Ecology And Biodiversity Flashcards
Ecosystem
An ecosystem is the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.
How do organisms and survive and reproduce?
To survive and reproduce, organisms require a supply of materials from their surroundings and from the other living organisms there.
How do plats act in a community or habitat
Plants in a community or habitat often compete with each other for light and space, and for water and mineral ions from the soil. Animals often compete with each other for food, mates and territory.
What is interdependence
Within a community each species depends on other species for food, shelter, pollination, seed dispersal etc.
What is a stable community
one where all the species and environmental factors are in balance so that population sizes remain fairly constant.
Abitic (non-living) factors which can affect a community
light intensity
• temperature
• moisture levels
• soil pH and mineral content
• wind intensity and direction
• carbon dioxide levels for plants
• oxygen levels for aquatic animals.
Biotic (living) factors which can affect a community are
• availability of food
• new predators arriving
• new pathogens
• one species outcompeting another so the numbers are no
longer sufficient to breed.
Examples of organism adaptations
Some organisms live in environments that are very extreme, such as at high temperature, pressure, or salt concentration. These organisms are called extremophiles. Bacteria living in deep sea vents are extremophiles.
Why do organisms have adaptations
Organisms have features (adaptations) that enable them to survive in the conditions in which they normally live. These adaptations may be structural, behavioural or functional.
What are photosynthetic organisms
the producers of biomass for life on Earth.
Feeding relationships
Represented by food chains. All food chains begin with a producer which synthesises molecules. This is usually a green plant or alga which makes glucose by photosynthesis.
Food chain
Producers are eaten by primary consumers, which in turn may be eaten by secondary consumers and then tertiary consumers.
Predators and prey
Consumers that kill and eat other animals are predators, and those eaten are prey. In a stable community the numbers of predators and prey rise and fall in cycles.
The carbon cycle
The carbon cycle returns carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis.
Water cycle
The water cycle provides fresh water for plants and animals on land before draining into the seas. Water is continuously evaporated and precipitated.
Role of microorganisms in cycling materials
through an ecosystem by returning carbon to the atmosphere as carbon dioxide and mineral ions to the soil.
Biodiversity
Biodiversity is the variety of all the different species of organisms on earth, or within an ecosystem.
What does a great biodiversity do
A great biodiversity ensures the stability of ecosystems by reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment.
Why is biodiversity important
The future of the human species on Earth relies on us maintaining a good level of biodiversity. Many human activities are reducing biodiversity and only recently have measures been taken to try to stop this reduction.
Why is pollution increasing
Rapid growth in the human population and an increase in the standard of living mean that increasingly more resources are used and more waste is produced. Unless waste and chemical materials are properly handled, more pollution will be caused.
How can pollution occur
Pollution can occur:
• in water, from sewage, fertiliser or toxic chemicals
• in air, from smoke and acidic gases
• on land, from landfill and from toxic chemicals.
Pollution kills plants and animals which can reduce biodiversity.
Land use
Humans reduce the amount of land available for other animals and plants by building, quarrying, farming and dumping waste.
Effects of destruction of peat bogs
The destruction of peat bogs, and other areas of peat to produce garden compost, reduces the area of this habitat and thus the variety of different plant, animal and microorganism species that live there (biodiversity).
The decay or burning of the peat releases carbon dioxide into the atmosphere.
Why does deforestation happen
• provide land for cattle and rice fields
• grow crops for biofuels
What contribted to global warming
Levels of carbon dioxide and methane in the atmosphere are increasing, and contribute to ‘global warming’.
How can we reduce negative effects of hukans on ecosystems and biodiversity
• breeding programmes for endangered species
• protection and regeneration of rare habitats
• reintroduction of field margins and hedgerows in agricultural
areas where farmers grow only one type of crop
• reduction of deforestation and carbon dioxide emissions by
some governments
• recycling resources rather than dumping waste in landfill.
