Download Darwin - Bishop Ireton

UNIT 9
Evolution
Darwin and Evolution
Charles Darwin
 Naturalist
 1809-1882
 Traveled on HMS
Beagle for 5 years
(22 yrs old)
 Galapagos islandsunique animals like
the turtles and
finches found there
 Travel and
observations lead to
Darwin's ideas………
Influences on Darwin
• Hutton: Earth is shaped by geologic forces-older than
millions of years
• Lyell-processes on Earth have been happening for a long
time and these processes have shaped the Earth’s
geologic features
• Lamark-use and disuse,inheritance of aquirred traits
• Malthus-human population will grow faster than raw
materials can be produced
Natural Selection
 Explanation of how populations change over time ( a
very long time)
 Another way to say this:
Survival of the Fittest- those organisms within the
group have some sort of variation that allows them to
survive and produce offspring with the same variation
For all populations these factors must
exist for natural selection:
 Organisms overproduce- more babies born than will
actually survive
 Variations exist within the species- example: fish scale
color
 Variations passed on to offspring
 Overtime the population changes to exhibit the favorable
variations
Artificial selection
• Humans select desired traits
• Dog breeds
• Descent with modification-each living species has
desended with changes from other species over time.
• Common descent-all species derived from common
ancestor
Evidence of Evolution
Seen in:
 Structural changes
a. camouflage- blend into surroundings
b. mimicry- look like another organism with a
favorable trait
 Physiological changes- metabolism
ex. Drug resistant bacteria
Camouflage
Mimicry
We can see the changes by showing
relationships between organisms
1.Fossilsa. molds (left behind by
soft tissue)
b. bones
2. Anatomy-look at structures
a. homologous- similar in arrangement and/or function
b. Analogous – similar in function but not in structure
 C. Vestigial- organ or structure not used any
more like our appendix. Do you know what
animal has a working appendix?
RABBITS
 Other examples:
Molars in vampire bats
leg bones in snakes and whales
ear muscles in humans
 3. Embryology- study
of embryos. Look for
similarities.
 4. Biochemistry-horseshoe crab biochemistry more
similar to spiders than other crabs.
 5. Geographic distribution-similar animals develop in
different areas due to common conditions.
 www.ngm.nationalgeographic.com/ngm/0411/feature1/m
ultimedia/index.html
Population Genetics
 Gene pool- # or % of alleles in a population
 Allelic Frequency- % of a specific allele in a gene pool.
(Ex.- how many B’s or b’s in the classroom)
 Do populations change? YES!!!!
 Genetic Equilibrium- no real change in allelic frequency
of population
Ways a Population Can Change
 Mutation- (in gametes)
 Sexual reproduction
 Genetic Drift- alteration by chance event like an
earthquake, fire, flood-change in allelic frequency
 Gene Flow- movement in or out of organisms in a
population. Ex. All the people with blue eyes moved
to Canada- what would happen to the allelic
frequency of b?
 Traits controlled by a single gene will have a greater
chance of differences in allelic frequency and
therefore lead to change.
3 Types of natural Selection
Which group is favored?
 Middle group- STABALIZING SELECTION
 One extremes- DIRECTIONAL SELECTION
 Both extremes- DISRUPTIVE SELECTION
Hardy –Weinberg Principle
•
1.
2.
3.
4.
5.
In order to maintain genetic equilibrium:
Random mating
Large population
No movement in or out
No mutations
No natural selection
How do new species form?
 Speciation- evolution of a new species-new group is
unable to breed with old group
 Behavioral isolation- wrong mating dance
 Geographic Barrier- splits group and over time changes
occur in one or both groups that do not allow them to
breed with each other.
 Reproductive isolation- 2 groups can’t mate with each
other –parts don’t fit, different mating cycles (Temporal)
How fast does evolution occur?
 Speciation Rate- speed of evolution
 Gradualism- speciation occurs gradually over a long
period of time
 Punctuated- short quick bursts( dinosaurs)
The Classification of Organisms
• Branch of biology that groups and names organisms
based on similarities
• Aristotle started grouping plants into 3 categories:
herbs, shrubs, and trees
• Based his groupings according to physical and structural
characteristics
• Had a 2 word naming system like a first and last name
called
BINOMIAL NOMENCLATURE
• Used Latin because it is universal and it’s a dead
language (it doesn’t change)
• When we name organisms we usually just give the
Genus and species name like
• Homo sapien
• Note that the Genus name is capitalized and the
species name is in lower case
• In print you will see the Genus and species name in
italics.
 Biggest to smallest
(Domain)
Kingdom
Phylum
Class
Order
Family
Genus
Species
Kings play chess on fine green sand
• Structural similarities
• Breeding behavior
• Geographical distribution
• Chromosome comparison (how many bases match)
• Biochemistry
Domains
 Bacteria-prokaryotic, cell wall made of
peptidoglycan,common like strep,staph
Kingdom-Eubacteria
 Archaea-prokaryotic,live in extreme environment
Kingdom- Archaebacteria
 Eukarya- eukaryotic cells
Kingdoms-Protista,Fungi,Plantae,Animalia
Domain Eukarya
Protista-animal like, plant like,
fungi like, most single celled,
some photosynthetic
Fungi- heterotrophs, decomposer
Plantae- multicellular,
photosynthetic, cell wall
Animalia- multicellular,
heterotroph