Unit 3 Flashcards
Biodiversity
Is the variety of all life on earth.
Includes genetic diversity, species diversity and habitat diversity.
Factors that affect biodiversity and benefits of biodiversity
Age of area - older areas - higher biodiversity
Environmental stability - earthuaks disturbances
Range of habitats
Benefits
- financial benefits
- invaluable services
- playgroud
-educational opportunities
Species diversity
is the number of different species in a given area taking into account the richness and evenness of the species.
Species diversity in communities is a product of two variables: the number of
species (richness) and their relative proportions (evenness).
Simpson Diversity Index formula and ca
D is the Simpson Diversity Index
N total number of organisms found
n is the number of individuals of a particular species
What does the Simposon Diversity Index allow?
Puts a mathematical value on the diversity of a community which allows comparison of communities over time and space
Genetic diversity and importance
Refers to the variation of genes within the genetic pool of a population of a species it is the means by which that population can adapt to change.
IMP
- Better chance members are reciliense and survive to disease
- Low genetic diversity makes the population more uniform and amplidies disabilities
- frequent extinction
- once lost GD difficult to regain
- wy rely on species for medicine, food..
Habitat diversity
The range of different habitats in an area.
Terrestial biomes - most important abiotic environment for plants: temperature, soil type, precipitation.. A variety of vegetation in an area results in a grater diversity of animals
Marine habitats - transient and changable an abiotcic factors incluse dissolved gasses, land runofff, marine topography, nutrients, salinity, pH, sunlight, temp
Links between habitat diversity, genetic diversity and species divesity
- High habitat diversity = more areas for populations –> greater variation of gene pool
- High habitat diversity = wide range of spaces for animals to adapt –> High species diversity
- High genetic diversity = increased adaptability of species –> higher species biodiversity
- High species diversity of plants –> higher habitat diversity
Evolution
is a gradual change in the genetic character of populations over many generations, achieved largely through the mechanism of natural selection.
Environmental change gives new challenges to species, which drives the evolution of diversity.
There have been major mass extinction events in the geological past.
Causes of evolution
Process of genetic variation
- Mutations (change in DNA) may be beneficial, harmful, neutral
- Natural selection - the gene variatons has survival advantages
Speciation
is the formation of a new species through biological processes.
Relationship between speciation and diversity
Evolution drives speciation and it is commonly dirved by isolation
- Geographic isolation: Populations are physically separated and can no longer interbreed
- Temporal isolation: Populations live their lives at different times of the day and so do not meet to breed.
- Behavioural isolation: They have different mating rituals.
Natural selection occurs through the following mechanism
Within a population of one species, there is genetic diversity, which is called variation.
Due to natural variation (range of genetic diversity). some individuals will be fitter than others.
Fitter individuals have an advantage and will reproduce more succesfully than individuals who are less fit
The offspring of fitter individuals may inherit the genes that give that advantage
Plate techtonics theory
The theory explains the motion of the earth’s lithosphere (outer layer) and the impact that has had on the distribution of the continents
Plate movement has a significant impact on evolution and creates opportunities for biodiversity
The separation and movement of the continents creates new islands and moves the continents into different climatic zones forcing evolutionary change.
The movement creates four types of plate boundaries each associated with different types of activity with varying impacts on biodiversity.
Hotspots and other volcanic activity create new land.
Endemic species
is unique to a particular location and not found elsewhere.
It is important that you understand and are able to explain how climatic variation impacts evolution through natural selection and thus biodiversity.
different areas of the world have very different climates, caused largely by their latitudinal positions.
The only organisms that can survive in an area are those that have evolved and adapted to the temperature, precipitation, and sunlight levels and the seasonal patterns they all show.
So a wide range of climatic zones means evolutionary adaptation and a wide range of organisms = MORE BIODIVERSITY
The range of climates seen on Earth provide diverse habitats, niches and food sources, all of which contribute to evolution through natural selection high biodiversity.
Plate boundaries
Three types
Divergent and convergent have both significant positive and negative impacts on biodiversity.
Convergent: Move together create mountains, volcanoes, land bridges, ocean trenches
divergent: Move apart and create opp for diversificaton