3.1 An introduction to biodivesrity Flashcards
Define biodiveristy Importante amiga
Biodiversityis the variety of all life onearth. Itincludesgenetic diversity, species diversity and habitat diversity.
What biomes have higher biodiversity?
- Tropical rainforest biomes are some of the most diverse terrestrial ecosystems on the planet,
- Hot and cold deserts are some of the most sparse
How does biodiversity change by latitude?
The highest biodiversity is around the equator and the tropics, while there is much lower diversity towards the poles
What does the equator provide for the ecosystems near it?
Good climate, presipitation, insolation, good temperature
Therefore: there is more primary productivity and thus more plant growth
➕plant growth = ➕ vegetation = ➕habitats = ➕food, water shelter = thus less competition = ➕species diveristy = ➕genetic diversity
Name an actual area of rainforest
Amazonia
Factors (aside from latitude) that affect biodiversity
- Age of the area (stage of succession)
- Range of habitats
How is a different range of habitats created? (HINT: 4)
- Greater vertical extent of the vegetation: forests versusgrasslands, because forests are layered they offer a wider range of habitats.
- Altitudinal variation: any area with a mountain range will have a range of climates associated with the different heights and so different organisms in each zone.
- Latitudinal ranges: areas that extend across the latitudes will have the same sort of variation as seen in mountain ranges.
- Variation in rock and soil types: changes in theabioticenvironment will cause changes in the biotic environment so increasing biodiversity.
Define species diveristy
Species diversityis the number of different species in a given area taking into account the richness and evenness of the species
What is richness? (in relation to species diveristy)
Richnessis a measure of the number of different species in an area; more species means a richer environment
Why is richness alone to asess species diversity lacking?
- No account is taken of how common or rare each species is.
- Using richness alone to assess diversity can be inaccurate as species need to reproduce to maintain their presence in the ecosystem
What is eveness?
Evennesslooks at the relative abundance of the species.
MORE EVEN= MORE DIVERSE
Simpsons diversity index FORMULA:
D=N (N−1) / ∑n(n−1)
(Te la dan en el examen pero tienes que saber qué es cada letra)
D=N(N−1)/∑n(n−1)
Where:
- D is the Simpson Diversity Index.
- N is the total number of organisms of all species found.
- n is the number of individuals of a particular species.
Why are diversity index’s useful?
A diversity index allows us to put a mathematical value on the diversity of a community, which in turn allows us to compare communities over time or space
Define Genetic Diveristy (HINT: Key term “genetic pool”
Genetic diversity refers to the variation of genes within the genetic pool of a population of a species
Give 3 reasons why genetic diversity is I M P O R T A N T (hay 5 reasons pero con 3 mas que sufi)
- There is a better chance thatsome members of the species will be resilient and surviveenvironmental change.
- Low genetic diversity (often caused by small populations) causes inbreeding which makesthe genetic make-up of the populationmore uniform. → disabilities within that population will become more common.
- Extinction is frequently preceded by a drop in genetic diversity.
- Once lost, genetic diversity is almost impossible to regain.
- If something we rely on (such as wheat) is struck by disease then genetic diversity increases the chances of us finding alternatives to that are disease free.
