Download 1 Chapter 16: Evolutionary Theory Section 1: Developing a Theory

Chapter 16: Evolutionary Theory
Section 1: Developing a Theory
Evolution:
Artificial Selection:
Evolution:
I. A Theory to Explain Change Over Time
B. Charles Darwin
1.
2.
C. Theory:
D. Modern evolutionary theory began when Darwin presented evidence
that evolution happens and offered an explanation of how
evolution happens
1. Like most scientific theories this keeps developing and
expanding
2.
II. Darwin’s Ideas from Experience
A. In Darwin’s time most people did not think organisms or the Earth
had changed
B.
C.
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D. The Voyage of the Beagle
1. Darwin collected evidence on a global voyage
a.
b.
c.
2. Galapagos Islands
a. Collected several species of finches
1)
2)
3)
b. Noticed species of plants and animals were similar to what he
found in S. America
1) Determined species on Island were descended from
species that came from S. America
2) Decent with Modification
a) Idea that all finches descended from one ancestral finch
and were changed due to the food they ate
E. Years of Reflection
1.
a. Continued to study his findings and other sciences
F. Breeding and Selection
1. Darwin’s insight
a.
b. If find a specific trait they like they can produce more
individuals that have desirable traits
c. Artificial Selection
1) Process of selecting desirable traits by humans not by
nature
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III. Darwin’s Ideas from Others
A. Darwin was influenced by ideas from numerous fields
1.
2.
3.
B. People who influenced Darwin
1.
2.
3.
4.
C. Lamarckian Inheritance
1.
2. Organisms change over time as they adapt to changing
environments
3. Had incorrect idea
a)
b) i.e. Person’s muscles may decrease or increase in size due to
use or disuse - Lamark thought offspring could inherit this
change
D. Population Growth
1.
2. Food supplies were increasing linearly – number of people was
increasing exponentially
3.
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a. All kinds of populations produce more offspring than can
survive
b.
E. Geology and an Ancient Earth
1. Geology –
2.
3. Cuvier argued that fossils in rock layers showed differences in
species over time
a.
b. Did not see species changing gradually over time thought
changes occurred suddenly
4. Hutton and Lyell geologic processed work gradually and
constantly
a.
Section 2: Applying Darwin’s Ideas
Natural Selection: process by which individuals that are better adapted
to their environment survive and reproduce more successfully than
less well adapted individuals
Adaptation:
Fossil:
Homologous: describes a character that is shared by a group of species
because it is inherited from a common ancestor
I. Evolution by Natural Selection
A.
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B. Natural Selection
1.
2. Evolution is a change in the inherited characteristics of a
population from one generation to the next
C. Steps of Darwin’s Theory
1. Theory of Evolution by Natural Selection
a.
2. Overproduction
a.
3. Variation
a.
b.
4. Selection
a. In given environment, having a particular trait can make
individuals more or less likely to survive and have
successful offspring
b.
5. Adaptation
a.
D. Selection and Adaptation
1. Darwin’s theory explains why living things vary in form yet fit
their environment
2.
3. Each species evolves because of the “selection” of those
individuals that survive
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4.
5.
E. Publication of the Theory
1. Darwin’s Book:
II. What Darwin Explained
A. The Fossil Record
1.
2.
B. Biogeography
1. Study of the locations of organisms around the world
2. Find geography separates populations
a.
C. Developmental Biology
1. Ancestry of organisms evident in ways multicellular organisms
develop from embryos
2. Embryology
a.
D. Anatomy
1.
2. Homologous structures are characteristics that are
E. Biochemistry
1.
2. Evidence of hereditary relationships among species in proteins
and amino acids
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Section 3: Beyond Darwinian Theory
Speciation:
I. Darwin’s Theory Updated
A. Discoveries since Darwin’s time, especially in genetics, have been
added to his theory to explain the evolution of species.
B. Some parts of Darwin’s theory have been modified, and new parts
have been added. But mostly, Darwin’s theory has been
supported.
C.
D. Survival and reproduction can be limited by chance or by the way
that genes work
E. Natural Selection
1.
F. Migration
1.
2. Migration can change the numbers and types of alleles in a
population.
3. Mate Choice
a. Parents are paired up randomly in a population, a
random assortment of traits will be passed on to the
next generation.
b.
G. Mutation
1.
H. Genetic Drift
1.
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2. Some alleles may become more or less common in a
population, especially in a small population.
I. Coevolution
A. Organisms are part of one other’s environment
1.
2. Species that live in close contact often have clear
adaptations to one another’s existence.
J. Adaptive Radiation
A.
1. As this splitting repeats, one species gives rise to new
species
2. The process speeds up when a new species enters
environment that contains few other species
K. Extinction
1.
2.
a. Few of their descendants survived and evolved
into the species present today
L. Graduated Equilibrium
1.
M. Punctuated Equilibrium
1.
2. Species remain stable for long periods until environmental
changes create new pressures
3.
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