Biodiversity Flashcards
What is Biodiversity?
How much variety we have with regards to species & ecosystems within a given habitat.
What is an Ecosystem?
A biological community living within a region with particular physical surroundings.
There are interactions or relationships within the community. These can be either ?, ? or ?
Beneficial, Harmful or Benign.
In order to survive and reproduce, organisms must adapt to both biotic and abiotic factors.
Define Biotic Factors:
Those that relate to living organisms that affect an ecosystem.
Name the 5 different types of biotic factors
- Humans
- Plants
- Bacteria
- Diseases
- Predators
Define Abiotic Factors
Non living physical and chemical factors that influence organisms & ecosystems.
How do biotic factors impact the environments population?
Via predation, parasitism, disease etc
Give 5 examples of abiotic factors
- Climate
- Sunlight
- Humidity
- Shelter
- Pollutants
What do abiotic factors impact?
Growth and reproductive abilities of organisms
Name 6 different methods of measuring species diversity
- Species Richness
- Relative Species Abundance
- Percentage Frequency
- Percentage Cover
- Simpson’s Diversity Index
Define Species Richess (S)
What is the species richness in the image above?
A measurement of the number of different species in an ecosystem.
It does not take into account the populations of each species, or how even/uneven the populations are compared to each other.
There is a species richness of 3 (butterlies, ants & snakes)
What is Relative Species Abundance?
What does it tell us?
How is it expressed?
This measurement refers to how common or uncommon a species is relative to its surroundings. The word evenness may be used to descrive relative species abundance.
It tells us how concentrated a population may be in a particular ecosystem.
It can be expressed as a % or as an exact population.
(page 3 of ATAR book)
Percentage Frequency
What are the square grids called that are used when sampling percentage frequency?
What does percentage frequency measure?
Quadrats
Percentage frequency measures the probability that a species will be found in a single quadrat.
To calculate percentage frequency:
% Frequency = no. of quadrats in which species is found x 100%
total number of quadrats
Percentage Cover - what does % Cover tell us?
What sort of organisms is this typically used for?
When is it a good idea to use % Cover
What can be combined with % Cover to draw bigger conclusions about a particular species.
Percentage cover tells us how much space a species occupies in a particular sample we take. It is more related to geographic spread of a species.
It is typically used for organisms that don’t move around much.
It is a good idea to use % cover when it is impossible to count the number of individual organisms.
Using both % frequency and % cover allows us to draw bigger conclusions about a particular species.
What is the name of the Diversity Index that is the most important & comprehensive measurement of diversity within an ecosystem?
Why?
Simpsons’s Diversity Index
It accounts for both species richness & evenness.
As species richness & evenness increases, the overall diversity will increase.
