SB9 Ecosystems Flashcards
Define ecosystem
The collection of organisms in an area along with all of its environmental factors
–> including both biotic and abiotic factors
Define community
Groups of different species living together and interacting
Define population
Group of organisms of the same species, living at the same place at the same time
Define habitat
Place where an organism lives
Define interdependence
Organisms in an area need each other for resources, such as food. If you remove on species, it can affect the whole community
Define biotic factors
Includes all living factors such as plants and animals
Define abiotic factors
Includes all non living components, such as light intensity or soil moisture
Describe the levels of organisation within an ecosystem
- Producers
- Primary consumer
- Secondary consumer
- Teritary consumer
What is the role of a producer within a food chain?
Organisms that usually produce their own food, such as plants and algae, which photosynthesis
What is the role of a primary consumer in a food chain?
- herbivores
- eat the producers
What is the role of the secondary consumers?
- carnivores
- consume the primary consumers
What is the role of the teritary consumer?
- carnivores
- top of the food chain
- eat secondary consumers
How does temperature affect a community of plants?
Affects rate of photosynthesis
How does light intensity affect a community of plants?
As light intensity increases, plant photosynthesis increases, which increases its growth
How do moisture levels affect a community?
Plants and animals need water to survive
How do we calculate the total number of organisms in a sample?
total number of organisms in a sample x (total area pf study/ total area of quadrats)
What two methods can we use for sampling?
- Belt transacts
- Quadrats
Why must quadrats be laid randomly?
To avoid sampling bias
What are quadrats?
Square frames which are used in sampling
Describe how we can estimate the number of 3-leaf clovers in a 10m by 10m field using quadrats
- Divide the field into 100 even squares and use a random number generator to randomly select a single square
- Take a 1m x 1m quadrat and place it on the square
- Count the number of clovers in that square
- Repeat this again 4 times and take an average of the five samples
- Multiply the average by 100 to estimate the number of clovers in a field
Define transacts
A line along which samples are usually taken
Describe how to carry out a belt transact
- Lay out a measuring tape across the sample area
- Place quadrats at regular intervals along the tape and record the abundance of your chosen component
What biotic factors can species abundance be influenced by?
- competition
- predator prey relationships
- interactions with other organisms within the food chain or the food web
What abiotic factors can species abundance be influenced by?
- Light intensity
- Mineral availability
- Water availability
- pH
- Temperature
- Salinity
What are the limitations of using quadrats? State the problems and their relative solutions
- easy to miss individual organisms
ans: use a pencil and carefully move other organisms out of the way - identifying species can be tricky
ans: use a species identification guide