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Evolution and Biodiversity
I.
Types and Origins of Life
A. Major types of life on earth
1.
_______________ are the basis of life on earth
2.
Two major kinds of cells
a. prokaryotic—no nucleus, primitive, bacteria
b. eukaryotic—nucleus and internal structures
3.
Classification/Taxonomy
a.
Kingdom….
b.
other taxonomic groups
c.
scientific names: the only ones that count
Format and examples
4.
species—
B. How did life emerge on the primitive earth?
1.
a billion years of chemical evolution
2.
3.7 billion years of biological evolution, Fig 5-2
C. How do we know what was here in the past? Fig 5-3
1.
2.
3.
4.
II.
Evolution and Adaptation
A. What is evolution? a change in the genetic makeup of a ____________________ through
successive generations.
B. How does evolution work?
1.
Genetic information is carried in the sequences of the ________________ in
____________. _______________ are sequences of DNA that code for traits.
They are heritable, which means they can be passed on to offspring. A
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population’s collection of genes is called a _____________________.
Different forms of a gene are called ___________________, which are
randomly shuffled during ____________________. The key ingredient that
allows evolution to occur is __________________________.
2.
4 important things in evolution
a.
mutation— a random change in the DNA structure of an INDIVIDUAL
They are caused certain chemicals and energies called
__________________. Mutations are ______________,
_______________, and are almost always _______________.
b.
gene flow—allows genes to move between populations
c.
genetic drift—random changes in gene frequency in small populations
d.
Natural selection—occurs when traits enable SOME INDIVIDUALS to
survive and produce more offspring
1. requires…
2. requires…
3. reproductive advantage, a.k.a. differential reproduction occurs,
which is the ability to…
4. then, advantageous alleles increase in frequency in successive
populations
5. selective pressure—environmental conditions that lead to the
possibility of mutations being beneficial. A beneficial mutation is
called an….
3.
4.
Types of natural selection
a. directional: “it pays to be ____________________” –environmental
conditions lead to allele frequencies at one end of the range of
variability to become more prevalent. Exemplified by the peppered
moth; modern day antibiotic resistance; giraffes
b.
Stabilizing: “it pays to be ____________________”—eliminates
individuals on the extremes of variability
c.
Diversifying/disruptive—“it doesn’t pay to be _________________”—
extremes are favored and the average is eliminated
To summarize: Genes mutate and create a characteristic that may be
beneficial. Individuals with this adaptation are selected, so the gene that codes
for that trait increases in the population.
C. Coevolution—when different species evolve together based on each other’s adaptations
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III.
Adaptation and the Niche
A. What’s a niche and how do you pronounce it? (“What’s up, my…”)
1.
2.
vs habitat: Where you live vs what you do
3.
fundamental vs realized: You’ve been lied to.
B. Generalists and Specialists
1.
generalist—
2.
specialist—
3.
which is better? It depends
C. Convergent evolution—because similar ecosystems present similar selective pressures,
similarities are observed between different taxonomic groups. For example:
D. Limits to adaptation: you’ll never be perfect (sorry)
IV.
1.
you can only have adaptations for a trait already in the gene pool
2.
adaptations are often compromises
3.
you have a limited reproductive capacity
4.
other individuals w/o the trait also reproduce
Speciation, Extinction, and Biodiversity
A. speciation—when natural selection leads to the development of two species from one
B. Typically occurs in two steps, particularly in animals
geographic isolation….reproductive isolation….now natural selection can lead to two
new species = divergent evolution
C. Extinction: when a species is ____________________ lost
1.
How many?
2.
background extinction
3.
It does, however, create opportunity. After an extinction, there is a rapid
evolution of numerous new species to fill the void created by mass extinctions
and depletions. This is called:
vs
mass depletion
D. Both speciation and extinction are affected by
1.
vs
mass extinction
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2.
3.
E. Modern day
F.
1.
B=S–E
2.
What are the projections of Wilson and Primm?
Evolutionary misconceptions
1.
2.
3.
V.
The future of evolution: how have humans impacted evolution?
A. Artificial selection: pit bulls and purple carrots
B. Genetic engineering: fish genes in a tomato?
Inserting genes from one organism into the genes of another produces as genetically
modified organism (GMO), or transgenic, organism. This saves time, but can produces
unintended consequences. Some say we are “playing God”. It creates controversy:
Miracle or Menace?
VI.
Biodiversity and it’s importance
A. Biodiversity
1.
2.
3.
4.
variety of genes in a population:
variety of species present (richness):
variety of ecosystems:
variety of roles in an ecosystem:
B. Importance:
1.
generally, more biodiversity = more resistance to disturbance, catastrophe, etc.
( in other words, more ____________________)
2.
Greater biodiversity provides us with better resources of food, wood, fiber,
energy, medicines, clean air, clean water, fertile soils, , and pest control.