use a lot of glucose in respiration to provide energy for movement and keeping warm (rather than make more biomass) + energy from respiration is transferred by heating surroundings
What does respiration produce as waste?
Carbon dioxide and water
Give another example of some biomass being converted into other substances and that are lost as waste (that’s not to do with respiration)
Urea is waste - released in urine with water when proteins in biomass are broken down
How can you calculate the efficiency of a biomass transfer?
Biomass transferred to next level
——————————————————— x 100
Biomass available at the previous level
How can the efficiency of food production be improved?
By reducing the number of stages in a food chain
What does a food chain show?
Shows what’s eaten by what
Plants make glucose by photosynthesis. Some glucose produced is used to make other biological molecules in plant. What are these molecules known as?
The plant’s biomass
What is biomass and what can it be thought as?
It is the mass of living material
Can be thought as energy stored in plant
How is energy is transferred through living organisms in an ecosystem?
By organisms eating other organisms
Populations of prey and predators go in…
cycles
What is the population of any species limited by?
The amount of food available
Explain how populations of prey and predators go in cycles
- If population of prey increases = population of predators will increase
- However, as population of predators increases, number of prey will decrease
Why are predatory-prey cycles always out phase with each other?
Because it takes a while for one population to reasons to changes in other population
E.g. When number of rabbits goes up, number of foxes doesn’t increase immediately because it takes time to reproduce
How can we increase the efficiency in food production? (e.g. with livestock)
- Can limit movement of livestock
- Keep them in a temperature-controlled environment
= reduces transfer of energy from livestock to environment
How does limiting the movement of livestock/controlling the temperature make farming more efficient?
- Animals use less energy moving around & controlling their own body temperature
- Means more energy is available for growth = more food can be produced from same input of resources
What is intensive farming?
Where animals are restricted and kept in confined spaces
Name 3 advantages of intensive farming
- More biomass and energy in animals
- Mass production = more profit
- Free from predators
- Cheaper?
Name 3 disadvantages of intensive farming
- More disease is likely to spread
- Animal behaviour can change
- Morally wrong
What are extremophiles?
Organisms that live in environments that are very extreme
How are materials (e.g. carbon, oxygen, hydrogen) that are removed from the environment (by living organisms for growth, etc) returned to environment?
In waste products or when organisms dies and decays
Why do materials decay?
Because they’re broken down by microorganisms
Decay happens faster in what conditions i.e. when are microorganisms most active?
- Warm
- Moist
- Aerobic (oxygen rich) - to respire
How is CO2 removed from atmosphere?
By green plants and algae during photosynthesis
What is carbon used in plants for?
To make glucose = (carbon) turns into carbohydrates, fats and proteins which make up bodies of plants and algae
How is carbon returned back to the atmosphere? Two ways
- When plants and algae + animals + microorganisms respire, carbon is returned to atmosphere as CO2
- Combustion of wood and fossil fuels also release CO2 back into air
How does carbon move though the food chain?
- When plants and algae are eaten by animals some carbon becomes part of fats and proteins in body
- When plants, algae, animals die: other animals and microorganisms feed on remains
What is name of animals that eat other dead animals?
Detritus feeders
What is animals’ waste broken down by?
Detritus feeders and microorganisms
What is the carbon cycle?
The constant cycling of carbon
Decay processes release substances…
that plants need to grow
What is compost?
Decomposed organic matter (e.g. food waste)
What can compost be used as?
Used as national fertiliser for crops & gardens
What are responsible for decomposition (decay)?
Microorganisms (e.g. bacteria and fungi) & detritus feeders
What is the rate of decay affected by? (name 4 things)
- Oxygen Availability
- Water Availability
- Temperature
- Number of Decay Organisms
Explain how oxygen availability affects the rate of decay (or may not)
Many organisms need oxygen to respire = need to do to survive
But microorganisms involved in anaerobic decay = don’t need oxygen
Explain how water availability affects the rate of decay
Decay takes place faster in moist environments bc organisms involved in decay need water to carry out biological processes
Explain how temperature affects the rate of decay
Warmer temperatures = things decompose quicker bc they increase rate that enzymes involved in decomposition work at
If it’s too hot, what happens to decomposition and why?
Decomposition slows down or stops bc enzymes are
denatured & organism dies
If it’s too cold, what happens to decomposition?
Slows down
Explain how the no. of decay organisms affects the rate of decay
More microorganisms and detritus feeders there are = faster decomposition happens
What is a habitat?
Place where an organism lives
Define community
The populations of different species living in a habitat
Define population
All organisms of one species living in a habitat
Define ecosystem
The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment
What are biotic factors?
Living factors of environment
What are abiotic factors?
Non-living factors of the environment
What do plants compete for? (name 4 things)
- Space
- Light
- Water
- Mineral ions (nutrients)
What do animals compete for? (name 4 things)
- Space (territory)
- Water
- Food
- Mates
What are adaptations?
Features or characteristics that helps organisms to survive
Why do artic animals have white fur?
To camouflage: helps avoid predators and sneak up on prey