C.1 species and communities Flashcards
What is a population?
Group of organisms of the same species that live within the same area at the same time
What is a community?
Group of populations interacting with each others in a certain area
What is an ecosystem?
Interaction between a community and its abiotic environment
What is a limiting factor?
Its a factor that puts an upper limit on the size of a population. Species within an ecosystem has ideal range of factors in which they thrive.
What are zones of intolerance?
They are outer limits of a species ideal environment, they limit the distribution of species as they are unable to tolerate too much variation from the ideal environment.
State limiting factors that affect plants
Temperature (Broccoli at 15, Maize at 25C), Water (Oak tree 200 litres per day), Light, Soil type, pH, Salinity
State limiting factors that affect animals
Temperature (Penguins can survive at 40C, Boa constrictors 24-30), Water (Indian elephant needs 300 litres per day), Breeding sites (Natal homing), Food supply (anteater only eats ants), Territory (Leopard territory of 32,000 km2), Salinity (freshwater crocodiles)
Explain how Marram grass lives within limiting factors
It grows exclusively on sand dunes. It has roots that are several metres long that allows it to find moisture deep within soil. It horizontal root networks which are ideal for stabilising dunes. It has temperature tolerance up to 40C with several features that reduces water loss. Wide pH tolerance from 4.5 to 9.5. Not tolerant towards salinity.
Explain how Polar bear lives within limiting factors
They have very thick layer of fur which means they can withstand low temperatures at lowest -37C. They have evolved to survive without the need of drinking water. They obtain water from the chemical break down of fat. They have large territories depending on breaking of ice and good food supply.
Explain how Giant panda lives within limiting factors
They almost exclusively eat bamboo. The temperature affects bamboos and therefore giant panda.
What is a transect?
It is a line across a habitat which is used to investigate the relationship between organisms and one or more abiotic factors. They help to establish zones of tolerance by observing where there are few organisms.
What is point sampling?
When points are marked at regular intervals along a transect. Forming a basic representation and is light on data.
What is continuous belt transect?
It is made up of a ‘belt’ of squares that are adjacent to each other. This generally provides a more detailed representation.
What is an interrupted belt transect?
It is essentially a combination of point and continuous belt sampling. It is when squares are placed with constant space between.
What is a model useful for?
It represents a simplified version of reality and can be used to understand how an object, system or concept works. It can also predict how it will respond to change.
Give examples of models
The mathematical model illustrating the predator/prey cycle by Lotka and Volterra. Diagrammatic model such as nutrient cycle or carbon cycle.
Disadvantages to modelling
- They rely on expertise to make them
- They can be interpreted in different ways
- They may not be accurate
- Different model may show different things
What is an ecological niche?
It is the sum of a species use of biotic and abiotic resources in its environment.
What is the fundamental niche?
Represent the broadest possible niche a species could live in. Within boundaries of limiting factors and with no competition.
What is a realised niche?
The actual mode of existence of a species. Taking into account limiting factors, competition, external pressures.
What is competitive exclusion?
Refers to the idea that two species with completely overlapping niches can not coexist. The one with greater selective advantage will out compete the other.
Who showed competitive exclusion in what experiment=
Russian ecologist Georgii Frantsevich Gause showed this in an experiment that focused on Paramecium. P. caudatum and P. aurelia. The two species were cultured seperately and thrived. However when cultured together P. caudatum was driven to extinction.
Define intraspecific interaction
When there is competition within a species
Define interspecific interaction
When there is competition between different species
