Transcript evolution & natural selection powerpoint 2013

I. Darwin
A. Original ideas:
1. Species are fixed/permanent
2. Earth is less than 10,000 years old
and relatively unchanging
B. Early Scientists
1. Suggested Earth might be a lot older than a few
thousand years by looking at specific fossils &
certain living animals were similar but not exactly
alike
• 180 million years ago,
Pangaea split in 2 land
masses
• India collided with Eurasia
just 40–50 million years
ago, forming the Himalaya
mountain range.
• The continents continue to
drift today.
B. Scientists
2. Jean-Baptiste Lamarck (mid-1800s)
a. Proposed that life evolves/changes
b. Proposed that by using or not using a
body part, an organism develops certain
acquired characteristics- **thought these
could be passed on to offspring**
c. “Inheritance of Acquired Characteristics”
Lamarck’s Giraffe
C. Charles Darwin
1. Mission:
to study the geology, plants, animals he encountered
on his voyage for 5 years
2. Ship was the H.M.S. Beagle
3. Focused on the Galapagos
Islands
4. Observations:
a. too many organisms are
produced
b. organisms vary
c. organisms struggle to
survive (fight for food,
mate, habitat, etc.)
d. the fittest for the environment survive
e. the fittest get to reproduce and pass on their
genetic traits
C. Charles Darwin
3. Main Points:
A. Descent with modificationorganisms over long amount of time
will accumulate different
modifications to survive in
environment
B. Theory of Natural Selection
individuals with inherited characteristics
well-suited for their environment survive to leave
more offspring on average than other individuals;
“Survival of the fittest”
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?
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
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
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
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: organisms that very
similar evolve to become very different
B. Convergent evolution:
when unrelated organisms evolve similar
adaptations because of similar environment
Ex: sharks and dolphins share analogous body
plans, yet have different ancestral backgrounds
(fish versus mammal)