Ecology (chpt. 4, 5, 6) Flashcards
Ecology
The study of the interaction between organisms and their abiotic environment
Ecosystem
A community of organisms and their abiotic environments
E.g. grassland, tropical rainforest
Biosphere
The part of the earth inhabited by living organisms
Habitat
Where a plant or animal lives
Population
All the members of the same species living in the same area / habitat
Environmental factors affecting organisms (x4)
- biotic factors
- abiotic factors
- climatic factors
- edaphic factors
What are biotic factors?
Living factors such as food, competition, predation, pollination and human intervention
Competition
Fight for scarce resources
Food, space, mates
What are abiotic factors?
Non-living factors such as altitude, aspect, exposure, currents and temperature
What are climatic factors?
Refers to the effect of the weather over a long period such as light intensity, temperature, rainfall and wind
What are edaphic factors?
Relate to soil such as, ph, soil type, humus content and mineral content
What environmental factors affect aquatic environments?
- light penetration
- currents
- salt content
- oxygen concentration
Producer/autotroph
An organism that makes its own food
Consumer / heterotroph
An organism that takes in food from another organism
Herbivore
Eats plants only e.g rabbit
Carnivore
Eats other animals only e.g fox
Omnivore
Both plants and animals e.g. Hedgehog, Sparrow
Decomposer
Feeds on dead organic matter e.g. Earthworm, bacteria
Saprophyte
Bacteria and fungi that feed on dead organic matter
Primary consumer
An animal which feeds on producers e.g herbivores, decomposers
Secondary consumer
An animal that feeds on primary consumers e.g. Carnivores, scavengers
Tertiary consumers
Feed on secondary consumers
Trophic level
Feeding stage in a food chain
Grazing food chain
A sequence of organisms in which one is eaten by the next member in the chain
* starts with a producer
Basic food chain layout
Producer → primary consumer → secondary consumer → tertiary consumer
Example of a food chain
Buttercup → caterpillar → blackbird → fox
Grass → rabbit → fox
Food web
Consists of two or more interlinked food chains
Pyramid of numbers
A diagram which shows the numbers of organisms at each stage in a food chain
Limitations to the pyramid of numbers (x2)
- Doesn’t take into account the size of the organism
- can’t be drawn to scale
Niche
The functional role of an organism within the habitat
Nutrient recycling
The way in which elements, e.g carbon and nitrogen, are exchanged between the living and non-living components of an ecosystem
Why is the carbon cycle important?
- Balance carbon dioxide levels
- photosynthesis is the basis of food chains
Role of plants in the carbon cycle
Remove carbon dioxide during photosynthesis and return small amounts during respiration
Role of animals in the carbon cycle
Take in carbon dioxide by eating plants and release in respiration
Role of microorganisms in the carbon cycle
Return carbon dioxide when decomposing dead plants and animals
DRAW carbon cycle
DRAW nitrogen cycle
Role of fungi in the nitrogen cycle
Act as decomposers
Role of plants in the nitrogen cycle
Absorb nitrates from soil to make proteins
Role of animals in the nitrogen cycle
Consume plants and use it to form animal protein
(Egestion and waste products )
Role of humans in the nitrogen cycle
Add nitrogen rich fertilisers to the soil and uses manure
Why must nitrites be converted to nitrates
So it can be used by other organisms
Pollution
The addition of harmful substances to the environment
Pollutant
Harmful substances that cause pollution (undesirable changes)
Types of pollution (x3)
- domestic pollution → household waste, plastic bags
- agricultural pollution → use of sprays to control pests, overuse of fertilisers
- industrial pollution → gases that may cause acid rain or damage rivers
Global warming
Carbon dioxide forms an insulating layer which allows sun through but stops much of it escaping out to space
Sources of greenhouse gases
Burning fossil fuels, deforestation
Effects of global warming
- sea levels may rise
- increased frequency of extreme weather
- increased plant yield
Example of a domestic pollutant (name, source, effect, control)
Pollutant: plastic bags
Source: shopping, packaging
Effect: non-biodegradable, litter
Control: bag tax, reuse, recycle
Conservation
The wise management of our existing natural resources to ensure the survival of organisms and their habitats
Benefits of conservation
- prevents extinction
- maintains balance of nature
- organisms way be useful in future
- enjoyable to see and visit
Example of conservation
fishing industry → fish quotas are set to ensure that enough fish are left to replenish the stocks
Waste management
Involves preventing pollution and conserving the environment
Waste management - agriculture
Slurry is spread on dryland to prevent runoff into rivers → improves water qualify
Waste management - fisheries
Waste parts of fish are neutralised, pulped, dried and recycled as fertiliser or pig food
 Waste management - forestry
Tops of trees and large branches are converted to sawdust, which is used to form processed wood
Problems associated with waste disposal
- waste may contain disease-causing microorganisms
- toxic chemicals that are released can enter drinking water supplies
- waste in landfills canbe unsightly and produce unpleasant smells
- fear that poisonous gases may be released during incineration
Role of microorganisms in waste management
- compost bins - bacteria and fungi feed on waste and break it down into compost
- bacteria can be used to digest oil spills
Steps in waste minimisation
- Reduce
- Reuse
- Recycle
Ecosystem
Organisms and their environment
Why is the earth considered an ecosystem?
No part of the earth is completely isolated from the rest
Name the part of the earth where life can exist
Biosphere
How is the pooter used?
Suck through and animal enters on other side
How is the tullgren funnel used?
Heat causes animals to move downwards
