Topic 7 - Ecology Flashcards
What is an ecosystem?
The interaction of a community of living organisms (biotic) with the nonliving (abiotic) parts of their environment
Define biotic
Living organisms
Define abiotic
Nonliving
What do organisms require in order to survive and reproduce?
Supply of materials from their surroundings and from the other living organisms there
What do plants in a community or habitat often compete for?
Light and space, water and mineral ions from the soil
What do animals in a community or habitat often compete for?
Food, mates and territory
Within a community what does each species depend on another species for?
Food, shelter, pollination and seed dispersal
What is interdependence?
If one species is removed from a community, it can affect the whole community
What is a stable community?
Where all the species and environmental factors are in balance so that population sizes remain fairly constant
What are the abiotic 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
What are the biotic factors that can affect a community?
- food availability
- new predators
- new pathogens
- one species outcompeting another so the numbers are no longer sufficient to breed
What are adaptations?
Features that allow organisms to survive in the conditions which the normally live
What are the three types of adaptation?
- structural
- behavioural
- functional
Give examples of extreme environments.
- high temperature
- high pressure
- high salt concentration
What are extremophiles?
Organisms that live in extreme environments
Give an example of an extremophile.
Bacteria living in deep sea vents
How can feeding relationships within a community be shown?
Food chains
What do all food chains start with?
A producer which synthesises molecules - usually a green plant or alga which makes glucose by photosynthesis
What are experimental methods using transects and quadrants used for?
Used by ecologists to determine the distribution and abundance of species in an ecosystem
What are producers eaten by?
Primary consumers
What are primary consumers eaten by?
Secondary consumers
What are secondary consumers eaten by?
Tertiary consumers
What is a predator?
Consumers that kill and eat other animals
What is prey?
Animals that are eaten by predators
What happens to the numbers of predators and prey in a stable community?
They rise and fall in cycles
Why are all materials in the living world recycled?
To provide building blocks for future organisms
What does the carbon cycle do?
It returns carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis
What does the water cycle do?
It provides freshwater for plants and animals on land before draining it into the seas through continuous evaporation and precipitation
What affects the rate of decay?
Temperature, water and availability of oxygen
What do you gardeners and farmers try to provide optimum conditions for?
Rapid decay of waste biological material
What is the compost produced by decay used for?
And natural fertiliser for growing garden plants or crops
What does anaerobic decay produce?
Anaerobic decay produces methane gas
What can be used to produce methane gas as a fuel?
Biogas generators
How does temperature affect the rate of decay?
Warmer temperatures make things decompose quicker because they increased the rate that the enzymes involved in decomposition work at
How does oxygen availability affect the rate of decay?
Many organisms need oxygen to respire which they need to do to survive but the micro organisms involved in anaerobic decay don’t need oxygen
How does water availability affect the rate of decay?
Decay takes place faster in moist environment because the organisms involved in decay need water to carry out biological processes
What are the environmental changes that affect the distribution of species in an ecosystem?
Temperature, availability of water and composition of atmospheric gases
What are the three types of environmental changes that affect the distribution of species in an ecosystem?
Seasonal, geographic or caused by human interaction
What is biodiversity?
Variety of all the different species of organisms on Earth or within an ecosystem
How does a good biodiversity ensure the stability of ecosystems?
By reducing the dependence of one species or another for food, shelter and the maintenance of the physical environment
What does the future of the human species on earth rely on?
Us maintaining a good level of biodiversity, as many human activities are reducing biodiversity and only recently measures have been taken to try to stop this reduction
What has rapid growth in the human population and an increase in the standard of living lead to?
Increasingly more resources are used and more waste is produced
Unless waste and chemical materials are properly handled, what will happen?
More pollution will be caused
Where can pollution occur?
Water, air or land
How is pollution created in water?
From sewage, fertiliser or toxic chemicals
What pollution is in the air?
From smoke and acidic gases
What causes pollution on land?
From landfill and from toxic chemicals
How does pollution affect living organisms?
Pollution kills plants and animals which can reduce biodiversity
How do humans reduce the amount of land available for other animals and plants?
By building, quarrying, farming and dumping waste
What reduces the area of the habitat?
The destruction of peat bogs, and other areas of peat to produce garden compost
What does reducing the area of a habitat also reduce?
The variety of different plant, animal and microorganisms species that live there (by diversity)
What does the decay or burning of peat release?
Carbon dioxide into the atmosphere
What has large-scale deforestation in tropical areas occurred for?
- To provide land for cattle and ricefields
- to grow crops for biofuels
What contributes to global warming?
Levels of carbon dioxide and methane in the atmosphere are increasing
What are the biological consequences of global warming?
- Higher temperatures causing ice to melt and flooding
- change to the distribution of wild animal and plant species as temperature changes
- changes in migration patterns
- biodiversity could be reduced
What have scientists and concerned citizens put programs in place for?
To reduce the negative effects of humans on ecosystems and biodiversity
What are the programs that scientists and concerned citizens have put in place to reduce the negative affects of humans on ecosystems and biodiversity?
- breeding programs 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
How can trophic levels be represented?
By numbers starting at level one with plants and algae
How are further trophic levels numbered?
Subsequently according to how far the organism is along the food chain
What is trophic level 1?
Plants and algae make their own food and are called producers
What is trophic level two?
Herbivores eat plants or algae and are called primary consumers
What is trophic level three?
Carnivores that eat herbivores are called secondary consumers
What is trophic level four?
Carnivores that eat other carnivores are called tertiary consumers
What is apex predator?
Carnivores with no predators
What do decomposes do?
Decomposers break down dead plant and animal matter by secreting enzymes into the environment, small soluble food molecules then diffuse into the microorganism
What are pyramids of biomass?
They are diagrams that are constructed to represent the relative amount of biomass in each level of a food chain
What is the bottom level of a pyramid of biomass?
Trophic level one
How much energy does a producer transfer to the primary consumer?
About 1% of the incident energy from light for photosynthesis
How much of the biomass from each trophic level is transferred to the level above it?
About 10%
What are losses of biomass due to?
- 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
What is used in large amounts during respiration?
Large amounts of glucose are used in respiration
How do you calculate efficiency of biomass transfer?
Efficiency = biomass transferred to next level / biomass available at previous level x 100
What is food security?
Having enough food to feed a population
What are the biological factors that are threatening food security?
- The increasing birthrate
- changing diet in developed countries mean 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
- The cost of agricultural inputs
- conflicts that have arisen in some parts of the world which affect the availability of food or water
What must be done in order to feed all people on earth?
Sustainable methods must be found
How can the efficiency of food production be improved?
By restricting energy transfer from food animals to the environment
How do you restrict energy transfer from food animals to the environment?
By limiting their movement and controlling the temperature of their surroundings
Why are some animals fed high-protein foods?
To increase growth
Why is it important to maintain fish stocks at a level where breeding continues?
Fish stocks in the oceans are declining and certain species may disappear altogether in some areas
How do we conserve fish stocks at a sustainable level?
Controlling the sizes of nets and introducing fishing quotas
What do modern biotechnology techniques enable?
Large quantities of microorganisms to be cultured for food
What is the fungus fusarium useful for?
Producing micro protein, a protein rich food suitable for vegetarians
How is the fungus fusarium grown?
On glucose syrup, in aerobic conditions, and the biomass is harvested and purified
How is genetic modification a good biotechnology technique?
A genetically modified bacteria produces human insulin, which when harvested and purified it is useful to treat people with diabetes
What can GM crops provide?
More food or food with an improved nutritional value such as golden rice
