Life Processes in the Biosphere Flashcards
What is the definition of a biome?
All examples of a geographical location with specific climate conditions and a characteristic community of species
What is the definition of an ecoystem?
A combination of biotic and abiotic features in an area
What is the definition of population?
All individuals of a single species in a particular area
What is an ecological niche?
The role a species play in its habitat, how it uses resources and its interspecies relationships.
What is the definition of species>
A group of organisms that more closely resemble each other than members of other groups and can breed to produce fertile offspring
What is taxonomy?
The science of grouping organisms into groups based on their similar features
What is carrying capacity?
The greatest population an area can support indefinitely
Why can population density play a role in mortality rates?
It is easier for disease to spread and food supplies to run out in a denser population
What is the calculation for population?
Starting population + births + immigrants - deaths - emigrants
What is a k-selected species?
Species that reach sexual maturity at an older age and produce few young but often live for a long time
What is an r-selected species?
Species that reach sexual maturity quickly, produce many young and disperse wildly
What are population dynamics? What are there two main biotic factors of this?
the processes that can cause populations to change in size and structure. Birth rate and Death rate
How do you estimate total number of species without having to discover all species?
Use past rate of discovery to estimate how many will be found until it plateaus
D = N(N-1) / (∑n(n-1)
What do D, N and n mean?
D = level of biodiversity
N = Total number of all organisms in an area
n = Total number of organisms of an individual species
What is the calculation for species diversity called?
Simpson’s Diversity Index
What is ecological stability?
How much the populations of species in an environment fluctuate
Why are more extreme environments less ecologically stable?
Species diversity is low, meaning there are fewer food species, a loss of one can have a major impact
What is secondary succession? Why is it faster than regular succession?
The re-colonisation of a habitat after its succession has been deflected. It is faster because the soil and seeds will already be there
Name 2 methods of managing/maintaining plagioclimaxes
- Grazing
- Burning
- Mowing
- Ploughing
- Felling
- Cutting
What is a plagioclimax?
A community of species where humans have stopped succession before the climax community
What is the final form of every sere?
Forest dominated by large trees
What happens to the geography of a psammosere?
organic matter and soil builds up until it becomes flat land
What is the first species to colonise a psammosere?
small plants
What happens to the geography of the a lithosere?
The bare rock is slowly covered by a layer of dirt until it is flat land
What is the first species to colonise a lithosere?
lichen or algae
What happens to the geography of a hydrosere?
The water is slowly filled by dead organic matter and soil until the area becomes flat land
What is the first species to colonise a hydrosere?
single-celled algae
What is the first species to colonise a sere called?
pioneer species
What are the important biotic factors that affect that can affect species distribution?
food supply, seed dispersal, pollination and disease
What 4 abiotic factors affect species distribution?
light, pH, water and mineral nutrients
Why does a large gene pool mean a species is more likely to survive changes to the environment?
Some individual will be adapted to new conditions
What is a range of tolerance?
The range of conditions in which a species can survive
