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Biodiversity & Evolution
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Biodiversity & Evolution
Chapter 4
BIODIVERSITY
Biological diversity is the variety of the earth's species, the genes they contain, the ecosystems in which they live, and the ecosystem processes such as energy flow & nutrient cycling that sustain all life.
Evolution
Genes Mutate
EVOLUTION
Biological Evolution is the process whereby earth's life changes over time through changes in the genes of populations.
Individuals are Selected
Populations Evolve
History
Evidence
What do scientists use to study evolution?
- Fossil Record
- Transitional species
- Why will the fossil record probably never be "complete"
- Comparative Anatomy
- Homologous & analogous structures
- Embryological comparision
- Vestigial structures
- Genetic Comparison
- DNA
- RNA
- Amino Acids
Mechanisms
Natural Selection
Occurs when some individuals of a population have genetically based traits that enhance their ability to survive and produce offspring with the same traits.
AP Exam readers will assume that you do not know what this means.
SURVIVAL
OF THE
FITTEST
Types of Natural Selection
Sexual Selection
Artificial Selection
What Affects Evolution?
Geologic Processes
- Tectonic Plate Movement
- Earthquakes
- Volcanic Eruptions
Climate Change & Catastrophes
- Ice ages followed by warming temperatures
- Asteroid collisions
- Trapped methane releases
Speciation
Speciation-
Process through which two species arise from one.
Geographic isolation can lead to reproductive isolation.
Extinction
EXTINCTION
Process that affects the number and types of species on the earth.
Process in which an entire species ceases to exist.
Endemic species: species found in only one area and are vulnerable to extinction.
Types of Extinction
Types of Extinction
What causes extinctions to occur?
01.
Background Extinction:
- Low rate extinction
- 1-5 species for each million species per year
02.
Mass Extinction:
- High rate extinction
- Large groups of species above the background rate
Species Diversity
- Species Richness:
number of different species
- Species Evenness:
relative abundance of individuals within each of those species
SPECIES DIVERSITY
Calculating Species Diversity
Shannon Diversity Index
Used for species diversity index
H'
E
=
H
Used for species evenness index
Max
Trends of Species Diversity
- Latitudinal Species Gradient
- Elevation
- Precipitation
Roles of Species
Ecological Niche
A species role in a community that takes into account everything that affects its survivial & reproduction.
Generalist Species vs. Specialist Species
Native Species vs. Nonnative Species
Competitive Exclusion Princliple
Indicator Species
Keystone Species
Foundation Species
CASE STUDIES
For each of the case studies, identify what type of species they are and their ecosystem niche.