Lecture 3 Flashcards
(31 cards)
What are the three levels of biodiversity that are usually explored?
1- Genetic Diversity
2- Species Diversity
3- Ecosystem Diversity
What are the four levels of organisation?
1- Species
2- Population
3- Community
4- Ecosystem
What is a species?
A species is a group consisting of all the collected populations of morphologically and genetically similar organisms that are able to interbreed with one another.
What is a population?
A population is defined as consisting of all the individuals of the same species within a defined geographical area that show some degree of reproductive isolation from other populations.
What is a community?
Biological community refers to all the interacting populations in a specific area or region at a certain time.
What is species richness?
The measure of the number of species which occur within a particular taxonomic level in a given region.
What is species diversity?
The number of different species and the relative abundance of each species in a biological community.
What are the factors that can change local species diversity?
Speciation
Extinction
Immigration
Emigration
What does diversity represent?
The health of the ecosystem.
What is the Diversity/Stability hypothesis?
Higher stability strengthens a community’s ability to be able to resist disturbance and invasion and/or recover rapidly from a perturbation.
What benefit does a higher species diversity have in biological communities?
It buffers the risk of ecological collapse.
What are functional traits?
Traits that define species in terms of their ecological roles, how they interact with the environment and other species.
What is functional diversity?
The variety of biological processes, functions or characteristics of a particular ecosystem.
What is Latitudinal diversity gradient? (LDG)
- increase in species richness towards the tropics
-in marine, freshwater and terrestrial species
-virtually all major taxonomic groups
-peak is seldom at the equator but often ~20-30 degrees north
What are 1&2 of the trends of Elevation diversity gradient (EDG) ?
- decreasing richness with increasing elevation
-plateaus in richness across low elevations (<300m from base)
What are 3&4 of the trends of Elevational Diversity Gradient (EDG) ?
-decreasing with or without a mid-elevation peak ( 4300m elevation)
- a unimodal pattern with a mid-elevation peak
What are the features of Latitudinal Diversity Gradient?
- Climatic
- Spatial
- Historical
- Evolutionary factors
What are the features of Elevational Diversity Gradient?
- Climatic
- Spatial
- Biological processes
- Evolutionary factors
What are the measures of diversity?
- Alpha diversity within habitat (local/site diversity)
-Beta diversity
-Gamma diversity
What can we measure in Biodiversity?
- Species richness
- Abundance
- Diversity (relationship between richness and abundance)
What are the factors related to variability in patterns of small scale species richness among communities?
-geographic factors such as scale of observation, available species pool and dispersal patterns
- biotic factors such as competition or predation
-abiotic environmental factors such as site resource availability, disturbance and physical conditions
What is Beta diversity?
Number of distinct compositional units in the region / number of different communities in the region
What is species richness (s) ?
Total number of species identified per unit area - simplistic descriptor of community structure
What are species richness counts highly sensitive to?
- the number of individuals sampled
-the number of samples
-size of samples
-special arrangement of samples
