Life processes in the Biosphere Flashcards
What is ecological succession?
movement to colonise new habitats
What is the link between abiotically extreme environments and biodiversity?
Less abiotically extreme environments usually have higher biodiversity eg coral reefs
How can the levels of biodiversity be measured?
Simpsons Diversity Index
Simpsons Diversity Index
D= N(N-1)/Sum of n(n-1)
where:
N= Total number of organisms (all species)
n= Total number of organisms of an individual species
What is an r-selected species?
species that can respond quickly to low survival rates. They reach sexual maturity quickly, produce many young and can disperse widely eg mice.
What are K selected species?
Species that recover slowly from a decline in population. Reach sexual maturity at an older age, produce few young, but often live for a long time eg elephants
What is Maximum Sustainable Yield (MSY)?
The MSY of a population is an estimate of the greatest exploitation that is possible without causing unsustainable long-term population decline
What are density independent factors?
These include factors where the population density has no effect on the chances of survival of an individual eg drought, flood
What are density dependent factors?
Factors where the chances of an individual surviving depend on the population density. eg food supply, disease
What is carrying capacity?
the greatest population that an area can support indefinitely without damaging or over exploiting the environment- mortality rate can change so a population can return to its carrying capacity
What is evolution?
the process that changes the gene pool of a species, driven by the increased chance of survival
Define Biome
Area with a distinct climate and characteristic community
Define ecosystem
biotic components and abiotic components all interacting together in a system and as a unit
Define Habitat
the location where an organism/biological population lives, resides or exists
Define community
A group of populations of two or more species occupying the same geographical area at the same time interacting with one another
Define Population
A subset of individuals of one species that occupy a particular geographic area and interbreed
Define species
A group of organisms that can freely interbreed to produce fertile offspring
What is a niche?
How an organism fits into it’s environment, including it’s interactions with the physical environment and with other species it interacts with
Describe how the loss of forest ecosystem services can impact humans (6 marks)
1) Loss of wildlife habitat meaning less food resources and loss of potential characteristics in agricultural species (for breeding programs).
2) Reduced root binding of soil meaning more soil erosion which means loss of land that supports agriculture
3) Reduced interception which could result in flooding of homes etc
