P2- Ecology Flashcards
What is an ecosystem?
The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment
What is a habitat?
The place where an organism lives
What is a population?
All the members of a single species living within a geographical area
What is a community?
All of the different organisms living in a habitat
What is a species?
A type of organism that is the basic unit of classification
What is an organism?
A living thing (animal, plant, bacteria)
What is competition?
-Plants and animals have to compete for limited resources
-The best adapted plants and animals survive and win
What do organisms require in order to survive and reproduce?
A supply of materials from their surroundings and from the other living organisms there
4 things plants have to compete for
-Light
-Space
-Water
-Mineral ions
3 things animals have to compete for
-Food
-Mates
-Territory
What is interdependence?
-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 community where all the species and environmental factors are in balance so that population sizes remain fairly constant
What are abiotic factors?
Non living factors of the environment
7 examples of abiotic factors
-Temperature
-Light intensity
-Moisture levels
-Soil pH and mineral content
-Wind intensity and direction
-Carbon dioxide levels (for plants)
-Oxygen levels (for aquatic animals)
How can abiotic factors affect the size of populations in a community?
-A change in environment could be an increase or decrease in an abiotic factor
-These changes affect the size of population
-This means they can also affect the population sizes of other organisms that depend on them
What are biotic factors?
Living factors of the environment
5 examples of biotic factors
-Availability of food
-New predators arriving
-New pathogens
-One species out competing another (numbers are no longer sufficient to breed)
How can biotic factors affect the size of populations in a community?
-A change in environment could be the introduction of a new biotic factor
-These changes can affect the size of populations in a community
-This can have knock-on effects because of interdependence
What do organisms have that enable them to survive in the conditions they normally live in?
Adaptations/Features
3 types of adaptations
-Structural
-Behavioural
-Functional
What is structural adaptation?
Features of an organism’s body structure
Examples of structural adaptation
-Coloured fur (camouflage)
-Thick/thin layer of fat (retain/lose heat)
-Sharp teeth and claws (animals)
-Spikes (plants)
What is behavioural adaptation?
Ways that organisms behave
Examples of behavioural adaptation
-Animals working in a pack to hunt
-Plants shoot grows quickly towards the sun (photosynthesis)
-Migrating to warmer climates during the winter
What is functional adaptation?
Things that go on inside an organism’s body that can be related to processes like reproduction and metabolism
Examples of functional adaptation
-Snakes venom (animals)
-Nettle poisons (plants)
-Desert animals conserve water (produce little sweat)
-Brown bears hibernate in winter, lower metabolism to conserve energy
Adaptations of a polar bear
-Thick coat and layer of fat (warmth)
-Greasy fur (waterproof)
-White fur (camo)
-Strong swimmers (prey)
-Big feet (spread out on surface)
Adaptations of a camel
-Long eyelashes (protect from sand)
-Hump (stores fat)
-Large, flat feet (stop slipping on sand, protect from heat)
-Sand coloured (camo)
-Short fur
What are extremophiles?
Organisms adapted to live in very extreme conditions
Examples of extreme environments
-High temperature
-High pressure
-High salt concentration
An example of an extremophile
Bacteria living in deep sea vents
What are photosynthetic organisms?
The producers of biomass for life on earth
What do food chains show?
-The feeding relationships within a community
-What is eaten by what in an ecosystem
What do the arrows in a food chain mean?
Transfers of energy
What do all food chains begin with?
A producer which synthesis molecules
An example of a producer that begins the food chain
A green plant or algae which makes glucose by photosynthesis
What are producers eaten by?
Primary consumers
What are primary consumers eaten by?
Secondary consumers
What are secondary consumers eaten by?
Tertiary consumers
Simple example of a food chain
Leaf -> Caterpillar -> Bird -> Cat
What are predators?
Consumers (animals/mammals) that hunt for prey
What are prey?
An animal that is hunted down and eaten by a predator
What is an apex predator?
The highest predator that cannot be killed/ eaten
What happens in a stable community containing predators and prey?
The number of predators and prey rise and fall in cycles
If the population of prey increases, what happens to the population of predators?
They increase
If the population of predators increases, what happens to the population of prey?
They decrease
What is a quadrat?
A square frame enclosing a known area
What is the aim of the quadrat practical?
-Measure the population size of a common species in a habitat
-Use sampling techniques to investigate the effect of a factor on the distribution of this species.
Why are materials in the living world recycled?
To provide the building blocks for future organisms
How does the Water Cycle work (5 steps)?
1) Energy from the sun makes water evaporate from the land and sea turning it into water vapour
2) Water evaporates from plants (transpiration)
3) The warm water vapour is carried upwards (as warm air rises). When it gets higher up, it cools and condenses to form clouds
4) Water falls from the clouds as precipitation onto land to provide fresh water for plants and animals
5) It then drains into the sea and the process starts again
How does the Carbon cycle work?
1) CO2, removed from the atmosphere by green plants and algae during photosynthesis
2) Carbon makes glucose turned into carbs, fats and proteins that make up the bodies of plants and algae
3) Plants and algae respire, some carbon returns to the atmosphere as CO2
4) When plants and algae are eaten by animals, some carbon becomes part of the fats and protein in their bodies. Carbon them moves through the food chain.
5) Carbon returns to the atmosphere as CO2 when animal respire
6) Organisms feed on the remains of dead plants and animals. Organisms respire and CO2 returns to the atmosphere
7) Animals produce waste broken down by microorganisms
8) Combustion of wood and fossil fuels releases CO2 back into air
What microorganisms are involved in cycling materials through an ecosystem?
-Bacteria
-Fungi
How is carbon returned to the atmosphere?
-Decomposers (bacteria/fungi) break down organic matter
-Carbon is released as CO₂ through respiration by microorganisms during decomposition
-This CO₂ returns to the atmosphere, which is then used by plants in photosynthesis
How are mineral ions returned to the soil?
-Microorganisms decompose dead matter, releasing mineral ions like nitrogen, phosphorus, and potassium back into the soil
-These minerals are vital for plant growth and are used by plants to produce proteins and other compounds
What is decomposition?
The breakdown of dead matter (plants, animals etc)
3 factors that affect the rate of decay of biological material
1) Temperature
2) Oxygen availability
3) Water availability
How does temperature affect the rate of decay of biological material?
-Warmer temperatures make things decompose quicker as they increase the rate that enzymes work
-However, if its too hot, the enzyme will denature so decomposition will slow down
How does oxygen availability affect the rate of decay of biological material?
Many organisms need oxygen to respire which they need to survive
How does water availability affect the rate of decay of biological material?
Decay takes place faster in moist environments because the organisms involved in decay need water to carry out biological processes
What do gardeners and farmers do for rapid decay of waste biological material?
Try and provide the optimum conditions of temperature, water and oxygen availability
What is compost and what is it used for?
-Decomposed organic matter
-Used as a natural fertiliser for crops and garden plants
What does anaerobic decay produce?
Methane gas
How is biogas made?
By anaerobic decay of waste material
Where is biogas made?
In a simple fermenter called a digester or generator
Why do biogas generators need to be kept at a constant temperature?
To keep the microorganisms respiring away
What can biogas generators be used to produce?
Methane gas as a fuel
2 main types of biogas generators
-Batch generators
-Continous generators
What is the aim of the decay pratical (RP 10)?
To investigate the effect of temperature on the rate of decay of fresh milk by measuring pH change
What can environmental changes cause?
The distribution of organisms to change
3 examples of environmental changes that can affect where an organism lives
1) Change in the availability of water
2) Change in temperature
3) Change in the composition of atmospheric gases
What is Biodiversity?
The variety of all the different species of organisms on earth, or within an ecosystem
What does a great biodiversity ensure?
The stability of ecosystems
Why does biodiversity ensure the stability of ecosystems?
By reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment
What does the future of human species on earth rely on?
Us maintaining a good level of biodiversity
What is reducing biodiversity?
Human activities
2 things that mean increasingly more resources are used and more waste is produced?
1) Rapid growth in the human population
2) Increase in the standard of living
3 ways pollution occurs
1) in water (from sewage, fertiliser or toxic chemicals)
2) in air (from smoke and acidic gases)
3) on land (from landfill and from toxic chemicals)
How is pollution reducing biodiversity?
By killing animals and plants
4 ways humans are reducing the amount of land available for other animals and plants
1) Building
2) Quarrying
3) Farming
4) Dumping waste
What does the destruction of peat bogs produce?
Garden compost
What is the effect of destroying peat bogs?
It reduces the area of the habitat and thus the variety of different plant, animal and microorganism species that live there (biodiversity)
What does the decay or burning of the peat release?
Carbon dioxide into the atmosphere
2 reasons why large scale deforestation has occurred
1) To provide land for cattle and rice fields
2) To grow crops for biofuels
What is contributing to global warming?
The levels of carbon dioxide and methane in the atmosphere increasing
List some biological impacts of global warming
-Polar ice caps melting
-Sea levels rising
-Unusual weather patterns
-Extinction of species
5 ways scientists are trying to 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 CO2 emissions by governments
-Recycling resources rather than dumping waste in landfill
4 conflicting pressures that are affecting how biodiversity is maintained
1) Cost of protecting biodiveristy
2) Affect people’s livelihoods (lose jobs, affect local economy)
3) Conflict between protecting biodiversity or food security
4) Affect the environment
What are Trophic levels?
The different stages of a food chain which consist of one or more organisms that perform a specific role in the food chain
How are Trophic levels represented?
Numbers
After the first trophic level how are further trophic levels numbered?
Numbered subsequently according to how far the organisms are along the food chain
Level 1 of the trophic level
-Plants and algae make their own food
-Called producers
Level 2 of the trophic level
-Herbivores eat plants/algae
-Called primary consumers
Level 3 of the trophic level
-Carnivores that eat herbivores
-Called secondary consumers
Level 4 of the trophic level
-Carnivores that eat other carnivores
-Called tertiary consumers
What do decomposers do?
-Break down dead plant and animal matter by secreting enzymes into the environment
-Small soluble food molecules then diffuse into the microorganism
What is biomass?
The dry mass of living materials at each stage in the food chain
How do you calculate the efficiency of biomass transfer?
efficiency= (energy transferred to next level /total energy available at previous level) x100
Does Level 1 or Level 4 of the trophic levels have the most mass?
Level 1 (Plants and algae)
If an oak tree had a biomass of 500,000, an aphid of 1,000 and a ladybird of 50 what would be their pyramid of biomass?
Ladybird
Aphid
Oak tree
If there was 1 number of oak tree, 10,000 aphids and 200 ladybirds what would the pyramid of number be?
Ladybird (middle size)
Aphid (widest)
Oak tree (smallest)
What trophic level is at the bottom of the pyramid?
Level 1
What percentage of biomass from each trophic level is transferred to the level above it?
10%
What percentage of the incident energy from light for photosynthesis do producers transfer?
1%
4 ways biomass/energy is lost
-Egestion (lost in faeces)
-Excretion (removal of waste products e.g urine)
-Respiration (loss of CO2 and H20) where large amounts of glucose are used
-Production of inedible bones and shells
What is food security?
Having enough food to feed a population
6 factors affecting food security
-Increasing birth rates
-Changing diets in developed countries means scarce food
-New pests and pathogens affecting farming Conflicts
-Environmental changes affecting food production
-Cost of agricultural inputs
-Conflicts affecting waste and food availability
What must be found to feed all people on earth?
Sustainable methods
What is farming techniques?
Efficiency of food production can be improved by restricting energy transfer from food animals to the environment
How are farming techniques done?
-Limiting movement and controlling the temperature of their surroundings
-Feeding animals high protein foods to increase growth
Advantages of farming techniques
-Higher yield of food
-More efficient
-Allows easier quality control
Disadvantages of farming techniques
-Lead to antibiotic resistance
-High cost
-Reduce biodiversity
What are sustainable fisheries?
Fish stocks in the ocean are declining so it is important to maintain fish stocks at a level where breeding continues or certain species may disappear altogether in some areas
3 ways to maintain fish at a sustainable level
-Large sized holes in nets
-Bans on fishing during breeding season
-Strict limit on amount and type of fish caught (quotas)
What does biotechnology involve?
Using genetic modification to help with the demand of the growing human population
One example of a genetically modified food that improves nutritional value
Golden rice
3 reasons why crops are genetically modified
-Improve nutritional value
-Be pest resistant
-Be pesticide resistant
What do modern biology techniques enable?
Large quantities of microorganisms to be cultured for food
What is mycoprotein?
A protein rich food used to make meat substitute foods
What is useful for producing mycoprotein?
The fungus Fusarium
How is the fungus Fusarium grown?
It is grown on glucose syrup, in aerobic conditions, and the biomass is harvested and purified
What can genetically modified bacterium produce and how can this be used?
-Human insulin
-Used to treat people with diabetes when harvested and purified
