2.7. Ecology Flashcards
Define habitat
The habitat is the environment in which an organism lives in
Define population
A population is the total number of individual organisms of the same species living in the same geographical area
What is a community?
A community is made up of the populations of all the different species that live in the same habitat interdependently
e.g. the african grassland contains lots of species such as giraffes, zebras gazelles, as well as fungi and bacteria
Define the biotic part of the environment
The biotic part of the environment is the living part of the environment - the community
Define the abiotic parts of the environment
The abiotic part of the environment is the non-living parts of the environment
(e.g. amount of water, minerals in the soil)
Is the community the biotic or abiotic part of the environment?
The community contains all of the living organisms in an environment, therefore it is the biotic part of the environment
Define ecosystem
An ecosystem is the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment
Describe the different levels of organisation in an ecosystem
- Individual Organism
- Population
- Community
- Ecosystem
Why do organisms need resources from both abiotic and biotic parts of an ecosystem?
In order to survive and reproduce
Why do organisms compete for resources?
Because the resources are finite and in short-supply - and all organisms need them in order to survive and reproduce
Give 4 resources that plants compete for
- Light
- Space
- Water
- Mineral ions in the soil
Give 3 resources that animals compete for
- Food
- Mates
- Territory
Describe interdependence
Interdependence is when different species depends on other species. For example: for food, shelter, pollination, seed dispersal etc.
If one species is removed it can affect the whole community.
Give 4 examples of things that species may depend on each other for?
- Food (e.g. Animals eat other species like other animals or plants)
- Shelter (e.g. Trees)
- Pollination (e.g. Bees to spread polllen)
- Seed Dispersal
Describe what a stable community is
A stable community is one where all the species and environmental factors are in balance so that population sizes remain fairly constant
List the 7 abiotic factors that 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 respiration
Explain how light intensity is an abiotic factor that can affect a community
- Plants need light in order to carry out photosynthesis
- The light intensity affects the rate at which photosynthesis is carried out, which affects the rate of the growth of a plant
- This affects the food supply for animals and other species in a community as many rely on plants as a food source
If the light intensity is high:
- It increases the rate of photosynthesis, which means that plants and algae grow faster
- This means there is more of a supply of food to animals
If the light intensity is low:
- The rate of photosynthesis falls, which means that plants and algae grow slowly
- This means there may not be enough food supply for animals
Explain how temperature is an abiotic factor that can affect a community
- Different species of plants have different optimum temperatures for growth and survival and have different adaptations for temperature, so changes in the temperature of an environment could the distribution of species to change
- It is a limiting factor of photosynthesis, which means that it can affect the rate of photosynthesis, hence the rate of growth of a plant, and therefore the food supply for animals
- Also affects enzyme activity
Explain how temperature is an abiotic factor that can affect a community
- Different species of plants have different optimum temperatures for growth and survival and have different adaptations for temperature, so changes in the temperature of an environment could the distribution of species to change
- It is a limiting factor of photosynthesis, which means that it can affect the rate of photosynthesis, hence the rate of growth of a plant, and therefore the food supply for animals
- Also affects enzyme activity
Explain how moisture levels is an abiotic factor that can affect a community
- Plants and animals need water to survive, as without water there is no life
- Moisture is also required for decay in the soil to occur. Decay releases mineral ions in the soil, which plants can absorb
Explain how soil pH and mineral content is an abiotic factor that can affect a community
- Different plant species are adapted to different pHs, so the soil pH has a major effect on what plants can grow in the soil. (also as many plants cannot grow on soil that is too acidic or alkaline)
- A low soil pH also inhibits decay, which reduces the mineral ions in the soil which plants can absorb
- Different species of plants thrive in different nutrient concentration levels
Explain how wind intensity and direction is an abiotic factor that can affect a community
- It can affect the rate of transpiration in plants
- This can limit the distribution of plant species
Explain how carbon dioxide levels for plants is an abiotic factor that can affect a community
- Carbon Dioxide is needed for plants to photosynthesise, it is a limitng factor of photosynthesis
- This affects the growth of plants, which affects animal food supply
Explain how oxygen levels for aquatic animals is an biotic factor that can affect a community
- Oxygen in the air is constant, but the level of oxygen in the water varies
- If the oxygen level in the water is too low, it can kill or harm aquatic animals that live in the water
List 4 biotic factors that might affect a community
- availability of food
- new predators arriving
- new pathogens
- one species outcompeting another so the numbers are no longer sufficient to breed
How might the availability of food affect communities?
When there is plenty of food, organisms are able to survive and reproduce - increasing the population of the organism
When the availability of food falls, organisms struggle to survive and often do not reproduce - decreasing the population of the organisms
How might new predators arriving affect communities?
Organisms that have no defences against new predators may be quickly wiped out and cause the population of a prey species to fall
How might new pathogens arriving affect communities?
- If a new pathogen emerges and spreads, organisms have no resistance to the pathogen.
- This means the pathogen can damage or even wipe out populations in a community
How might one species outcompeting another so the numbers are no longer sufficient to breed affect communities?
It could cause the entire population in that community to become extinct
What are adaptations?
Adaptations are features that enable organisms to survive in the conditions in which they normally live
Need to see https://www.youtube.com/watch?v=KvK7EJimAH8&list=PL9IouNCPbCxVuf3dVIq6kHQ0b27Hu-fgW&index=3 to learn adaptation topic - no specific examples in spec
What are the three types of adaptations
- structural
- behavioural
- functional
Need to see https://www.youtube.com/watch?v=KvK7EJimAH8&list=PL9IouNCPbCxVuf3dVIq6kHQ0b27Hu-fgW&index=3 to learn adaptation topic - no specific examples in spec
What are food chains?
Food chains are the ways feeding relationships within a community can be represented
What do all food chains begin with?
All food chains begin with a producer
What are producers?
Producers are photosynthetic organisms (usually a green plant or alga) that use photosynthesis to make/synthesise glucose molecules, using energy from the Sun’s Light
What do producers do?
Producers synthesise their own food molecules
Most producers are usually…
Most producers are usually a green plant or alga which makes glucose by photosynthesis
Photosynthetic organisms are the producers of biomass for life on Earth
How?
Learn the statement too
They produce glucose through photosynthesis, which is then used to produce the chemicals that make up the cells of the plant. This new material adds to the biomass of the organisms
What is the source of all the biomass in a community?
Producers
What are primary consumers?
Primary consumers are the organisms that eat the producers
What are secondary consumers?
Secondary consumers are animals which eat the primary consumers
What are tertiary consumers?
Tertiary consumers are animals which eat the secondary consumers
What are primary consumers also known as?
Herbivores
What are secondary and tertiary consumers also known as?
Carnivores
What is similar about secondary and tertiary consumers?
They both eat animals
List the 4 levels of organisation in a food chain
- Producer
- Primary Consumer
- Secondary Consumer
- Tertiary Consumer
What do the arrows in a food chain represent?
The direction of biomass transfer
Define a predator and prey
Predators are the consumers that kill and eat other animals
Prey are the animals that are being killed and eaten by the predators
What happens to the number of predators and prey in a stable community?
In a stable community the numbers of predators and prey rise and fall in cycles
Explain how in a stable community the numbers of predators and prey rise and fall in cycles?
Use the example of foxes and rabbits
Also see https://www.youtube.com/watch?v=dRFQ8rZCK6Q&list=PL9IouNCPbCxVuf3dVIq6kHQ0b27Hu-fgW&index=4 for a better explanation
What happens to materials in the living world?
- All materials in the living world are recycled to provide the building blocks for future organisms
- Many different materials cycle through the abiotic and biotic components of an ecosystem
Give the names of two cycles that materials cycle through
- Carbon Cycle
- Water Cycle
What is the main thing the Carbon Cycle does?
The carbon cycle returns carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis
The amount of Carbon on the Earth is _______
The amount of carbon on the Earth is fixed
What are decomposers?
Decomposers are a group of microorganisms that cause decay by break down and feed on waste and dead organisms
What are decomposers also known as?
Microorganisms
Give examples of decomposers
Bacteria and Fungi
What do decomposers release?
What is their role/benefit?
Decomposers release:
- Carbon Dioxide through respiration for plants to take in later on
- Minerals ions into the soil for plants to reabsorb
Explain how the Carbon Cycle works
- The Carbon Dioxide in the atmosphere is removed by green plants and algae in photosynthesis
- The carbon is then used to make food molecules - carbohydrates, proteins and fats
- The carbon, in the form of food molecules, is then passed onto organisms that eat plants (primary consumers), and then passed onwards, up the food chain to even tertiary consumers
- Some of the carbon is then returned back into the atmosphere as carbon dioxide through the aerobic respiration of plants and animals
- The rest of the carbon is found in the waste products and dead remains of organisms
- The waste products and dead remains of organisms are broken down by decomposers
- As decomposers feed on them, they carry out respiration
- This releases carbon in the form of carbon dioxide back into the atmosphere
- Carbon Dioxide is also released when fossil fuels and wood are combusted/burned, as they contain large amounts of carbon that have been locked away by photosynthesising organisms for many of years
Why is the carbon cycle important?
What is it’s benefit?
The carbon cycle returns carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis, to provide energy for cell growth and other activities within the organism
Describe the water cycle
- The Sun’s energy causes water to evaporate from the seas and lakes on the Earth’s surface, turning the water into water vapour
- Water vapour is also formed as a result of transpiration - the loss of water vapour from plants - as well as respiration from animals because it produces water vapour
- Animals also lose water vapour from their urine, faeces and sweat
- As the water vapour rises, it rises into cooler air, where it cools and condenses to form clouds
- The water droplets in the clouds then get heavier and fall down as rain, hail, or snow, back to the Earth’s surface - known as precipitation
- The water then runs from the land, and forms streams that then flow into rivers, and eventually drain back into the sea
Explain how the water cycle benefits plants and animals
- The water cycle provides fresh water for plants to absorb via the plant roots
- The water cycle provides fresh water for animals to drink
Water in the water cycle is continuously ____________ and ____________
Water in the water cycle is continuously evaporated and precipitated
What are the three factors that affect the rate of decay / decomposition of biological material?
- temperature
- water
- availability of oxygen
