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Environment
All the external factors that influence an organism
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What is ecology?
Ecology is the study of how living things relate to each other and to their environment
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What is an ecosystem?
An ecosystem is a group of clearly distinguished organisms that interact with each other and their environment as a unit
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Community
A community is all of the organisms in an ecosystem
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Population
A population is all the members of the same species in an ecosystem
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What is a biosphere?
The biosphere is the part of the planet containing living organimss
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What is a habitat?
A habitat is the particular place within the ecosystem where an organism lives
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Environmental factors that affect organisms
- Abiotic - non living factors
- Biotic - living factors
- Climatic - weather conditions over a long period of time
- Edaphic - factors referring to the soil
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Abiotic factors
- Temperature of land and water
- pH
- Light intensity
- Water
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Biotic factors:
- Plats - food and shelter
- Predators - reduce number of prey
- Prey
- Parasites
- Humans (pollution)
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Edaphic
- Soil pH
- Available water
- Air and mineral content
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Aquatic factors
- Light penetration
- Currents
- Wave action
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What are producers
Producers are organisms that carry out photosynthesis
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What are primary consumers
Primary consumers feed on producers
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What are secondary consumers
Secondary consumers feed on primary consumers
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What is the food chain
A sequence of organisms in which each one is eaten by the next member in the chain
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A grazing food chain is..
One where the initial plant is living
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A detritus food chain is..
One where the chain begins with dead organic matter and animal waste (detritus)
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What is a food web
2 or more interconnected food chains
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What is tropic level
Refers to position of an organism in a food chain
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Limitations of pyramid of numbers
Size (e.g. Single rosé bush can support thousands of green flies) INVERTED
distorted when parasites
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What is a niche
A niche is the functional role of an organism in an ecosystem
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Carbon dioxide is returned to the environment by
- 1. Respiration in plants, animals and microorganisms
- 2. Decay caused by microorganisms
- 3. Combustion ie. fossil fuels
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Nitrogen gas must first be..
Nitrogen gas must first be 'fixed' ie changed to a suitable form (ammonia in nitrate)
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Why do organisms need nitrogen?
Protein, DNA and RNA manufacture
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Nitrogen fixation is
A conversion of gaseous nitrogen to a form that can be used by organisms
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Nitrification is
The conversion of ammonia to nitrites and then to nitrates
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Denitrification is
The conversion of nitrates into nitrogen gas
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What is pollution
Pollution is any undesirable change to the environment
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What is eutrophication
A condition where lakes become over enriched with nutrients, resulting from excess artificial fertilisers washed into rivers and lakes
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How to control slurry pollutant
Avoid spreading on wet, frozen, sloping land
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Cause of acid rain
Fossil fuels release acidic CO2 and SO2
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Problems with acid rain
- Erosion of limestone
- Lower soil pH
- Breathing problems
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Solutions of acid rain
- Burn less fossil fuels
- Switch to clean energy
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What is conservation
Conservation is the protection and wise management of natural resources and the environment
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Benefits of conservation
- Existing environments are maintained
- Endangered species are preserved for reproduction
- The balance of nature is maintained
- Pollution and it's effects are teduced
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Problems with waste disposal
- Availability of suitable landfill sites
- Toxic or polluting content of fumes from incineration
- Decaying waste produces methane
- Harmful substances may leak into ground water supplies
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Solutions for waste disposal
Use microorganisms
Reduce reuse recycle
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Accumulated fish waste leads to
- Unpleasant odours
- Infestation of rats
- Maggots
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Managing fishery waste
- Animal feeds and oils
- Fish offal is converted to fish meal and this is sold as animal Feed
- Oil is extracted, refined, health food supplements
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Factors that control population
- 1. Completion
- 2. Predation
- 3. Parasitism
- 4. Symbiosis
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Animals live in populations because
- Food and shelter
- Safer in a group
- Availability of a mate for breeding purposes
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What is competition
When organisms of the same or different species "fight" for the necessary resources that are in short supply
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Intra specific competition
Between members of the same speoes
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Inter specific competition
Between members of different species
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Plants compete for..
Light, water, minerals and space
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Animals compete for..
Food, water, shelter, territory and mates
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Contest competition
Involves an active physical confrontation between two organisms
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Scramble competition
Is when each organism tries to acquire as much of the resource as poddible
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Competition and population size..
- Restricts population size
- Only successful competitors survive and reproduce
- A driving force behind ecolutoon
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How do animals survive competition?
- Changing feeding habits
- Camouflage
- Producing protective costs
- Moving away from over populated areas
- Plants
- Produce large number of seeds
- Plants thrive even in poorer soil conditions
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What is predation
The act of some animals capturing and killing other animals for food
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Predators are
Animals that hunt, kill and eat other animals for food
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Positive effects of predation
- Stabilises the community
- Control the number of herbivores, prevent overgrazing
- Eliminate the less well adapted prey
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Adaptions of predators
- Keen senses and sharp teeth
- Catch easiest prey, old and sick
- Live and hunt in packs
- Migrate to where prey is plentiful
- Camouflage
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Examples of adaptions of predators
- Hawks have good eyesight
- Cheetahs can run at 60km/hr
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Adaptations of prey
- Plants have thorns, spines or stings
- Nasty taste when eaten
- Are faster than their predators
- Safety in numbers
- Camouflage
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What is parasitism
One organism, the parasite, benefits from another, the host, and does harm to it
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Symbiosis
Where two organisms of different species have a close relationship where at least one of them benefits
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Factors that contribute to predator prey relationships
1. The availablity an abundance of food
- 2. Concealment
- Less prey, hide better. Allows population to survive and increase
- 3.Movement of prey and predators
- When not enough food, prey will migrate
- Predator moves to area with more pret
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Population increase because
- Immigration to new area
- Rise in birth rates
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Population decrease because
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4 factors that affect human population
- 1. Famine
- 2. War
- 3. Disease
- 4. Contraception
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