Unit 3, Topic 1 Describing Biodiversity Flashcards
Biodiversity, Classification of Organisms and Ecosystems
What is biodiversity?
The number and variety of organisms in a geographical area. Can be measured at genetic, species, ecosystem levels.
Genetic diversity:
refers to variation of genetic types within a species
Species diversity:
refers to number of different species
Ecosystem diversity:
refers to the variety of different types of habitats or ecosystems available
What is species richness?
This is the number of different species in an ecosystem. It takes no notice of abundance and gives as much weight to those species which have very few individuals as to those who have thousands.
What is species evenness?
This is a measure of the relative abundance of the different species. A community dominated by one or two species is considered to be less diverse than one in which several different species have a similar abundance.
Why do we use percentage cover?
If we want to know what kind of plants are in a particular habitat, and how many there are of each species, it is usually impossible to go and count each and every one present. Therefore, we use a quadrat and estimate percentage cover.
What is percentage frequency and it’s formula?
This is the probability that a species will be found within a single quadrat.
Percentage frequency = (number of quadrats in which the species is found/total number of quadrats) x 100
In the Simpsons Diversity Index formula what does each symbol/letter mean?
D=1-( (∑n(n-1))/(N(N-1)))
∑ = sum of
n = number of individuals
N = total number of individuals
The value of Simpsons Diversity Index ranges between 0 and 1. What does an index closer to 1 represent?
The greater the index value, the greater the sample diversity.
What are some problems associated with the percentage cover method of determining species diversity?
Very subjective. One drawback of this method is that plants in flower tend to be over-estimated while low-growing plants are under-estimated.
What are two primary ways ecosystems can be compared?
Ecosystems can be compared across spatial scales (size) and temporal scales (time).
Why is understanding spatial and temporal scales important in studying ecosystems?
To predict ecosystem responses, it’s essential to account for biological and physical interactions across scales ranging from local to global (spatial) and from hours to decades (temporal).
What does a spatial scale refer to in ecosystem studies?
Spatial scale refers to the size of the ecosystem being studied, ranging from small, local areas to entire continents or oceans.
Large scale: An entire continent or ocean.
Medium scale: A mountain range or desert.
Small scale: A specific forest, paddock, or mountain.
What does a temporal scale consider in ecosystem studies?
Temporal scale considers the ecosystem over a specific timeframe, from hours to years or even decades.
Small scale: Hours to days.
Medium scale: Seasonal changes.
Large scale: Years to decades (e.g., ecological succession).
