Transcript darwin natural selection & evolution powerpoint 2013

I. History
A. Original ideas:
1. Species are fixed/permanent
2. Earth is less than 10,000 years old
and relatively unchanging
B. Early Scientists
1. Georges Buffon (mid-1700s) French naturalist
a. Suggested Earth might be a lot older than a few
thousand years
b. Specific fossils & certain living
animals were similar but
not exactly alike
B. Scientists
2. Jean-Baptiste Lamarck (mid-1800s)
a. Proposed that life evolves/changes
b. Explained evolution as a process of
adaptation
c. Proposed that by using or not using a
body part, an organism develops
certain acquired characteristics**thought these could be passed on
to offspring**
d. Called “Inheritance of Acquired
Characteristics”
Lamarck’s Giraffe
B. Scientists
3. James Hutton (1700s)
A. Two conclusions:
i. Slow processes from mountain building &
erosion suggest Earth is very old
ii. Slow/gradual change occurring over vast
amounts of time cause enormous change
on Earth
4. Charles Lyell (mid-1800s)
A. wrote influential book Principles of Geology;
B. proposed that gradual and observable
geologic processes such as erosion could
explain the physical features of today's Earth
About 180 million years
ago, Pangaea split into
northern and southern land
masses that later separated
into the modern continents.
India collided with Eurasia
just 40–50 million years
ago, forming the Himalaya
mountain range. The
continents continue to drift
today.
B. Scientists
5. Thomas Malthus
(mid-1700 to mid-1800s)
A. Reasoned that if human
population growth was left
unchecked, sooner or later there
would be insufficient living space for
everyone and we would bring on our own
population control
C. Charles Darwin
1. Mission:
to study the geology, plants, animals he
encountered on his voyage; H.M.S. Beagle; focused
on the Galapagos Islands
2. Observations:
a. too many organisms are
produced
b. All individuals in a species have
variation
c. All individuals must struggle for
existence, and those with favorable
variation have an advantage over
others (fight for food, mate, habitat,
etc.)
d. Variation is heritable time produce
new species.
e. Successive inheritance of favorable variation over vast
stretches of geological time produce new species.
C. Charles Darwin
3. His Main Points:
A. Descent with modificationorganisms spread
out over millions of years and
accumulate different modifications
to diverse ways of life
B. Theory of Natural Selection- process by
which individuals with inherited characteristics
well-suited for their environment survive to leave
more offspring on average than other individuals;
“Survival of the fittest”
WHAT DOES IT MEAN “THE FITTEST”?
Honey Badger
Butterfly
Sea Slug
Glaucus atlanticus
Nudibranchs
Red Squirrel
Dogs vs. Wolves
Water Bears
Venezuelan Pitcher Plant
Hemeroplanes
triptolemus
moth
Glasswing Butterfly
Camel
Descent with
Modification
Survival of
the fittest
D. Alfred Wallace (1858)
Came to same conclusion as Charles
Darwin, sent Darwin his manuscript.
Darwin published his book, On the Origin
of Species, in 1859.
Why didn’t he publish sooner?
EVOLUTION
II. Evolution
Define “evolution”:
gradual changes that have transformed
life over an immense period of time
A. Evidence of Evolution
1. Fossil record
2. Geographic Distribution- continental drift
3. Similarities in structures
4. Similarities in development
5. Molecular biology- DNA, proteins
B. Fossil Record
1. A fossil is preserved remains or markings left
by organisms that lived in the past
2. Fossils are cast in sedimentary rock
Imprint
Mineralized
Frozen
Amber
Cast
THE FOSSIL RECORD
3. Dating Fossils
i. Radiometric Age
- Measurement of
isotopes in objects
ii. Relative Age
- Age based on
layers
C. Geographic Isolation
1. Traits of organisms are directly linked to the
geography and environmental conditions of
an area
D. Homologous Structures
1. Homologous Structures: different organisms
that have similar bone structure
2.
E. Analogous Structures
1.
Define: features of different species that are similar in
function but not in structure- are not derived from a
common ancestor, but evolved in response to similar
environmental challenge.
Examples
2. Example: Insects and birds both have wings to fly,
although their wing structure is very different structure.
The fat-insulated, streamline shapes of seals
(mammals) and of penguins (birds) is another example.
F. Vestigial Structures
1. Vestigial Structures- remnants of
structures that may have had important
functions in an ancestral species but have no
function currently
G. Similarities in Development
1. Embryos of closely related organisms
have similar stages in development
H. Molecular Biology
1. Similar DNA suggests an evolutionary relationship
2. Hemoglobin
3. Cytochrome C
III. OTHER CONCEPTS IN
EVOLUTION
A. Antibiotic- and Pesticide-Resistance
1. Antibiotic- medicine that kills/slows the
growth of bacteria
2. Some bacteria with natural resistance will
not be killed off by the antibiotics and can
re-grow a resistant population quickly
3. When pesticides are used, some insects will
already have a natural resistance and survive
the spraying, then reproduce more insects that
inherit the resistance genes. Eventually the
same pesticides will not have the same effect as
before.
B. Artificial Selection
1. Define: selective breeding
of domesticated plants
and animals to produce
offspring with genetic
traits that humans value
IV. Types of Evolution
A. Divergent Evolution: consequence of
adaptive radiation- organisms sharing
a common ancestor evolve to become
different according to environmental
pressures
Adaptive Radiation
B. Convergent evolution: arises when there are
some sort of ecological or physical driver
toward a similar solution, even though the
structure or function has arisen
independently.
Ex: sharks and dolphins share
analogous body plans, yet have
different ancestral backgrounds
(fish versus mammal)