B16/17 Flashcards
What is biodiversity
Biodiversity is the variety of all the different species of organisms on earth, or within an ecosystem
What does a greater biodiversity mean
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 it important to maintaining a large biodiversity
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 are more resources used and why can this be a problem
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
- in water, from sewage, fertiliser or toxic chemicals
- in air, from smoke and acidic gases
- on land, from landfill and from toxic chemicals
How does pollution affect biodiversity
Pollution kills plants and animals which can reduce biodiversity
How do humans affect the land around them
Humans reduce the amount of land available for other animals and plants by building, quarrying, farming and dumping waste
What does the destruction of peat bogs mean
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)
What does the decay of burning peat release
Carbon dioxide into the atmosphere
What is global warming
Levels of carbon dioxide and methane in the atmosphere are increasing, and contribute to ‘global warming’.
How do people maintain 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
What are producers
Producers are mostly plants and algae which transfer about 1 % of the incident energy from light for photosynthesis
How much energy is transferred from each trophic level and how is energy lost
Only approximately 10 % of the biomass from each trophic level is transferred to the level above it
• not all the ingested material is absorbed, some is egested as faeces
• some absorbed material is lost as waste, such as carbon dioxide and water in respiration and water and urea in urine
Large amounts of glucose are used in respiration
What is food security
Food security is having enough food to feed a population.
What are biological factors which are threatening food security
- the increasing birth rate has threatened food security in some countries
- changing diets in developed countries means scarce food resources are transported around the world
- new pests and pathogens that affect farming
- environmental changes that affect food production, such as widespread famine occurring in some countries if rains fail
- the cost of agricultural inputs
- conflicts that have arisen in some parts of the world which affect the availability of water or food
How can food be used to feed people on earth
Sustainable methods must be found to feed all people on Earth
How can the efficiency of food production be improved
Restricting energy transfer from food animals to the environment.
This can be done by limiting their movement and by controlling the temperature of their surroundings
Some animals are fed high protein foods to increase growth
What is an ecosystem
An ecosystem is the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment
What do organisms need to survive
To survive and reproduce, organisms require a supply of materials from their surroundings and from the other living organisms there.
How do plants compete with eachother
Plants in a community or habitat often compete with each other for light and space, and for water and mineral ions from the soil.
How do animals compete with eachother
Animals often compete with each other for food, mates and territory
What is interdependance 🗿🗿
Within a community each species depends on other species for food, shelter, pollination, seed dispersal etc. If one species is removed it can affect the whole community
What is a stable community
A stable community is one where all the species and environmental factors are in balance so that population sizes remain fairly constant
What are examples of abiotic factors in a community (7)
- light intensity
- temperature
- moisture levels
- soil pH and mineral content
- wind intensity and direction
- carbon dioxide levels for plants
- oxygen levels for aquatic animals
What are biotic factors (4)
- availability of food
- new predators arriving
- new pathogens
- one species outcompeting another so the numbers are no longer sufficient to breed
What do all food chains begin with
Producers
Usually a green plant or algae that make glucose from photosynthesis
How does a food chain work
Producers are eaten by primary consumers, which in turn may be eaten by secondary consumers and then tertiary consumers.
What are predators and prey and how do they interact
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
How are materials cycled
Many different materials cycle through the abiotic and biotic components of an ecosystem
Why are materials cycled
All materials in the living world are recycled to provide the building blocks for future organisms
What does the carbon cycle do
The carbon cycle returns carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis
What does the water cycle fo
The water cycle provides fresh water for plants and animals on land before draining into the seas.
Water is continuously evaporated and precipitated
How do microorganisms cycle nutrients
microorganisms cycle materials through an ecosystem by returning carbon to the atmosphere as carbon dioxide and mineral ions to the soil
What are the ideal conditions for decay
Warm temperatures
Wet
Lots of oxygen
How do farmers make compost and how is it used
Gardeners and farmers try to provide optimum conditions for rapid decay of waste biological material.
The compost produced is used as a natural fertiliser for growing garden plants or crops
What does anaerobic decay produce and how can this be used
Anaerobic decay produces methane gas.
Biogas generators can be used to produce methane gas as a fuel
Equation to find population size
Total area/ area sampled x number of organisms of that species counted in sample
