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CONSERVATION AND BIODIVERSITY
4.1 Biodiversity in ecosystems
Assessment Statements
4.1.1 Define the terms biodiversity, genetic diversity, species diversity, and habitat diversity
4.1.2 Outline the mechanism of natural selection as a possible driving force for speciation.
4.1.3 State that isolation can lead to different species being produced that are unable to interbreed to yield fertile offspring.
4.1.4 Explain how plate activity has influenced evolution and biodiversity.
4.1.5 Explain the relationships among ecosystem stability, diversity, succession and habitat.
4.1.1 Define the terms biodiversity, genetic diversity, species diversity, and habitat diversity
Biodiversity: amount of biological or living diversity per unit area. Consists of species, habitat, and genetic diversity
Genetic Diversity: Different genetic characteristics of a species.
Cheetah populations have very low diversity, due to inbreeding
4.1.1 Define the terms biodiversity, genetic diversity, species diversity, and habitat diversity
Species diversity – the variety of species per unit area; includes the number of species present and their relative abundance.
4.1.1 Define the terms biodiversity, genetic diversity, species diversity, and habitat diversity
Habitat Diversity: The amount of habitats or niches in a given area Variety of forests, deserts, grasslands,
lakes, oceans, coral reefs, wet lands, and other biological communities.
Chaparral Coniferous forest dessert grasslands deciduous forest
Biodiversity: Why should we care?
Diverse ecosystems are more stable and more healthy
More resistant to damage from factors like climate change and spread of disease
Provides important ecological services to humans
Biodiversity is useful to us as humans Recreation Food Goods Medicine
Ecological Services of Biodiversity
Flow of material, energy in the biosphere Photosynthesis Pollination Soil formation and
maintenance Nutrient cycling Moderation of weather
extremes Purification of air and
water
Important “stuff” From biodiversity Food, fuel, ecosystems, species, fiber,
lumber, paper…. 90% of all food crops 40% of all medicines and 85% of all
antibiotics
Pacific Yew – Taxol (cancer drug)
Willow Tree - Aspirin
Biodiversity of Species
Each Species and Process…
Is key to the overall function of earth In general Diversity = Stability Biodiversity is
Nature’s insurance policy against change The source of all natural capital for human
use The way chemical materials are cycled and
purified The end result of millions of years of
evolution and irreplaceable
Mexico
Brazil
Madagascar
South Africa
Australia
Indonesia
Philippines
India
China
EcuadorColombia
Costa Rica
Peru
Venezuela
CameroonZaire
Ethiopia
Myanmar
Malaysia
The 19 Most Biodiverse countries in the world.What is the Problem with this?
Polynesia andMicronesia
islandcomplex
Mediterraneanbasin
Caribbean
WesternGhats andSri Lanka
Philippines
Wallacea
NewCaledonia
TropicalAndes
CentralChile
BrazillianCerrado
Caucasus
Eastern Arc Mountainsand coastal forests
of Kenya and Tanzania
Cape Floristicregion of
South Africa
SucculentKaroo
Madagascar/Indian Ocean
islandsSouthwestAustralia
New Zealand
Polynesiaand
Micronesiaisland
complexIndo-Burma
Mountains of southcentral China
Guineanforests of
WestAfrica
Brazil'sAtlanticforests
Sundaland
Choco/Darien/western Ecuador
CaliforniaFloristicProvince
Meso-americanforests
Biodiversity Hotspots need special consideration
Hotspots
These areas need emergency conservation attention
Especially rich in endemic plant and animal species (found nowhere else in the world)
They cover on 1.4% of world land area Mostly tropical forests Contain 60% of identified terrestrial biodiversity 55% of all primates, 22% of all carnivores 1.1 billion people living in poverty near these
sites $500 million annually would go far to ensure
their preservation
Diversity includes
1. Richness: The number of species per sample is a measure of richness.
The more species present in a sample, the “richer” the sample.
2. Evenness: A measure of the relative abundance of the different species making up the richness of an area.
Which sample is more diverse?Flower Species Sample 1 Sample 2
Daisy 300 20
Dandelion 335 49
Buttercup 365 931
Total 1000 1000
Which has a higher richness? Evenness?
Quantifiying this Diversity – Simpson’s Index
D = N (N – 1)∑ n (n – 1)
Where D = diversity index N = total # of organisms of all species n = # of individuals of particular
species
Now practice the simpson’s index
Species Number (n) n (n – 1)
Woodrush 2
Holly seedlings 8
Bramble 1
Yorkshire Fog 1
Sedge 3
Total (N)
Now practice the simpson’s index
Species Number (n) n (n – 1)
Woodrush 2
Holly seedlings 8
Bramble 1
Yorkshire Fog 1
Sedge 3
Total (N) 15
Now practice the simpson’s index
Species Number (n) n (n – 1)
Woodrush 2 2
Holly seedlings 8 56
Bramble 1 0
Yorkshire Fog 1 0
Sedge 3 6
Total (N) 15 64
15(14) / 64 =3.28
High values of “D” suggests a stable and ancient site
A low value of “D” could suggest pollution, recent colonization, or agricultural management
Index normally used in studies of vegetation but can be applied to comparisons of diversity of any species
How does diversity exist?
Natural Selection = survival of the fittest Fitness = a measure of reproductive success
If all individuals are variable And populations produce large numbers of
offspring without increase in population size And resources are limited And traits are heritable
How does diversity exist?
Those individuals who are best adapted to the environment will survive and pass on their genes
Gradually the gene frequency in the population will represent more of these “fit” individuals