Biodiversity And Biodiversity Threats Flashcards
What are some of the different ways to measure biodiversity through distributions?
Polygons
Points
Systemic Assessment of all species within a specific area.( can be done in a larger area however there is a risk of not completing , can also be done on a smaller plot where completion is much easier)
What is meant by distribution through a polygon?
Polygons are areas where organisms can be found. They normally provide basic information on species distribution .they are super reliable on a small scale by about 1 degree.
What is meant by distribution through points.
This is an alternate to polygons. This refers to all the places where an organism is known to be from.
A lAck of point data maybe be because :
The species does not occur in that location
The species was not seen there
No one has tried to look for the species in that area
The species may be there but may not be accounted for in the database being used.
Are the following statements true or false :
We know a lot but we know about more species than others .
We know a lot but we know about more areas than others .
An area has more data available if there are more people ( in particular more scientists)
All three statements are true .
Answer true or false to the following
Geographically we know that the most undescribed species are found in poorly studied areas.
Taxonomically we know that poorly studied groups have the most undescribed species.
>90% of mammals are known while<20% of insect are known
All three statements are true .
How many types of diversity are there ?
Taxonomic diversity : this is refers to the variety of species in an area. This is just stacking polygons on top of each other.
Phylogenetic diversity : this is the measure of the evolutionary history of species. Phylogenetic diversity of an area is the total length of the tree of the species found there (for each area we can calculate how many million years if evolution are represented by the species found there). There is timeCalibrated phylogenetic diversity.
Functional diversity : is a category of diversity where species are grouped based on the functional traits they have ( functional traits are traits that impact the ecosystem).
What are some factors to note about heterogeneity
- Species may not be overlapping: different species occupy different areas in an ecosystem.
- Split into communities maybe sharp or abrupt . With this when you move from one community to another in the same ecosystem there will a sudden noticeable difference . Eg of this would be moving from a terrestrial community into an aquatic ecosystem in the case of river dolphins and monkeys.( in such an ecosystem if only a small area is sampled you will get one species or the other but never both because they hardly interact).
- Sometimes splits into communities have gradual and example of this will be the climate changing gradually as you move up a mountain.
What are the three types of heterogeneous diversity and describe each.
Alpha diversity : this usually refers to the diversity in an ecosystem usually expressed but the number of species variety ( I.e species richness) there is in an ecosystem.
Beta diversity: this is usually the change in species composition between two ecosystems . This is is usually the count of unique species of a particular ecosystem.eg the beta diversity of two ecosystems (woodland and hedgerow) is 7, this would be 5soecues unique to only woodlands I.e cannot be found on hedgerow and 2species unique to only hedgerow I.e cannot be found in woodland.
Gamma diversity : this refers to the overall species diversity in a large scale area or ecosystem. Accounts for all species in the entire study area.
Why is diversity higher near the equator?
Diversity is higher near the equator because climate conditions near the equator are more stable, organisms tend to thrive in climates that are more stable. Diversity requires a long time to build.
Are the following statements true or false .
Species are only endemic to an area if they are only found in that particular area.
Technically all species are endemic to earth.
Endemicity can be defined for any taxa level I.e larger or smaller.
All three statements are true.
Answer true or false to this statement .
Scientific adaptations are required to live in cold and dry areas and therefore cold and dry areas have fewer species.
True.
What is the correlation between stability and endemicity.
Some species are very bad at dispersing this could be because they have very specific conditions within which they thrive. In such cases they require stability in climate conditions because a fast change in climate could result in death .
What can you say about area and diversity?
Larger areas have more diverse population.
Larger populations have lower stochastic extinction rates ( i.e normally random events or happenings that cause extinction.)
Smaller populations are more susceptible to diseases and have a higher chance or being wiped out by a disaster.
What can you say about isolated areas.
Isolated areas have very few species and most of the species maybe endemic to that region. ( fewer species may be adapted raptor live there because there may be lack of food for some species and lack of enough ground to breed and find mates)
They also have high endemicity
What is carrying capacity?
This is the total number of individuals or organisms there is room for. That is that is the maximum number of individuals there can be.
