Biology - ecology Flashcards
How to use a quadrat to study the distribution of small organisms
Place a 1m squared quadrat on the ground at a random point within the first sample area. Usually find the point by using 2 rules at right angles from each other and using the random function on the calculator to provide coordinates.
Count all organisms within the quadrat
Repeat steps as many times as you can
Work out the mean number of organisms per quadrat within the first sample area
Repeat all steps in the second sample area
Compare the two means
Habitat
A place where an organism lives
Population
All the organisms of one species living in a habitat
Community
The populations of different species living in a habitat
Abiotic factors
non living factors of the environment, eg. temperature
Biotic factors
living factors of thew environment, eg. food
Ecosystem
The interaction of a community of living organisms with the nonliving parts of the environment
What resources do plants compete for
light
space
water
mineral ions
What resources do animals compete for
space (territory)
food
water
mates
Interdependence
In a community each species depends on other species for things like food, shelter, pollination and seed dispersal
What does the interdependence of all living things in an ecosystem mean
Means that any major change in the ecosystem can have far reaching affects
Stable communities
All the species and environmental factors are balanced so that he population sizes are roughly constant
Examples of stable communities
- tropical rainforest
- ancient oak woodlands
Examples of abiotic factors
- moisture levels
- light intensity
- temperature
- carbon dioxide levels (for plants)
- wind intensity
- oxygen levels
- soil pH and mineral content
How could a decrease light affect population size
A decrease in light intensity could decrease the rate of photosynthesis in a plant species. This could cause an affect on plant growth and cause a decrease in the population size.
How could a decrease in the mineral content of soil cause a decrease in population size
Decrease in mineral content of soil could lead to nutrient deficiencies. This could also affect plant growth and cause a decrease in the population size.
Examples of biotic factors
- new predators
- competition
- new pathogens
- availability of food
Adaptations
The features or characteristics that allows an organism to live in different environmental conditions.
Types of adaptations
- structural
- behavioural
- functional
Example of structural adaptations
- colour to help camouflage
- layers of fat to keep warm
- size of surface area to volume ratio
Example of behavioural adaptation
Many species migrate to warmer climates during the winter to avoid the problems of living in cold conditions
Functional adaptations
Things that go on inside an organism’s body that can be related to processes like reproduction and metabolism
Example of functional adaptation
Desert animals conserve water by providing very little sweat and small amounts of concentrated urine
What do food chains start with
Start with the producer
Producers
Make their own food using energy from the sun - usually green plants or algae
Biomass
The mass of living material - energy stored in plaNts
Organisms in the food chain
Producers
Primary consumers
Secondary consumers
Tertiary consumers
Predators
Consumers that hunt and kill other animals
What is the population of a species limited by
The amount of food available. If the population of prey increase then so will the predators, however as the population of predators increase then the prey will decrease
Distribution of an organism
Where an organism is found
How to use transects to study the distribution of organisms along a line
Marl out a line in the area you want to study using a tape meausure
Collect data along the line by just counting all the organisms you’re interested in that touched the line
Collect data by using quadrats
What does a change in distribution mean
Means a change in where an organism lives
Environmental changes that can affect the distribution of an organism
- change in the availability of water
- change in temperature
- change in the composition of atmosphere