Life on Earth Flashcards
What is a species?
A species is a group of organisms with similar characteristics that interbreed to produce fertile offspring.
What is biodiversity?
Biodiversity refers to the number and abundance of species in an area. Ecosystems can have higher biodiversity e.g. rainforest or lower biodiversity e.g. desert
What is a population?
A population is all the animals or plants of one species living in a particular area.
What is a producer?
A producer is an organism that is able to produce its own food e.g. plants
What is a consumer?
A consumer is an animal that must eat food in order to get its energy.
What is a herbivore?
A herbivore is a consumer that eats plants e.g. cow.
What is a carnivore?
A carnivore is a consumer that eats other animals.
What is an omnivore?
An omnivore is a consumer that eats a mixture ofplants and animals e.g. bear
What is a predator?
A predator is an animal that hunts other animals.
What are prey species?
A prey species is the animal that is hunted by a predator.
What is an ecosystem?
An ecosystem consists of all the organisms (the community) living in a particular habitat and the non-living components with which the organisms interact. Ecosystem = community + habitat
What is a community?
A community is all the populations of organisms in a particular habitat.
What is a habitat?
The habitat consists of all the non-living components with which organisms interact.
What is a food chain?
A food chain is a diagram which shows the feeding relationships of organisms living together in a particular habitat.
What does a food chain always begin with?
A food chain always starts with a producer followed by two or three consumers.
What do the arrows in a food chain represent?
The arrows in a food chain show the direction of the flow of energy.
What is a food chain?
A food web is made up of lots of food chains put together.
Describe the predator prey cycle in terms of changes in population sizes over time.
As a prey species number increases the number of predators also increases, until there are too many predators. Then the number of prey species will begin to decrease resulting in the predator numbers also decreasing. Then the cycle begins again.
What does niche mean?
A niche is a role an organism plays within a community. It relates to the resources it requires e.g. light and nutrients and its interactions with other organisms in the community. It involves competition and predation and the conditions it can tolerate such as temperature.
Give 4 resources that organisms may be in competition for.
Organisms will compete for resources they need to survive including:
1. sunlight
2. water
3. food
4.mates
What is interspecific competition?
Interspecific competition is competition between organisms of different species e.g. zebra and giraffe compete for grass.
What is intraspecific competition?
Intraspecific competition is competition that occurs between organisms of the same species e.g. two male lions competing for access to the female lions.
Which type of competition is the most intense and why?
Intraspecific competition is more intense due to the individuals of the same species having exactly the same requirements.
How can organisms be identified?
Organisms can be identified using a paired statement key.
How can plants and slow or non-moving organisms be sampled?
Plants can be sampled using a quadrat.
Give 2 ways the estimate produced from use of a quadrat be made more accurate?
- Ensure enough quadrats are counted to ensure the results represent the area sampled.
- Use a random number generator to make sure the entire area investigated is represented and to eliminate bias..
How can invertebrates be sampled?
Invertebrates can be sampled using a pitfall trap.
How can the results of pitfall traps be improved?
- Cover the pitfall trap loosely to hide the insects from predators and to exclude water.
- Ensure the pitfall trap is flush with the soil so invertebrates enter easily.
- Set enough pitfall traps to make sure the results represent the area sampled.
What is a biotic factor?
Biotic factors are living factors that can influence population sizes and biodiversity in an ecosystem.
List 5 biotic factors.
- Predation
- grazing
- competition
- disease
- food availability
Which biotic factors decrease biodiversity?
Competition, disease, lack of food and predation all reduce biodiversity.
Which biotic factor increases biodiversity?
Grazing increases biodiversity because it keeps the dominant fast growing plants under control and allows the smaller plants to grow.
What are abiotic factors?
Abiotic factors are non-living (physical) conditions which can affect biodiversity.
List 4 abiotic factors?.
- Light intensity
- Soil moisture
- pH
- Temperature
Describe how to measure light intensity.
Use a light meter and angle it towards the light source (sun). Make sure that you are not blocking the sun from the sensor on the meter.
Describe2 ways to measure soil pH.
- Use a soil pH meter to measure soil pH. Make sure the probe is placed into the soil deep enough and that the probe is cleaned between uses.
- Mix a soil sample with water. Filter the sample and then test the filtrate with universal indicator to determine the pH.
Describe how to measure soil moisture level.
Use a soil moisture meter to measure soil moisture. Make sure the probe is placed into the soil deep enough and that the probe is cleaned between uses.
Describe how to measure temperature.
Use a thermometer.
Describe how soil moisture can have an affect on where a plant species may grow.
Some plant species can only grow in areas with high soil moisture levels. These species will not be found in areas where the soil moisture levels are too low.
What is an indicator species?
An indicator species is an organism whose presence or absence gives information about the level of pollution in the environment.
What organism is used as an indicator of air quality?
Lichens. The presence of a wide variety of lichen species indicates low sulfur dioxide levels in the air.
Which organisms indicate low oxygen levels in fresh water?
Bloodworms, sludgeworm, rat-tailed maggot.
What is photosynthesis?
Photosynthesis is the process by which green plants make their own food. Carbon dioxide from the air and water from the soil are combined in the presence of light energy to produce sugar (glucose) and oxygen.
What are the raw materials required for photosynthesis?
Carbon dioxide and water.