Life On Earth Flashcards
What is a species?
A species is a group of organisms which can interbreed to produce fertile offspring.
What is a habitat?
A habitat is the place where an organism lives.
What is a population?
A group of organisms of one species is called a population.
What is a community?
A community is all the living organisms together in an ecosystem.
What is an ecosystem?
An ecosystem consists of all the living organisms (community) in a particular habitat and non-living components with which they interact.
Formula of an ecosystem?
Community + non living components = ecosystem
What are some examples of an ecosystem?
Pond, coral reef, desert, forest, rainforest and swamp.
What is biodiversity?
Biodiversity is the total variation that exists amongst living things.
What is a producer?
Producers are organisms that can make their own food. They are usually green plants.
What is a consumer?
Consumers are organisms that eat other organisms in the food chain (they consume the food).
How many groups can a consumer be split into and state the groups?
A consumer can be split into 3 groups:
Herbivore
Carnivore
Omnivore
What is a herbivore?
A organism that only eats plants.
What is a carnivore?
An organism that only eats animals.
What is a omnivore?
A omnivore is an organism that eats both plants and animals.
What two categories are animals split into?
Predators and prey.
What is a predator?
A predator is an animal that hunts.
What is a Prey animal?
Prey are animals that are hunted.
What are prey animals and what are predator animals?
Prey animals are usually the primary consumer while predators are usually the secondary consumers.
What is the feeding relationship called?
A food chain.
What do the arrows in a food chain show?
The arrows show the direction of the energy flow.
Give an example of a food chain?
Grass —> rabbit —> Fox
What is a food web?
A food web is a diagram that shows interconnecting food chains
What is a niche?
A niche is the role that an organism plays within a community.
What does a niche relate to?
It relates to the resources an organism requires in an ecosystem such as: light,nutrients availability, competition, predation, temperature and interactions with other organisms.
When does competition occur?
Competition occurs between plants and animals in an ecosystem when resources are in short supply.
What sort of things do animals compete for?
Mates, space, water and food.
What do plants compete for?
Light, water, space and nutrients.
What happens to an organism if it is not successful during competition for food?
They will die.
Which type of competition is more intense?
Infraspecific competition between members of the same species. (Members of the same species require the same resources).
What are some limiting factors for animals?
Water, food, mates and space.
What are limiting factors for plants?
Water, light, nutrients and space.
What is interspecific competition?
Occurs amongst individuals of different species for one or a few of the same resources they require.
What is Infraspecific competition?
Occurs amongst individuals of the same species and is for all resources.
Inter?
Different
Intra
Same.
What are quadrats used to sample?
Quadrats are used to sample plants and slow moving animals.
What is a source of error with quadrats?
The sample taken may not be representative of the whole ecosystem.
How can you solve the error with quadrats?
Quadrats should be placed randomly and many quadrats should be placed (repeat= reliability)
What are pitfall traps used for?
Pitfall traps are used to sample small invertebrates living on the ground.
What are some source of errors with pitfall traps?
Sample taken may not be representative of the whole ecosystem.
Birds may eat the trapped organisms.
Some some animals may eat others or escape.
What are ways to fix the errors in a pitfall trap?
Traps should be placed randomly and many traps should be set up.
Cover the pitfall trap with a lid.
Check the traps regularly.
Why do we take samples?
Can’t count all the plants and animals in an ecosystem so instead samples that will represent the whole ecosystem are taken.
What do samples need to be?
Random
Repeated several times
Use the same technique
What is a biotic factor?
A biotic factors are all the factor that affect a species due to activities of living things.
What is an abiotic factor?
abiotic factors are non=living factor which affect a species.
What is a light meter used for?
How does it work?
Used to measure light intensity in desired area.
Light sensitive panel captures light intensity and measures it on a lux scale.
When using a light meter ensure?
It is held steady
No persons shadow is over light panel
Cloud cover is similar for each measurement
Take measurements at the same time of day
What is a moisture meter used for?
How is it used.
Used to measure the moisture content of the soil.
A stick is inserted into ground to make a hole then probe is inserted into soil gently so as not to bend or break it.
When using moisture meter ensure?
Dry probe between each sample
Place a mark around the probe to ensure it is inserted to the same depth.
What is a pH meter used for?
How is it used?
Used to measure how acidic or alkaline the soil is.
A stick is inserted into ground to make a hole then probe is inserted into soil gently so as not to bend or break it.
When using a pH meter ensure?
Clean probe between each sample
Place mark around the probe to ensure it is inserted to the same depth.
What is a thermometer used for?
How is it used?
Used to measure the temperature of the soil or water.
The same way as a pH probe.
When using a thermometer ensure?
Place mark around the thermometer to ensure it is inserted to the same depth.
Ensure the thermometer has adequate time to reach temperature of soil.
What is a transept line?
A transect line is a line set up to investigate the effect of an abiotic factor on the distribution of an organism. i.e. the effect of light intensity on the distribution of daisies.
Biodiversity in an ecosystem can be affected by?
Biotic factors and abiotic factors. These factors either increase or decrease the biodiversity of an ecosystem.
What are some biotic factors?
Competition for resources Disease Food availability Grazing Predation
What are some abiotic factors?
Light intensity
Moisture
pH
Temperature
What do scientists use to identify organisms?
Scientists use keys to make it easier to identify organisms that are sampled.
What two types of keys are there?
Branched keys and paired statement keys.
What is an indicator species?
Indicators species are species that by their presence of absence, indicate environmental quality/ levels of pollution.
What are in plant cells?
Cell membranes Cytoplasm Nucleus Chloroplast Vacuol Cell wall
What are green plants able to do that animals can’t do?
Green plants can make their own food using light energy from the sun. This process is called photosynthesis.
What are green plants called?
Green plants are called producers.
What can producers do?
Producers are the only organisms capable of making their own food in the form of carbohydrates.
What are carbohydrates?
Carbohydrates are molecules containing carbon, hydrogen and oxygen which are made during photosynthesis.
What do plants need?
Plants need carbon dioxide, water, light energy and chlorophyll
What do plants make?
Plants produce oxygen and sugar (glucose).
What is the equation for photosynthesis?
Carbon + water —> sugar + oxygen
Dioxide (Light)
(Chlorophyll)
Carbon dioxide and water are?
Light and chlorophyll
Sugar and oxygen.
Raw materials.
Essential requirements
Products.
What two stages does photosynthesis occur in?
Stage 1= light reactions
(Light dependent stage)
Stage 2= carbon fixation
(Temperature dependent stage)
Why is stage 1 know as the light dependent stage?
Stage 1 uses light energy from the sun to split water molecules into hydrogen and oxygen.
Stage one is know as photolysis: photo Lysis
Light to split
What happens in stage 1?
Light energy from the sun is trapped by chlorophyll in the chloroplasts and is converted into chemical energy.
This energy is used to generate ATP.
What does stage one do to the ATP?
Stage one produces one molecule of ATP which is used in stage 2.
Which raw material is used during stage 1?
Water.
Where does the water from photosynthesis come from?
Water is found in the soil.
How does the water get into the plant?
Water is obtained by osmosis through the roots of the plant.
Which product is produced during stage one?
Oxygen and it diffuses from the cell. The hydrogen from the water is used in the second stage.
Stage one reaction?
Light energy is trapped by chlorophyll —> water —> chemical energy (ATP) —> passes second stage
(water—>) Hydrogen —> transported to second stage
(Water—>) Oxygen —> diffuses out of chloroplast
What happens to these three things during photolysis:
Oxygen
Hydrogen
ATP?
Oxygen- excess diffuses out of leaf
Hydrogen- transported to stage 2
ATP- used for energy in stage 2
Why is carbon fixation know as the temperature dependent stage?
Carbon fixation is a series of enzymes controlled reactions.
Enzymes require an optimum temperature to work best.
It takes place in the chloroplasts.
Carbon fixation is also called?
The Calvin cycle
Light independent stage
Temperature dependent stage
Which raw material is used during carbon fixation?
Carbon dioxide.
Where does the carbon dioxide for photosynthesis come from?
Carbon dioxide is found in the air all around us.
How does the carbon dioxide get into the plant?
Carbon dioxide is obtained by diffusion through the tiny pores in the leaf surface.
Which product is produced during carbon fixation?
Sugar.
What products from stage one are need in stage 2?
Hydrogen and ATP are needed from stage one.
What do hydrogen and carbon dioxide do?
Hydrogen and carbon dioxide combine using energy provided by ATP made in stage 1 to produce sugar.
What two things can sugar be converted to?
Starch and cellulose.
What can the chemical energy in sugar do?
Is available for respiration or can be used to store starch or be made into cellulose from structural support.
What is starch?
Starch is a storage molecule.
What is cellulose?
Cellulose is a structural molecule used to build cells walls.
What is a limiting factor?
A limiting factor is something which is in short supply that prevents photosynthesis occurring at its maximum rate.