Ecosystems Flashcards
What is a community?
All the organisms of different species present in a habitat/ ecosystem
What is a population?
All the individuals of one species in a habitat at a given time, that can interbreed to prodice fertile offspring
What in an ecosystem?
The community and abiotic factors of an environment
Describe the two types of competition
Interspecific- competition between different species
Intraspecific- competition between individuals of the same soecies for the same resources
What is a niche?
An organisms role in its ecosystem
Why can no two species occupy the same niche?
There would be too much interspecific competition between the species for the same resources
What is a predator?
An organisms that hunts, kills and eats other organisms (prey)
Explain how the population of prey and predators effects eachother
Their populations fluctuate within narrow limits
If predators increase, more prey are hinted and killed so prey decrease.
As prey decrease, there is less food sources for predators, more intraspecific competition, less reproduction and more mortality. Predator decrease
Prey then increase as less are eaten and more survive and bread
What is the carrying capacity of a species?
The maximum size that a population can remain sustainable in its habitat.
What happens if carrying capacity is exceeded?
The population increases as the environment can no longer sustain the excess numbers
Intraspecific competition increases as respurces become limited to the population
What can cause changes to the population of a species?
Abiotic factors, or interactions between organisms
What are autotrophs?
Primary producers. Energy is transferred from autotrophs to heterotrophs
What are heterotrophs?
Can be primary, secondary or tertiary consumers, energy is transfered to heterotrophs from autotrophs
What are the main trophic levels?
Primary, secondary and tertiary consumers
What is the difference between a food chain and food web?
A food chain is a series of trophoc levels, energy is passed down the trophic levels
A food web is more complex and includes interconnected food chains
What are saproboints? Give examples of them
Organisms that digest dead remains of waste material (detritus) from other organisms. They release inorganic ions and molecules
Bacteria and fungi
How do saproboints digest waste products?
Via extracellular digestion- They secrete enzymes onto the detritus and absorb the digested products
Why is not all energy from the sun used by plants flr photosynthesis?
Some light is not appropriate wavelengths to be absorbed
Light may not be absorbed by photosynthsising parts of the plant
Light reflected or transmitted
Why might not all light used in photosynthesis be converted into energy of glucose?
May be limiting factors of photosynthesis
Energy lost in inefficient reactions in photosynthesis
Why is only 5% of energy produced by photosyntehsis used to make biomass?
Most synthesised sugars are used for respiration
What is biomass?
The mass of organic matter in an organisms
How can you estimate the biomass of a plant?
Collect the plant, including roots.
Weigh the initial mass, then dry it at 80*. Weigh and dry again until the mass stays constant. This is the plants biomass
How can you calculate the energy of biomass?
Use a bomb calorimeter
The dry biomass is burnt in oxygen in the bomb calorimeter and the heat energy given off heats up water
The rise in temperature is used to calculate the energy in calories of the biomass
When estimating biomass, why is it important to dry the material?
The amount of water in any living organisms varies over time
What is production measured in?
KJm-2
What is net orimary production? What is its equation?
The chemical energy store in plant biomass after respiratory losses
= gross primary production- respiration
What is gross primary production?
The chemical energy store in plant biomass, in a given area or volume.
What are the units for productivity?
The units of energy per unit of area or volume
What is the equation for efficiency of energy transfer?
Energy available after tranfer/ energy available before transfer X100
Why might energy transfered between consumers be lost?
• Some food taken in isn’t digested so is lost as faeces
• Some is lost by excretion of metabolic waste products like urea
• Some energy remains in parts of the organism that are not consumed
• Energy lost as heat due to consumer respiration
Hat is the secondary production?
The net production of consumers, after losses of energy between consumers
What is the equation for secondary production?
I (ingested food) -[F (enegy lost in faeces) + R (respiratory losses)]
What are endotherms?
Organisms that maintain a constant body temperature
How can energy transfer be made more efficient in cattle farming?
- Slaughter cattle when still young, so more energy is transferred to biomass
• Feed them on a controlled diet so a higher proportion of digested food is absorbed
• Restrict movement to reduce respiratory losses
• Keep inside so no energy lost to heat, no predators
• Genetically select for higher productivity
What is succession?
The way in which dofferemt species that make up a community change over a oeriod of time
Describe the events of succession
- Pioneer species colonise a hostile environment
- The abiotic environment of the habitat changes
- The changed environment becomes more suitable to support new species
- New plant species increase species diversity, earlier colonisers are replaced by new species
- changes in the abiotic factors again to produce a less hostile environment, increases biodiversity and creates a climax community
What is the difference between primary succession and secondary succesision?
Primary succession occurs where no community has been previously established
Secondary succession occurs in an area that has been previously colognised or disturbed
