Download Powerpoint

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Population genetics wikipedia, lookup

Paleontology wikipedia, lookup

Evolutionary history of life wikipedia, lookup

Genetic drift wikipedia, lookup

Introduction to evolution wikipedia, lookup

Theistic evolution wikipedia, lookup

Saltation (biology) wikipedia, lookup

Hologenome theory of evolution wikipedia, lookup

Natural selection wikipedia, lookup

The Selfish Gene wikipedia, lookup

Inclusive fitness wikipedia, lookup

Evolution of sexual reproduction wikipedia, lookup

Evidence of common descent wikipedia, lookup

Sexual selection wikipedia, lookup

Vestigiality wikipedia, lookup

The Descent of Man, and Selection in Relation to Sex wikipedia, lookup

Transcript
The Theory of Natural Selection
Biology I
1
I. Early Biology
• Scientists knew
that organisms had
changed
• Fossil evidence
• Age of the Earth
2
Lamarck
• Changes from simple
to complex
• Organisms want to
adapt or change
• Acquired
characteristics were
inherited (passed on)
3
Lamarck
• Later disproved
4
5
II. Darwin
• At 21, took a job as
a naturalist on the
HMS Beagle
• Collected
specimens, took
notes of different
organisms
6
His voyage:
7
II. Darwin
• Sailed to Galapagos
Islands
• All new species, but
similar to those found
elsewhere
8
• Finches most famous
• Had slightly different beaks from island to island
• Differed by their diet
9
II. Darwin
• Darwin 22 years
developing theory of
natural selection
• Pressured into
publishing by
Wallace
• Published On the
Origin of Species by
Natural Selection
10
III. Natural Selection
4 Requirements
•1. Variation exist
•
2. Differential
Reproduction
•
•
3. Heredity
Best suited survive and
reproduce
4. Lots of Time
11
1. Variation
• Variations exist
– Color, size, speed, etc.
• Variations are genetically
linked
12
2. Differential Reproduction
• Organisms produce more
offspring than can survive
– creates competition and
Survival of the Fittest =
Only the best are going to
survive
13
Heredity
• Beneficial variations
survive, pass traits to
offspring
• Passed through DNA
14
Natural Selection
• Over time variations
become more frequent
in population
• Results in population
being different than
ancestors
15
Evolution
Evolution is the change in a population over time
Natural Selection - Remember the Giraffe?
How did it get the long neck?
16
Evidence of Change
•
•
•
•
Fossil Record
Anatomy & Physiology
Embryology
Biochemistry
17
Fossils
• Remains or traces of living
organisms
18
Physiology
Mimicry-An adaptation
• Enables one species to resemble another
species.
• Ex.-harmless species looks like a harmful
one, good tasting vs. bad tasting.
19
20
21
Camouflage-An adaptation
• A species blends in with its environment to
avoid predators.
• Ex.- peppered moth,
leaf frog
22
Anatomy- Homologous
Structures
• Common evolutionary origin.
Similar in arrangement or function
or both.
• Example: forelimbs of a whale, a
crocodile and a bird wing.
23
24
Anatomy- Analogous Structures
• No common evolutionary origin,
but similar in function.
• Wings of a bat and wings of a
butterfly.
25
26
Anatomy- Vestigial Structures
• No function now but was probably useful to
an ancestor.
• Ex. A whale has leg bones, a snake has leg
bones
27
28
Embryology
• Earliest stage of growth and development
• Embryos of a fish, a chicken, a pig, a cow, a
rabbit, and a human are almost identical.
• They all have gill slits and a tail.
29
30
Biochemistry
• Comparisons of DNA and RNA
• Now monera (prokaryotes) is divided into
two separate kingdoms based on their
biochemistry.
31
V. Mechanisms of Evolution
• Genetic Drift
• Gene Flow
• Artificial Selection
• Natural Selection
Sexual Selection
32
Genetic Drift
• Change in allele
frequency by
CHANCE
33
GENE FLOW
• Bottleneck effect
• Founders effect
34
Gene Flow
• Change in allele frequency as a
result of MIGRATION
35
Sources of Variation
• GENE FLOW moves genes among
populations
• SEXUAL REPRODUCTION
introduces new gene combinations
• Random MUTATIONS in DNA
lead to the formation of new
alleles (sound familiar?)
36
Mutations
• Can be beneficial, neutral, or
harmful for the organism
• Only mutations in gametes are
inherited by offspring
37
Bell:
• What is the difference between Analagous
structures, Homologous Structures, and
Vestigial Structures?
• What are the 4 requirements of Natural
Selection?
AGENDA
•Intro to Classification
•Natural Selection Today
•Antibiotics
38