5.1 - The Role of Organisms
An organism that makes their own food is called?
A Producer
What is a food web?
A food web is a model that shows how nutrients/energy pass between organisms. Organisms are more interconnected in food webs than in food chains, and may share multiple food sources.
How much energy is passed between organisms on the food chain?
10%
What is matter?
Matter is anything that occupies space and has a mass.
What is crop rotation?
Cropped rotation is the planned growing of different crops year after year to get better results.
A carnivore that feeds on already dead animals is called a _______?
Scavenger
What is the initial source of the energy in all food webs and food chains?
The Sun! Producers use energy in sunlight to make food and the rest of the food chain is dependent on producers.
What is a pyramid of numbers?
A pyramid of numbers is an ecological model that shows the total number of organisms at each level of a food chain or food web.
What is a closed system?
A closed system is an environment in which no matter can enter and no matter can leave.
What makes an ecosystem sustainable?
A sustainable ecosystem has enough resources/nutrients for the biotic components of the ecosystem to survive and flourish.
Producers make their own food through what process? Explain how this process works.
Photosynthesis!
Carbon dioxide (from the air) + water (from the soil) + Energy from the sun = oxygen + nutrients (sugars)
What happens when you eliminate one species from the rest of a food chain/web? Provide an example.
It causes changes in other parts of the food web. For example, if your producer population declined, it would cause the population of herbivores who eat them to decline. This would affect the carnivores who eat those herbivores, causing a ripple effect throughout the rest of the chain. Animals would move away, find new food sources (resulting in competition), or die off.
Explain how energy is used within an organism.
1. Some of the energy is used for the organism's life functions
2. Some of the energy is stored for maintenance and repair
3. Some of the energy is not useable and passes out of the organism as waste.
Describe the 3 steps involved in the water cycle.
1. Evaporation - the change of state from liquid to gas. This occurs when water on earth is turned into water vapour in the atmosphere.
2. Condensation - the change of state from gas to liquid. Water vapour rises in the atmosphere and condense to form tiny droplets. This is also the stage where cloud formation occurs.
3. Precipitation - water droplets fall to the ground as rain or snow.
What does the statement "matter moves through the environment" mean? Give an example.
The flow of matter doesn’t happen all in one place. Matter can be taken from one place in an ecosystem and brought to a new place.
i.e. A bear eats blueberries by the river. The bear goes on a walk and poops the blueberry seeds out in a forest. New blueberry plants will now grow in that forest.
What are the 3 types of consumers. Explain what each consumer eats.
1. Herbivore - a consumer that only eats plants
2. Omnivore - a consumer that eats plants and animals
3. Carnivore - a consumer that only eats animals
Label the trophic levels in the following food chain: Dandelion, aphid, ladybug, robin, hawk.
What happens to the total number of organisms at each level of a pyramid of numbers? Why does this occur?
The total number of organisms at each level decreases as you move up the pyramid. This occurs because only about 10 % of the energy stored in the bodies of the organisms at each level is available to the organisms at the next highest level.
List 2 ways that animals contribute to the carbon cycle.
Animals release carbon dioxide when they exhale.
Animals release carbon dioxide into the earth during decomposition.
Describe the nutrient cycle (how nutrients flow within ecosystems/between organisms).
Decomposers release nutrients when they break down dead organisms
The nutrients are added to the soil
Plants suck up the nutrients from the soil using their roots
The nutrients pass on to the primary consumers when they eat plants
The nutrients pass on to the higher-level consumers when they eat the lower-level consumers
When living things die, the cycle repeats as decomposers break down the dead organisms
Explain the similarities and differences between detrivores and decomposers
Similiarities: Both detrivores and decomposers feed on dead organisms and waste.
Differences: Detrivores break them down organisms into smaller pieces of decayed matter. Decomposers break them down into simple substances like nutrients. Detrivores have a waste/digestive system, decomposers do not.
Explain what happened in Borneo. How does the case in Borneo show the importance of understanding food webs/chains?
In Borneo, they used a pesticide called DDT to try to lower the number of mosquitoes because they caused malaria. The DDT did lower the number of mosquitoes, however, the number of cockroaches also declined. Cockroaches are the main food source for lizards. Without their food source readily available, the lizard population began to decline as well. The lizards were the food eaten by cats. Cats also ate rats. With a decline of its food source, the number of cats also declined. Because the number of cats declined, the rat population increased drastically. This was a huge issue because the increased rat population caused a number of epidemics. In order to deal with this problem, the country had to import cats to eat the rats.
What does an ecological pyramid need to maintain a stable population in an ecosystem?
To maintain stable populations in an ecosystem, there must be a large number of producers to provide enough food energy for primary, secondary, and tertiary consumers. The wider the base of the pyramid, the more consumers can live in the ecosystem.
How do fossil fuels get formed?What happens when they get burned?
Fossil fuels are formed by the remains of organisms which do not decompose completely underground. Fossil fuels can remain underground for millions of years.
Carbon enters the atmosphere more quickly when fossil fuels are burned by humans.
List some of the benefits of crop rotation. Explain how these benefits occur.
Crop rotation can reduce weed, pest, and disease problems because the nutrients they feed off of are constantly being rotated/switched out.
Planting different crops can provide good nutrients to the next crop.