CB9 Flashcards
Define ‘Ecology’
The study of organisms and their interaction with the environment.
Define ‘Ecosystem’
A biological community of interacting organisms and their physical environment.
Define ‘Community’
All the biotic factors in an ecosystem.
Define ‘Population’
All the organisms of one species in an ecosystem.
Define ‘Interdependence’
The idea that all the biotic factors in an environment are linked in some way.
Define ‘Habitat’
The physical space a population or community occupy in an ecosystem.
Define ‘Abundance’
A measure of how common something is in an area.
Define ‘Quadrat’
A fixed area from which a sample is taken.
Define ‘Biotic’
Living.
Define ‘Abiotic’
Non-living.
What is the equation for population size?
Population size = Number of organisms in all quadrats x (Total size of area where organism lives / Total area of quadrats)
What does a food web show?
It shows the feeding relationships between the organisms in a community.
What is the distribution of organisms?
The distribution of organisms is where they are found in an ecosystem.
What factors can affect distribution?
Distribution can be affected by physical and chemical factors, such as temperature, rainfall and substances in the soil.
What are abiotic factors?
Non-living factors that can influence where plants or animals live (e.g. temperature, the amount of light)
What is a belt transect?
A line in an environment along which samples are taken to measure the effect of abiotic factors on the distribution of organisms.
How is an area measured (belt transect)?
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 do changes in abundance in areas along the habitat show?
Changes in abundance can show which abiotic factor has the greatest effect on the organisms.
What varies in the same species of organisms in different environments?
Each species of organisms has certain adaptations that mean an organism is suited to particular conditions. If abiotic factors change, then the distribution of organisms may also change.
What are pollutants?
Substances that cause harm in the environment. They cause pollution and harm other organisms.
What are biotic factors?
Biotic factors are the organisms living in an ecosystem that affect other living organisms.
What is the predator-prey cycle?
The regular variation in numbers of predators and numbers of prey within a feeding relationship.
What is biodiversity?
The variety of species in an area.
Is the increase of biodiversity a good thing?
Yes, the increase of biodiversity is good.
What is a parasitic relationship?
A feeding relationship in which a parasite benefits and its host is harmed.
What is a mutualistic relationship?
A relationship between individuals of different species where both individuals benefit.
Give an example of a parasitic relationship?
Tapeworms, lice etc.
Give an example of a mutualistic relationship?
A sea anemone and clownfish, Single-celled algae and coral polyps.
How are tapeworms adapted for their parasitic relationship?
Tapeworms live inside the intestine of organisms and are adapted by the following:
1. They have hooks and suckers attached to the worms head so that the worm can attach its head firmly on the hosts intestinal wall.
2. It has a flattened body which allows absorption of nutrients over whole surface without the need for a digestive system or circulatory system
3 It has segments that contain male and female sex organs so fertilization can occur
How do sea anemone and clownfish help each other in their mutualistic relationship?
The sea anemone and clownfish have a mutualistic relationship. A sea anemone’s stinging tentacles protect clownfish from predators and clownfish provide nutrients in their feces which help the anemone grow.
What is fish farming?
A method of fishing. It works by growing fish in a contained area, usually to supply humans with food. It aims to produce more fish and so reduce overfishing of wild fish.
What is overfishing?
Overfishing is taking more fish from a population than are replaced by the fish reproducing so that the population of fish falls over time.
What effects does overfishing have on the environment and biodiversity?
- Overfishing of wild fish stocks has damaged some aquatic (water) ecosystems
- Fish farming causes problems because so many fish are being kept in a small space. Uneaten food, and faeces from the fish, sinks to the bottom of the water. This can change conditions, which may harm the wild organisms that live there.
Why are new species introduced to ecosystems?
Some species are introduced in order to affect an ecosystem, such as to reduce the numbers of another species that has gotten out of control. This often happens after humans have changed ecosystems and affected the food web.
What is Eutrophication?
Eutrophication is the addition of more nutrients to an ecosystem than it normally has. This can also harm an ecosystem, causing a form of pollution.
How can Eutrophication harm an aquatic ecosystem (STEPS)?
- Fertiliser is added
2a. Heavy rain washes fertiliser off
2b. Nitrates and phosphates dissolve in soil water - Nitrates and phosphates not taken in by plants are washed into stream or river
- High nitrate and phosphate concentrations in the water encourage plants and algae to grow rapidly
- Surface plants block sunlight, so plants in the water die and stop producing oxygen through photosynthesis
- Bacteria that breaks down dead materials increase in numbers and use up more oxygen from the water
- The oxygen concentration of the water decreases
- Aquatic animals such as fish die due to lack of oxygen.
What is reforestation?
Reforestation is planting new forests where old forests have been cut down.
What is conservation?
Conservation is when an effort is made to protect a rare or endangered species or habitat.
How can conservation of a species be made easier?
It can be easier if the species habitat is also protected.
How are humans helping tiger numbers increase?
Humans are breeding tigers in captivity to increase their numbers.
Why is preserving biodiversity important?
Preserving biodiversity is important for:
1. Conserving individual species or communities
2. Making sure areas can recover faster from natural disasters such as floods (areas with greater biodiversity recover faster)
3. Humans need a variety of animals for their own use (e.g. eating)
Describe the water cycle (STEPS)?
- Water evaporates from oceans, lakes and rivers to form water vapour
- As air rises, it cools, so water vapour in it condenses to form clouds
- As water droplets get too large and heavy, they fall as rain or snow
- Rain falls down either into rivers or into the ground to become ground water
- Rivers flow into lakes and eventually the water returns to the ocean
How can water be made potable (safe for drinking)?
To make it potable, the water must be treated with chemicals and filtered, to remove dirt, pathogens and any toxic substances.
How can water be collected in areas experiencing droughts?
In areas where there is drought, drinking water must either be collected from air or extracted from sea water.
What is desalination?
It is a process that produces fresh drinking water by separating the water from the salts in salty water.
What is the carbon cycle?
It is a sequence of processes by which carbon moves from the atmosphere, through living and dead organisms, into sediments and into the atmosphere again.
Describe how carbon is cycled through the ecosystem?
- (PLANTS) Carbon dioxide molecules in the atmosphere diffuse into plant leaves. Inside a leaf, photosynthesis may cause the carbon atom in the molecule to become part of another carbon compound, called glucose. If glucose is used by the plant for respiration, the carbon atoms will become part of carbon dioxide again and be released back into the atmosphere. Alternatively, the glucose may be changed into other carbon compounds and used to make more plant biomass.
- (ANIMALS) Carbohydrates, fats and proteins in plants all contain carbon atoms. When an animal eats a plant, some of these compounds are digested and taken into the body. The rest will leave the animal’s body in faeces. Some of the absorbed carbon compounds are used for respiration and some form waste products that are excreted in urine. The rest are used to build more complex compounds in the animal’s tissue, making more animal biomass. If the animal is eaten by a predator, the same process happens again.
What is the role of decomposers in the carbon system?
Dead organisms are broken down into smaller pieces by the process of decay. Organisms such as earthworms are involved in this process. Decomposition is the process by which bacteria and fungi break dead organisms into their simple compounds . Plants can absorb and use these compounds again, completing the cycle.
What are decomposers?
An organism that feeds on dead material, causing decay (e.g. fungi, bacteria)
What happens to buried plants if decomposers can’t reach them?
If many large dead plants are buried so quickly that decomposers cannot feed on them, then over millions of years they may be changed into peat or coal by heat and pressure from the earth. This can then create fossil fuels which when combusted, create carbon dioxide in the air for the carbon cycle to repeat itself again.
Where do plants contain nitrogen?
Plants contain nitrogen compounds in proteins and DNA.
Why do plants need nitrogen?
Plants need nitrogen to grow well. Nitrogen assists plants with its growth and a deficiency of nitrogen will mean a plant with much less growth.
Where do plants get their nitrogen from?
Plants cannot use unreactive nitrogen from the air. Instead they absorb nitrogen compounds such as nitrates that are dissolved in soil water.
What is nitrogen-fixing bacteria?
Bacteria that can take nitrogen from the atmosphere and convert it into more complex nitrogen compounds such as ammonia.
What is the nitrogen cycle (STEPS)?
Why is nitrogen-fixing bacteria good for the soil?
Some plants such as peas and beans have a mutualistic relationship with these bacteria. The bacteria are protected inside the nodules in the plant roots, and the plant gets nitrogen compounds directly from the bacteria.
Describe a diagram of the carbon cycle?
Where is nitrogen found in the human body?
Nitrogen are vital for the formation of Amino Acids.
