Ecosystems Flashcards
What do organisms need to stay alive?
Resources
What do plants need to stay alive?
Light, water, carbon dioxide, oxygen, warmth and mineral ions.
What do animals need to stay alive?
Oxygen, food, water, shelter
What is an ecosystem?
An area in which all the living organisms and all the non-living physical factors form a stable relationship that needs no input from outside the area to remain stable./ All the organisms and the environment they live in.
What do all the organisms that live and interact in an ecosystem form?
A community
What is the community in an ecosystem made up of?
The community is made up of populations of different species. These species depend in each other for resources, so we say they are interdependent
Each population lives in a particular habitat in an ecosystem. What does a habitat include?
A habitat includes the other organisms that affect the population and the local environment.
What does interdependent mean?
When organisms in an area need each other for resources
Why are organisms continually interacting with each other and their environments?
Because they rely on each other for resources.
What is abundance?
Abundance is a measure of how common something is in an area, such as its population size.
Measuring population size by counting all the organisms in an area is often impossible. How can you estimate the population size?
By taking a sample using a quadrats. Quadrats are placed randomly in the area, and the number of individuals in each quadrat is counted.
What is the equation to work out population size?
Number of organisms in all quadrats ✖️ total size of an area where organisms live ➗ total area of quadrats
What is a food web?
A food web shows the feeding relationships between the organisms in a community.
What can we use a food web for?
To predict what will happen if there are any changes in the ecosystem.
What is the order of a food web?
Producer Primary consumer/ herbivore Secondary consumer/ carnivore/ predator Tertiary consumer/ carnivore/ predator Top predator
Each year, over the whole earth, photosynthesis capture 3 X 10 to the power of 20 J of energy transferred by light from the sun. Much of this energy is transferred to substances in new plant biomass (the mass of tissues). Where is the rest transferred to?
The rest is transferred to the environment by heating, during processes such as respiration. Other organisms cannot make use of energy transferred to the environment by heating and so these energy transfers are less useful for living things.
Describe trophic levels
Energy is stored in plant (producer) biomass when it is transferred to a herbivore (primary consumer). The energy stored in the herbivore is then transferred to the carnivore (secondary consumer) that eats it, and so on through the trophic levels (feeding levels) of a food chain. We can this of this as energy flow though the biotic components of an ecosystem. At every trophic level the energy decreases, as some energy is wasted. At every trophic level the consumer needs to eat more to make up for the lost energy.
How can you show the energy transfers of an organism?
Through a sankey digram
What equation do you use to calculate the efficiency of energy transfers?
Energy transferred to biomass ➗ total energy supplied to organism
Efficiencies are usually given on a scale from 0-1 with 1 being complete efficiency. These values can be converted to percentages by multiplying by 100.
If we measure the biomass of all the organisms at each trophic level in an ecosystem, what can we display it in?
A pyramid of biomass. This kind of diagram usually has a pyramid shape because energy is transferred from the food chain to the environment at each trophic level. With less energy available, less biomass can be produced. We can calculate the percentage transfer of biomass between tropic levels in a pyramid of biomass. There is a maximum length of food chain in an ecosystem. The pyramid shape helps to explain why there is a limit. The energy stored in the biomass of the top trophic level is too little to support another level.
The distribution of organisms is where they are found in an ecosystem. What can distribution be affected by?
Distribution can be affected by physical and chemical factors, such as temperature, rainfall and substances in the soil. These non-living factors are called abiotic factors. The effect of abiotic factors on the distribution of organisms can be measured using a belt transect. If abiotic factors change, then the distribution of organisms may also change.
Quadrats are placed along a line in a habitat, and the abundance of organisms is measured as well as the abiotic factors in each quadrat position. What does changes in abundance show?
Changes is abundance can show which abiotic factor has the greatest effect on the organisms.
Each species of organism has certain adaptations, what does this mean?
The organism is suited to particular conditions.
What are the consequences of of climate change on organisms?
Few organisms can survive drought (lack of water) for long. Most land plants cannot survive if their roots are under for long. If the climate changes resulting in more flooding or more drought, then many species in different communities may die out.
How do temperatures affect the distribution of organisms?
All organism have adaptations that make them suited to life at particular temperatures. A long-term rise or fall in temperature in an ecosystem will change the distribution of some organisms and so affect the whole community.
Light is essential for plants and algae to grow.
In the oceans, most algae can only get enough light within 30m of the surface. On land, light is limited within forests. In dense forests, few plants can grow on the forest floor.
Substances that cause harm in the environment are pollutants and cause pollution. Many human activities release pollutants. What are the effects of this?
These can poison organisms or cause harm to organisms in other ways (such as plastics being eaten by fish and other organisms).
Describe the method of the core practical - quadrats and transects.
Peg out a long tape measure (at least 20m) on the ground, starting where there is no shade and ending in heavy shade. This is the transect line.
You will need to make measurements at regular intervals along the transect line. Decide on you measure meant intervals, which may depend on how long the line is and how much time you have to record information.
Measure the abiotic factors at each point and record them.
Record the abundance of your selected plants in the quadrat.
Repeat till you get to the end of you transect line.
What are biotic factors?
Living organisms in an ecosystem, they affect other living organisms
How do biotic factors affect each other?
Organisms have to compete with each other for food.
Some organisms eat each other.
There is lots of competition in the ecosystems.
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In large communities, many biotic factors may affect predator and prey numbers. However in small communities, the number of a predator and its prey may be closely related in its what?
Predator-prey cycle
What is a predator-prey cycle?
The regular variation in numbers of predator and prey within a feeding relationship
What is biodiversity?
The variety of species in an area.
What is lecanora conizaeoides?
It is a specie of lichen that grows on trees and buildings. Like all lichens, it is a mutualistic relationship between a fungus and an alga. Until about the last 20 years, it was the only lichen found in city centres and industrial areas. This is because it is the only lichen that can tolerate air polluted with sulfur-containing gases from burning fossil fuels. So this lichen can be used as an indicator specie for sulfur dioxide pollution in the air.
Over the past 50 years, there has been a large fall in sulfur dioxide pollution in the air, and this has affected where the lichen lecanora conizaeoides is found. Why has the distribution of other lichen species also changed?
Because the levels of other pollutants have changed.
What is blackspot fungus and what does it indicate?
Blackspot fungus is a pathogen of roses and it indicates air pollution. The fungus cannot grow well where there is a lot of sulfur pollution. So, roses growing in cities rarely suffered from blackspot infection.
What can water pollution be caused by!
Poisonous substances released by factories such as mixers or detergents. Also fertilisers and sewage.
How are some aquatic species of invertebrates useful pollution indicators?
Substances in the pollution cause eutrophication, which encourages the rapid growth of algae and plants. The bacteria that feed on the dead plants and algae then reduce the oxygen concentration in the water, which kills many animals. Different aquatic invertebrates are adapted to different concentrations of oxygen.
How can water and air pollution be measured?
Using sensors. These give numerical data at the time of the measurement. Pollution indicator species do not give this level of detail in measurement, but they are useful as a simple assessment of the long-term health of an ecosystem.
What is parasitism?
It is a kind of feeding relationship where a parasite benefits by feeding off a host organism, causing harm to the host. The parasite lives in or on the host. The host may survive for a king time and continue to provide food for the parasite if the parasite causes limited harm.
Some parasites, such as lice, live in the outside of their hosts. Others such as tapeworms, live inside. What do all parasites have to help them survive in or on their host.
Adaptations
What are the adaptations do tapeworms have to live inside their host?
Hooks and suckers attach the worms head firmly to the hosts intestine wall.
Segments contain male and female sex organs so fertilisation can occur.
A flattened body allows absorption of nutrients over a whole surface without need for digestive or circulatory systems.
What adaptations do headline have to live on their host?
Sharp mouthparts can pierce skin and suck blood.
Sharp claws grip on to hair and skin.
Eggs are glued to hairs to prevent them falling off.
What is a mutualistic relationship?
A relationship where organisms live together to benefit each other. Eg many flowers depend on insects for pollination. The flower benefits by being ab,e to produce fertilised egg cells, and the insect benefits by collecting nectar or pollen from the flower which it needs for food.
How do sea anemone’s and clownfish have a mutualistic relationship?
A sea anemone’s stinging tentacles protect clownfish from predators. Clownfish chase off the predators of the anemone and provide nutrients in their faeces, which help the anemone to grow.
