ecology Flashcards
What is the relationship between an individual, species, habitat, and population?
An individual is part of a species, but lives in its habitat within a population.
How are communities created?
- Many different populations interact in the same habitat, creating a community.
- The populations are often dependent on each other.
Define an ecosystem
- An ecosystem is the interaction of a community with non-living (abiotic) parts of the environment.
- Organisms are adapted to live in the conditions of their environment.
What happens when organisms need the same resources?
- Organisms which need the same resources compete for it.
- There can be competition within a species or between different species.
What may plants compete for?
- Plants may compete for light, space, water and mineral ions.
What may animals compete for?
- Animals may compete for space, food, water and mating partners.
Define interdependence
- Interdependence describes how organisms in a community depend on other organisms for vital services.
Give examples of interdependence
- These include for food, shelter and reproduction (pollination, seed dispersal), e.g.
birds take shelter in trees, flowers are pollinated with the help of bees.
What can the removal or addition of a species affect and why?
- The removal or addition of a species to the community can affect the populations of
others greatly, as it changes prey or predator numbers
Describe a stable community
- A stable community is one where all the biotic (living) and abiotic (non-living) factors
are in balance. - As a result the population sizes remain roughly constant.
- When they are lost it is very difficult to replace them.
Give examples of a stable community
- Tropical rainforests, oak woodlands and coral reefs
Define an abiotic factor
- An abiotic factor is a non-living factor
Name the abiotic factors which 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 aquatic animals.
Explain the effect of light intensity on a community
- Light is required for photosynthesis.
- The rate of photosynthesis affects the rate at which the plant grows.
- Plants can be food sources or shelter for many organisms.
Explain the effect of temperature on a community
- Temperature affects the rate of photosynthesis.
Explain the effect of moisture levels on a community
- Both plants and animals need water to survive.
Explain the effect of soil pH and mineral content on a community
- Soil pH affects the rate of decay and therefore how fast mineral ions return to
soil (which are then taken up by other plants). - Different species of plants thrive in different nutrient concentration levels.
Explain the effect of wind intensity and direction on a community
- Wind affects the rate of transpiration (movement of water from root to leaves)
in plants. - Transpiration affects the temperature of the plant, and the rate of
photosynthesis because it transports water and mineral ions to the leaves.
Explain the effect of carbon dioxide levels on a community
- CO2 affects the rate of photosynthesis in plants.
- It also affects the distribution of organisms as some thrive in high CO2
environments.
Explain the effect of oxygen levels for aquatic levels on a community
- Levels in water vary greatly, unlike oxygen levels in air.
- Most fish need a high concentration of oxygen to survive.
Define a biotic factor
A biotic factor is a living factor.
Name the biotic factors which can affect a community
- Availability of food
- New predators arriving
- New pathogens
- One species outcompeting another so the numbers are no longer
sufficient to breed
Explain the effect of food availability on a community
- More food means organisms can breed more successfully and
therefore the population can increase in numbers
Explain the effect of new pathogens on a community
- When a new pathogen arises the population has no resistance to
it so they can be wiped out quickly
Explain the effect of competition on a community
- If one species is better adapted to the environment than another,
then it will outcompete it until the numbers of the lesser adapted species are
insufficient to breed.
How do organisms survive the conditions in which they normally live in?
- Organisms have features (adaptations) that enable them to survive in
the conditions in which they normally live.
What kind of adaptations can an organism have?
- These adaptations may be structural, behavioural or functional.
Define a structural adaption
- The shape or colour of a part of an organism
Give examples of structural adaptations and explain how they help an organism
- Sharp teeth of a carnivore to tear meat apart
- Camouflage, such as the tan/brown colour of a lionesses coat, to avoid prey
from spotting her - Species in cold environments may have a thick layer of fat for insulation
Define a behavioural adaption
- The way an organism behaves
Give examples of behavioural adaptations and explain how they help an organism
- Individuals may play dead to avoid predators
- Basking in the sun to absorb heat
- Courting behaviour to attract a mate
Define a functional adaptation
- Involved in processes such as reproduction and metabolism
Give examples of functional adaptation and explain how they help an organism
- Late implantation of embryos
- Conservation of water through producing little sweat
Define an extremophile
- Extremophiles are organisms that live in environments which have extreme conditions.
- These include high temperatures, pressures or salt concentrations.
Give an example of an extremophile
- An example is bacteria which live in deep sea vents where the pressure is very high.
Give an example of adaptations in cold climates and how they help an organism
- Smaller surface area to volume ratio to reduce heat loss, lots of insulation (blubber, fur coat)
Give an example of adaptations for dry climates and how they help an organis
- Adaptations to kidneys so they can retain lots of water producing very concentrated urine, being active in the early morning and evenings when it is cooler, resting in shady areas, larger surface area ratio to increase heat loss
Give examples of plant adaptations and how they help an organism
- Curled leaves to reduce water loss
- Extensive root systems to take in as much water as possible
- Waxy cuticle to stop water evaporating, water storing tissue in stem
What do food chains show?
- Feeding relationships are shown by food chains.
Describe the food chain
- They begin with a producer.
- Producers are eaten by primary consumers – energy is transferred through
organisms in an ecosystem when one is eaten by another. - Primary consumers are eaten by secondary consumers – The animals eaten are
called the prey and the consumers that kill and eat them are predators. - Secondary consumers are eaten by tertiary consumers.
Describe a producer
- These are always photosynthetic organisms (usually a green plant or algae)
How do producers make glucose and what is it used for?
- Through photosynthesis they make glucose
- Glucose is used to make other biological molecules in the plant, which make
up the biomass
How do you work out the distribution and abundance of species?
- To work out the distribution and abundance of species in an ecosystem, tools called transects and quadrats are used.
- You can then process this information by calculating the mean, mode and median and then drawing a graph.
What will a stable community show?
- A stable community will show population cycles between the predators and prey.
Explain how population cycles between predators and prey work
- If the population of prey increases, the population of predators will also increase.
- This will result in the number of prey decreasing after some time as more would be
consumed by the increased number of predators. - When there isn’t enough prey to feed all the predators, the population of predators will decrease, which will allow the population of prey to increase again
Name two cycles vital for life o earth
- The carbon and water cycles are vital for life on Earth.
- Lots of different materials are cycled through an ecosystem
Explain how the carbon cycle works
- CO2 is REMOVED from the air in photosynthesis by green plants and algae – they
use the carbon to make carbohydrates, proteins and fats. They are eaten and the
carbon moves up the food chain. - CO2 is RETURNED to the air when plants, algae and animals respire.
Decomposers (a group of microorganisms that break down dead organisms and
waste) respire while they return mineral ions to the soil. - CO2 is RETURNED to the air when wood and fossil fuels are burnt (called
combustion) as they contain carbon from photosynthesis
Explain how the water cycle works
- The sun’s energy causes water to evaporate from the sea and lakes, forming water
vapour. - Water vapour is also formed as a result of transpiration in plants.
- Water vapour rises and then condenses to form clouds.
- Water is returned to the land by precipitation (rain, snow or hail), and this runs into lakes to provide water for plants and animals.
- This then runs into seas and the cycle begins again
Name the factors that affect the rate of decomposition
- Temperature
- Water
- Availability of oxygen
How does temperature affect the rate of decomposition?
- Chemical reactions generally work faster in warmer conditions, but if
it is too hot the enzymes can denature and stop decomposition.