Ecology Flashcards
Ecology
The study of the interaction between groups of organisms and their environment
Energy flow
A food chain shows the energy flow from one organism to the next
Producer
Used the suns energy to make food through photosynthesis
Grazing food chains
always start with a producer
eg: grass -> grasshopper -> frog
Decomposer
Will break down dead organic matter and return nutrients to the ground (eg:) bacteria and fungi
Detritus Food Chain
Starts with dead organic matter (hummus) (eg:) fallen oak leaves
fallen leaves -> earthworm -> blackbird
The consumer
Eats the producer or other consumers
Grass -> rabbit -> fox
Primary consumer
Herbivore
Organism that feeds on the producer; eats vegetation
Secondary Consumer
Carnivore/Omnivore
Orgasm that feeds on the primary consumer
Tertiary consumer
Carnivore/ Predator
Organism that feeds on the secondary consumer
Food web
Consists of two or more food chains interlinked together
Trophic level
Refers to the feeding stages of an organism in a food chain
Eg: Grass T1 -> rabbit T2 -> Fox T3
Pyramid of numbers
a diagram showing the numbers of organisms at each trophic level/ stage in a food chain
size of individuals increase, number of individuals decrease
Inverted pyramid of numbers example
Oak -> greenfly -> mites -> bacteria
Niche
The functional role of an organism in an ecosystem
two species of the same niche can’t survive for long in the same habitat as they would be in competition
Limitations of pyramid of numbers
Numbers don’t account for the size of an organism
Parasitic food chains give rise to inverted pyramid
Numbers can be so great that it’s not drawn to scale
Biosphere
The part of the earth containing living organisms
Ecosystem
a community of organisms and their non living environment interacting together
Eg pond, woodland, bog
Habitat
The place where an organism lives and to which it is adapted
(nettle sting/ camouflage)
Abiotic factors
Non living factors
Aspect (direction a surface is facing)
Exposure (to wind, water and currents)
Salinity (salt concentration)
Aquatic Factors
Relate to organisms living in/ near water based environments
Light (may not penetrate)
Currents (may wash away algae, plants)
Wave action (creates currents physical damage to organisms)
Oxygen concentration (less co2 in water than air. gills)
Biotic Factors
Living factors
Food (more populous)
Predation (reduces number of prey)
Competition (scarce resources)
Parasitism (Reduces number of host organisms)
Human influences (increase of decrease no)
Animals (aid pollution and seed dispersal)
Climatic Factors
Temperature - grow faster in higher temperatures
Rainfall - need water to grow
Light Intensity - photosynthesis
Wind - increases evaporation and damage
Edaphic factors
Relate to the soil
Soil pH (prefer)
Soil type (sandy vs clay)
Humus (increases growth of plants)
Water, air and mineral content (increase growth of roots)
Population
A group of individuals of the same species living in a habitat
Eg number of daisies in a lawn
Size of population is determined by:
Competition
Predation
Parasitism
Symbiosis
Competition
Is the struggle for a resource that is in short supply
Competition occurs for
Food
space
mates
shelter
light
water and minerals
Two types of competition
Contest
Scramble
Contest competition
an active physical confrontation between two organisms which allows one to win
Eg two stags compete for mates
Scramble competition
Occurs when each organism tries to acquire as much of the resource as possible
Eg a thrush trying to feed too many chicks
Adaptions are developed
to avoid competition
Adaption example
Grass roots lie near the surface, tap roots of dandelion takes water from further down
Lady birds can fly and are red to warn others that they’re full of acid
Predation
Is the killing and eating of one organism (the prey) by another (predator)
Eg: Blackbirds are predators of earthworms
Adaptive techniques of predators
Catch large, rather than many small prey
Catch whatever is easy, prevents wasting energy
Able to move to areas of more plentiful prey
Adaptive techniques of Prey
Animals
Camouflage colouration (greenfly)
Warning colouration (peacock butterfly eyes)
Mimicry (hover fly looks like wasp)
Plants
Stings - nettles
Parasitism
Is a relationship in which one organism (the parasite) in or on another organism (the host) and from which it gets its food
Examples include disease causing bacteria like cholera bacterium, viruses, tapeworms, mould on leaves, fleas and ticks on animals
Endoparasites
Lives inside their host
Tapeworm
Ectoparasites
Lives on the outside/surface of the host
Fleas, athletes foot fungus
Symbiosis
Is a relationship between two species involving benefit
Clover (glucose) and nitrogen fixing bacteria (nitrate)
Bacteria (vitamin K) in large intestine (we give them food)
Mutualism
is where both organisms benefit form the relationship and neither suffers harm
Nitrogen fixing bacteria living in the root nodules of pea plants
Population fluctuations
Most populations in an ecosystem show fluctuations in numbers over a period of time
These fluctuations occur because
Births
Death
Immigration
Emigration
The effect of other species in the form of competition, predation, symbiosis
Why does the human population continue to rise despite war, famine, disease and contraception
healthcare eg vaccines
What are adaptations for
to help organisms increase their chance of survival
Grassland -> dandelion -> seeds have parachutes -> easily dispersed and no overcrowding
Grassland -> ladybird -> brightly coloured -> easily seen and recognised and avoided: acid
Why did you use a quadrat
Random sampling -> To avoid bias
5 flora
Grass
Doc leaves
Nettles
Buttercup
Daisy
5 Fauna
Birds
Mouse
Snail
Spider
Worm
Equipment used
Pooter
Pitfall trap
Beating tray
Sweep net
Quadrat
Study of animals - Capture recapture method
Capture
Mark
Release
Week later return
Recapture same amount
Count number marked
Calculate population size
C1 x C2
————
M2
Survey of an ecosystem - Abiotic factors
Soil pH - pH meter/ universal indicator
Soil temperature - soil thermometer
Light intensity - light meter
Nutrient recycling
nutrient recycling is the way in which elements are exchanged between living and non-living components of an ecosystem
this ensures no long term drain on the earths nutrients
Carbon is removed from the environment by:
Photosynthesis in plant
and under certain conditions over long periods of time, some of these plants may form fossils fuels such as oil, coal, peat and natural gas
Carbon dioxide is returned to the environment by:
Respiration in plants, animals and micro organisms
Decay caused by micro organisms
Combustion (burning fossil fuels)
Organisms involved in carbon cycle
Plants
Animals
Fungi and Bacteria (decomposer)
Global Warming (concentration on CO2 in air rising) Due to:
Increased burning of fossil fuels (coal oil)
Destruction of world’s forests (deforestation)
Increased levels of CO2 causes
global warming and acid rain
Nitrogen Fixation
Nitrogen fixing bacteria in the soil converts N2 gas in the air into nitrates - this accounts for the majority of all n2 fixation
Lightning storms and fuel burning in car engines produce nitrates (washed into soil water)
How is plant protein formed
Nitrates are absorbed by plant roots and converted to plant protein
How are animal proteins formed
Plant proteins are passed along food chains to become animal protein
When organisms die their proteins are converted to ammonia by bacterial decomposition
Nitrification
When organisms die their proteins are converted to ammonia by bacterial decomposition
Nitrifying bacteria in the soil then convert ammonia into nitrites then into nitrates
Nitrates can be absorbed by other plants to continue the cycle
Denitrification
Denitrifying bacteria convert soil nitrates into N2 gas
This is a loss of n2 from the cycle
Only happens in anaerobic conditions.
When O2 levels are low- due to flooding or accumulation of sewage
Nitrate also enters the cycle through the addition of nitrogen rich fertilisers to the soil - made industrially from N2 gas
Decomposition
Bacteria and fungi of decay turn to ammonia ( dead organic matter)
Simple: Nitrogen fixation
the conversion of nitrogen gas into nitrate
Simple: Nitrification
is the conversion of ammonia and ammonium compounds to nitrite and then nitrate
Simple: Denitrification
conversion of nitrates to nitrogen gas
Human impact on an Ecosystem
Pollution (grassland)
Conservation
Waste management
Pollution
Any harmful human addition to the environment
Most harmful human impact and affects air, fresh, water, sea, soil and land.
Pollutants are substances that caused pollution.
Types of pollution
Industrial/ air pollution
Agricultural pollution (slurry in river or pond)
Domestic pollution
River/ Water pollution
Effect of one pollutant from one area
Area: agricultural
Pollutant: slurry and fertiliser
Source: washed or leashes from land
Effects: formation of algal blooms and eutrophication
Eutrophication and Algal Bloom
Eutrophication: a condition where lakes/rivers become over enriched with nutrients from excess artificial fertilisers washed into rivers and lakes
There is a rapid increase in the growth of alga (algal bloom) as they use up the nutrients
When all nutrients are used up the algae die and are broken down by bacteria which use up the oxygen in the water resulting in the death of aquatic organisms such as fish
Control of pollutants
Area: agricultural
Pollutant: slurry and fertiliser
Control measures —> avoid spreading these on:
Wet, waterlogged, frozen or steeply sloping land
Within 1.5 m if any water course
Conservation
The management of our existing natural resources, in order to maintain a wide range of habitats and prevent the death and extinción of organisms
Benefits of conservation
Prevents organisms from becoming extinct
Maintains a balance of nature
Maintains a wide variety of living things
Organisms may be found to be useful in the future
Organisms and habitats are enjoyable to visit and see
We have no right to wipe out other life forms
Waste management
Role of micro organisms
Bacteria and fungi in both the soil and sewage break — down biodegradable materials
Control of waste production
Reduce
Reuse
Recycle
Important problems with waste disposal are:
Waste may cause disease
Poisonous chemicals from water can enter drinking water
Waste nutrients can result in eutrophication and death of aquatic plants and animals
Dumping at sea: pollution of the sea
incinerators may release toxic fumes
