Transcript what happens how it leads to change

Ideas About
Evolution
Describe Lamarck’s hypothesis of acquired
characteristics and Darwin’s theory of natural
selection.
Identify why variations in organisms are important.
Compare and contrast gradualism and punctuated
equilibrium
Early Models of
Evolution
SPECIES
group of organisms that share similar characteristics
and can reproduce among themselves, producing fertile
offspring
EVOLUTION
change in inherited characteristics over time
NATURAL
SELECTION
process by which organisms with traits best suited to
their environment are more likely to survive and
reproduce
VARIATION
inherited trait that makes an individual different from
other members of the species
ADAPTATION
any variation that makes an organism better suited to
its environment
Lamarckism
Characteristics developed during a parent’s lifetime
are inherited by the offspring. Evidence does not
support this.
Darwin’s Finches
Darwin’s Finches
The Galapagos finches ______________________
for food. Those that
competed
had
advantages
beak shapes
_____________________,
______________________
that allowed them
to get food
survive
reproduce
were able to _________________ longer and _____________________
species
more.
Over time, groups of finches became separate ___________________.
Darwin’s 5 Principles of Natural Selection
1. Organisms produce more offspring than can
survive
2. Differences, or variations, occur among individuals of a
species
3. Some variations are passed to offspring
4. Some variations are helpful. Those with helpful
variations
survive and reproduce better.
5. Over time, offspring of individuals with helpful variations
make
up more of a population and may become a new species.
Variation vs.
Adaptation
Variation vs.
Adaptation
DEFINITION
EXAMPLES
VARIATION
ADAPTATION
AN INHERITED TRAIT THAT MAKES AN
INDIVIDUAL DIFFERENT FROM OTHER
MEMBERS OF ITS SPECIES
ANY VARIATION THAT MAKES AN
ORGANISM BETTER SUITED TO ITS
ENVIRONMENT
Polar Bear
Two layers of fur
Small ears
Black
skin
Long claws
Sensitive
nose
Webbed feet
Cuttlefish camouflage
http://www.youtube.com/watch?v=pgDE2DOICuc
Variation vs.
Adaptation
CHANGES IN
GENE SOURCES
GEOGRAPHIC
ISOLATION
WHAT HAPPENS
HOW IT LEADS TO CHANGE
OVER TIME, GENETIC MAKEUP OF A
SPECIES
MAY CHANGE
WHEN NEW INDIVIDUALS ENTER AN
AREA
THEY CAN BRING IN DIFFERENT
GENES AND VARIATIONS
MOUNTAINS AND LAKES CAN ISOLATE
INDIVIDUALS FROM THE POPULATION
OVER SEVERAL GENERATIONS,
VARIATIONS
NOT COMMON IN LARGE POPULATION
MAY BECOME COMMON IN ISOLATED
POPULATION
http://www.youtube.com/watch?v=MAZfEdthTlo
Gradualism vs Punctuated
Equilibrium
Rapid change with
few mutations
Slow, ongoing
process
Continuous
series
of mutations
Intermediary forms
- gradual change
Both show
evolution
Bacteria can
change
in just a few
generations
Clues About
Evolution
Identify the importance of fossils as evidence of
evolution
Explain how relative and radiometric dating are
used to estimate the age of fossils
List examples of five types of evidence for
evolution
Clues About Evolution
SEDIMENTARY
ROCK
a type of rock made from pieces of other rocks,
minerals deposited from a solution, or plant and animal
matter
RADIOACTIVE
ELEMENT
element that gives off a steady amount of radiation as it
slowly changes to a nonradioactive element
EMBRYOLOGY
study of embryos and their development
HOMOLOGOUS similar in structure, origin or function
VESTIGIAL
structure that does not seem to have a function and that
may have functioned in the body of an ancestor
Green River Formation
Green River Formation
Clues About
Evolution
Relative
age of the
rocks
Habits and
behaviors
of ancient
life
Show what
organisms
looked like
Information
obtained
from
fossils
Show that
evolution
has
happened
Relative Dating
Youngest
Oldest
Relative Dating
Clues About
Evolution
Homologo
us
Structures
Embryolog
y
Other
clues
about
evolution
Vestigial
Structures
DNA
Embryology
Homologous
Structures
Convergent Evolution
Vestigial Structures