Download Chapter 17 Microevolution Designer Pets The many varieties or

Chapter 17 Microevolution
Designer Pets
The many varieties or breeds have been produced through __________________________________ by
humans
Some _______________________ would have been selected against by nature had it not been for human
protection
The Great Chain of Being
Many of the ancient Greeks, including ____________________________, attempted to explain the natural
world by making direct observable
By the 14th century, the ancient view of gradual levels of organization from lifeless matter to the most complex
organisms had been formalized into the _________________________________
The chain extended from lowest level forms to ________________________
Each being (species) had its fixed place in the __________________________—unchanged and unchanging
since creation
Biogeography:
Questions from Biogeography
During the global voyages of the 16th century scientist asked the following questions:
Where do all these species “______________” into the great “Chain”?
Why were certain species found in only some parts of the________________but not others?
How did so many species get from the center of creation to __________________and
_________________________________?
Comparative Morphology
Studies of the _________________________________ of seemingly unrelated animals led to questions of why
certain structures should be so similar
Example: _________________________ in snakes and ______________________ in humans
Questions about Fossils
Studies of ____________________ beds revealed that deposits had been laid down slowly, one above the other
Fossils:
The arrangement of the layers suggested that different ________________________ had lived at different
________________________
De Buffon’s explanation:
New Evidence into Old Beliefs
Georges Cuvier believed in an ________________________ of all species
Cuvier suggested that the abrupt changes in the fossil record in different rock strata reflected the concept of
______________________________
After each catastrophe, ______________________________.
The __________________________ were not new species, it was just that their ancestors’ fossils had not been
found
Lamarck
Theory of acquired characteristics is
Example:
___________________________________ could not uphold his thoughts on acquired traits
Larmarck’s and Darwin
&Wallace’s View
_________________________________is the father of evolution
Voyage on the Beagle
Darwin traveled on the _________________________ for five years as ______________________.
He collected and studied variety of _____________________________
While on the trip he read Lyell’s book ______________________, which proposed the theory of uniformity –
Thus, the earth was________________________ of years old and not thousands of years – evidence of
Evolution
Darwin’s theory takes form
Darwin returned after five years at sea and began pondering the “species problem” what could explain the
remarkable diversity among organisms?
In Argentina, Darwin had observed extinct _________________________that bore suspicious resemblance to
living armadillos; Darwin wondered if the present species had evolved from the extinct one?
Variations in Traits
_________________________ had suggested that as a population outgrows its resources, its members must
compete for what is available.
Darwin felt that if some normally variant members of a population bore ____________________ that increased
their survival, then ________________ would select those same individuals to
______________________________, and possibly change future populations traits.
On the _______________________, the dozen or so species of finches all varied from one another to some
extent but resembled the mainland _________________________ to some degree also; perhaps they had
descended from _______________________
Darwin’s Finches
1) Finches on the ____________________ resembled a mainland finch but there were more types.
2) Galápagos finch species varied by________________________________
3) One unusual finch used a twig or thorn to pry out insects, a job normally done by (missing) woodpeckers
(Darwin never witnessed this finch behavior).
4) The variation in finches posed questions to Darwin: did they ___________________________ from one
mainland ancestor or did islands allow isolated populations to evolve independently, and could present-day
species have resulted from changes occurring in each isolated population?
Example of Darwin’s Finches
Darwin reasoned that a population is evolving when it __________________________ are changing through
successive generations.
1858, Darwin received a paper from ______________________, who had developed much the same theory on
natural selection but independently of Darwin
Darwin and Wallace presented a joint paper but ____________________ published (alone) his ideas in book
form in 1859
Individuals don’t evolve –Populations do
___________________________ evolve, not individuals
A population is
A population exhibits variation among the individual members, but they also hold certain
__________________________________________ traits in common.
The Gene Pool
Individuals of the same __________________ generally have the same number and kinds of
__________________
All of the genes in the entire population constitute the _______________________
Each gene exists in two or more slightly different molecular forms called __________________, which offspring
inherit and express as___________________________
Each particular mix of alleles depend on these five factors:
o
o
o
o
o
__________________________ create new alleles
________________________ and _____________________ are normal results of meiosis
_____________________________ of chromosomes occur in meiosis
___________________________between genetically varied gametes produces “new” combinations of
genes
Abnormal changes in ____________________________ or number can occur.
Stability and Change in Allele Frequencies
______________________________ are a measure of the abundance of each kind of allele in the entire in the
entire population
Evolution can be detected by a change in allele frequencies from the genetic equilibrium as established by the
_______________________________
Hardy Weinberg have five conditions for a Stable population
Because of these five conditions are rarely fulfilled in natural populations, any derivation from the reference
point established by the “________________________” will indicate _______________________
Microevolution:
Mutation Revisited
Mutations
Mutations are random and the ___________________________ outcome may be neutral, beneficial, harmful,
or even lethal to the individual depending on other interactions
Mutations are the only source of new_________________ – the genetic foundation for biological diversity
Three Types of Mutations
Lethal Mutations:
Neutral Mutations:
Beneficial Mutations:
Read Section 17.5 on your own about the Hardy-Weinberg
Natural Selection Revisited
_______________________________ probably accounts for more changes in allele frequencies than any other
microevolutionary process
Major Points to Natural Selection
Observation: All _____________________have the ___________________________ to increase in numbers
over generation
Observation: No population is able to _____________________, for its individuals will run out of
_______________________________________
Inference: Because more individuals are produced than can survive to ____________________________, the
members of a population must compete for the available _____________________
Observation: All the individuals have the same genes, which represent a ______________________ of heritable
information
Observation: Most genes occur in different molecular forms (__________________), which give rise to
differences in _____________________________details
Inferences: Because adaptive traits promote ______________________, they must increase frequency over the
generation and less adaptive traits must decrease in frequency or disappear
Conclusions:
Natural Selection: Adaptation
Adaptation:
Organisms that are adapted to their environment will have the ability to ____________________.
___________________________occurs when an organisms is not adapted to their environment and will not be
able to reproduce
Organisms have Variations
Variations that make adaptation possible are those that are passed on from _____________________ to
________________________.
Darwin could not state the cause of variations because___________________ was not yet established.
Organisms struggle for existence
________________________proposed that human populations outgrow food supply and death and famine
were inevitable.
Darwin applied this to ______________________; resources were not sufficient for all members to survive.
Therefore, there is a constant struggle for existence; only certain members
________________________________.
Organisms Differ in Fitness
1. Organisms whose traits enable them to _______________________ to a greater degree have a
greater_____________________.
2. Darwin noted that humans carry out _________________________.
a. Early humans likely selected wolf variants; produced the varieties of domestic dogs.
b. Many crop plant varieties can be traced to a _______________________________.
d. Evolution by artificial or natural selection occurs when more __________ organisms reproduce and leave
more _____________________
On the Origin of Species
Darwin’s publish book:
It waited 20 years to publish his book
He used this time to complete experiments to prove his _________________________
What is Directional Selection?
___________________________in a consistent direction
Shifts may be in response to environmental pressures or occur as a new mutation appears and proved adaptive
Examples:
Stablizing Selection
Favors the most ________________________ in the population
It counters the effects of _________________________________________
Disruptive Selection
Favors forms at the _______________________________________________ of variation and selects against
the intermediate forms
Sexual Selection
Most species have distinctively male and female phenotypes – _____________________________________
Sexual selection
Usually it is the _______________________ that are the agents of selection when they pick their mates
Maintaining two or more alleles
A________________________________ on the stabilizing theme in which two or more forms of a trait are
maintained in fairly stable proportions depending on survival value in the environment
Population is in ____________________ when nonidentical alleles for a trait are being maintained at
frequencies __________________________
Sickle Cell Anemia
Humans that are ________________________for sickle-cell anemia develop the disease and die at early age
BUT
Individuals with alleles for both normal hemoglobin and sickle-cell hemoglobin (Heterozygous) have the
greatest chances of surviving ________________________
Gene Flow
Genes move with individuals when they move out of (________________________), or into
(___________________________), a population
The physical flow (a result of ____________________________________) tends to minimize genetic variation
between population
Genetic Drift
Is the random fluctuation in _____________________________over time, due to chance occurrences alone
Affects: _______________________________
Bottleneck and Founder Effects
Bottleneck:
Founder Effect:
Genetic Drift