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B7 A) Ecology
B7 A) Ecology
A habitat is where organisms live. The population of an organism is all of the members of a single species living in a habitat; the population of rabbits would be all of the rabbits living in a habitat. A community is two or more populations of organisms living in a habitat.
An ecosystem is the interaction between the living organisms (biotic) and non-living (abiotic) parts of their environment. The living parts of an ecosystem are known as biotic and they include plants and animals. The non-living parts of an ecosystem are known as abiotic and they include the soil, light, moisture and climate/ temperature of an area.
An ecosystem is the interaction between the living organisms (biotic) and non-living (abiotic) parts of their environment. The living parts of an ecosystem are known as biotic and they include plants and animals. The non-living parts of an ecosystem are known as abiotic and they include the soil, light, moisture and climate/ temperature of an area.
Different Levels in an Ecosystem
Organisms within an ecosystem are organised into producers and consumers.
Producers
Producers are organisms that use sun light to produce food. They produce food (glucose) by photosynthesising; the equation for photosynthesis is: carbon dioxide + water –> glucose + oxygen. Some of the glucose made by the producers during photosynthesis is turned into other biological molecules in the producer (such as amino acids, cellulose, starch etc). Producers are usually green plants or algae.
Consumers
Consumers are organisms that gain energy from eating producers or other consumers. Organisms that eat producers (plants or algae) are known as primary consumers; these are herbivores and an example could be blackfly larvae that eat algae.
Secondary consumers are organisms that eat primary consumers. Secondary consumers are carnivores as they eat other animals/ consumers. If we continued the blackfly larvae example, a secondary consumer would be a water spider because water spiders eat black fly larvae. The organism doing the eating is known as the predator, and the organism that is being eaten is known as the prey. In this example, the water spider is the predator and the black fly larvae are the prey.
Tertiary consumers are organisms that eat secondary consumers (they are also carnivores). An example would be a frog that eats water spiders.
Organisms within an ecosystem are organised into producers and consumers.
Producers
Producers are organisms that use sun light to produce food. They produce food (glucose) by photosynthesising; the equation for photosynthesis is: carbon dioxide + water –> glucose + oxygen. Some of the glucose made by the producers during photosynthesis is turned into other biological molecules in the producer (such as amino acids, cellulose, starch etc). Producers are usually green plants or algae.
Consumers
Consumers are organisms that gain energy from eating producers or other consumers. Organisms that eat producers (plants or algae) are known as primary consumers; these are herbivores and an example could be blackfly larvae that eat algae.
Secondary consumers are organisms that eat primary consumers. Secondary consumers are carnivores as they eat other animals/ consumers. If we continued the blackfly larvae example, a secondary consumer would be a water spider because water spiders eat black fly larvae. The organism doing the eating is known as the predator, and the organism that is being eaten is known as the prey. In this example, the water spider is the predator and the black fly larvae are the prey.
Tertiary consumers are organisms that eat secondary consumers (they are also carnivores). An example would be a frog that eats water spiders.
Food Chain
We can draw a food chain for the algae, blackfly larvae, water spiders and frogs. This food chain is shown below.
We can draw a food chain for the algae, blackfly larvae, water spiders and frogs. This food chain is shown below.
The different organisms in a food chain are known as trophic levels. There are 4 different organisms in this food chain, so there are 4 different trophic levels.
The arrows in food chains show the direction of energy transfer. When the blackfly larvae eat the algae, energy is transferred from the algae to the blackfly larvae. When the water spiders eat the blackfly larvae, energy is transferred from the blackfly larvae to the water spiders.
Biomass measures the mass of all living material at each stage of the food chain. The biomass of the algae will be the mass of all of the algae in this food chain. The biomass decreases as we move through the food chain. One reason for this is because some of the organism that has been eaten is indigestible (bones) or lost through waste material. Another reason is that some of the energy is used for respiration reactions, which the organism uses for movement and maintaining a constant internal temperature. Usually less than 10% of the biomass is passed onto the next trophic level.
We will be looking at food chains again in a later section.
The arrows in food chains show the direction of energy transfer. When the blackfly larvae eat the algae, energy is transferred from the algae to the blackfly larvae. When the water spiders eat the blackfly larvae, energy is transferred from the blackfly larvae to the water spiders.
Biomass measures the mass of all living material at each stage of the food chain. The biomass of the algae will be the mass of all of the algae in this food chain. The biomass decreases as we move through the food chain. One reason for this is because some of the organism that has been eaten is indigestible (bones) or lost through waste material. Another reason is that some of the energy is used for respiration reactions, which the organism uses for movement and maintaining a constant internal temperature. Usually less than 10% of the biomass is passed onto the next trophic level.
We will be looking at food chains again in a later section.