Transcript California Science Content Standards

California Science Content Standards
Today's lecture and activity will cover the
following content standards:
5d) Students know different kinds of organisms may play
similar ecological roles in similar biomes. (Grade 6)
5e) Students know the number and types of organisms an
ecosystem can support depends on the resources available
and on abiotic factors, such as quantities of light and water,
a range of temperatures, and soil composition (Grade 6)
7b) Select and use appropriate tools and technology
(including calculators, computers, balances, spring scales,
microscopes, and binoculars) to perform tests, collect
data, and display data. (Grade 6)
California Science Content Standards
Today’s lecture and activity will cover the
following content standards:
7c) Construct appropriate graphs from data and develop
qualitative statements about the relationships between
variables. (Grade 6)
6a) Students know biodiversity is the sum total of different
kinds of organisms and is affected by alterations of
habitats. (Grades 9-12)
Communities, Ecosystems and Biomes
Community: all the populations in a specific
area or region. Studies of communities
include examining interactions between
different species
Ecosystem: refers to the biological
community and the associated abiotic
environment.
Biomes
Def: major regional complex of plant (and
animal) communities; largest scale
community types
Are identified by climax vegetation, which is
influenced by temperature and rainfall
Distribution of Biomes
Within communities, ecosystems and biomes,
scientists are concerned with studying:
BIODIVERSITY
What is Biodiversity?
def: biodiversity = biological diversity =
the variety of life and their habitats
There are three components:
Genetic
Diversity
Habitat
Diversity
Species
Diversity
Losses in Biodiversity
Past extinction rates = 2-25 spp./yr.
Current extinction rates = up to 10,000+
spp./yr.
* past extinctions due to natural phenomena
* present extinctions due to human-caused
phenomena
Genetic Diversity
Def: amount of genetic variation present:
* within individuals
* between individuals within a population
* between populations
Habitat Diversity
Def: variety of ecosystems in an area
Includes:
* communities
* functional properties
*physical properties
Species Diversity
Def: the variety of species in an area
Two subcomponents: species richness
species evenness
Species Richness vs. Evenness
Species Richness: measurement of the
number of species in a given area
Species Evenness: measurement of how
evenly distributed organisms are among
species
Community A
species
species
species
species
species
1
2
3
4
5
25
0
25
25
25
Community B
1
1
1
1
96
Determining Species Diversity
Scientists may want to:
* get an estimate of # of species in an area
* compare species diversity of two
communities
To be accurate, need to:
* take both species evenness and species
richness into account
Species Diversity Indices
Shannon-Weiner (Shannon-Weaver) Index
Diversity =
(p spp 1 - ln(p spp 1)) + (p spp 2 - ln(p spp. 2) + …
(p spp N - ln(p spp. N)
Simpson Index
Diversity =
1
(pspp1)2 + (pspp2)2 + … (psppN)2
Why should we care about
measuring biodiversity
(species diversity)?
Biodiversity Factoids
~ 2,000,000 spp. have been described
~ 10-30,000,000 species actually exist (est.)
~ 8,000,000 – 22,000,000 spp. unidentified
~ 40 – 60% of all spp. occur in two areas:
* tropical rainforests
* coral reefs
Losses in Biodiversity
Past extinction rates = 2-25 spp./yr.
Current extinction rates = up to 10,000+
spp./yr.
* past extinctions due to natural phenomena
* present extinctions due to human-caused
phenomena
Human-Caused Factors
of Biodiversity Loss
Loss of biodiversity caused by:
Habitat Destruction
Introduction of
Exotic Species
Human-Caused Factors
of Biodiversity Loss
Biodiversity loss caused by:
Pollution
Overharvesting/
Overhunting
Extinction
There have been 5 mass extinction events
during the history of the earth
Are we on the verge of a 6th?