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
