Transcript 8-1.1-Evolution-and-Natural-Selection-Power-Point-2

Evolution &
Natural Selection
Vocabulary
Evolution
Natural Selection
Adaptation
Overproduction
Competition
What does it mean to evolve?
What causes evolution?
What evidence do we have for
evolution?
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
GSE’s
 Genetic variations are passed on
through reproduction. LS3–9a
 Evidence for evolution illustrates
how organisms are related. LS3-9b
 Natural selection leads to
evolution. LS3-9d
 Our understanding of evolution
has changed over time. LS3-9e
Vocabulary
Evolution
Natural Selection
Adaptation
Overproduction
Competition
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Evolution
Vocabulary
Evolution
Natural Selection
Adaptation
The theory that organisms
change (evolve) over time.
Overproduction
Competition
Variations
What is a theory?
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Why have thoughts about evolution
changed?
Vocabulary
 We used to think the earth was a few
thousand years old
 We now know it is billions of years
old from looking at rock samples.
 We used to think the planet and its
inhabitants have not changed since
the beginning of time.
 We now know the planet and its
inhabitants have changed, from
observing fossils.
Adaptation
Evolution
Natural Selection
Overproduction
Competition
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Jean Pierre Lamark
 His theory was that organisms could change their
traits during their lifetime by using them or not
using them.
 These new traits were passed on to offspring and
over time the species evolved.
 Example:
Vocabulary
Evolution
Natural Selection
Adaptation
Overproduction
Competition
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Charles Darwin
(1809-1882)
Vocabulary
Evolution
Natural Selection
Adaptation
 Proposed the theory of evolution by
natural selection
Overproduction
 Voyage of the HMS Beagle
Variations
 Five-year journey to various places
across the world
 Went to South America and the south
pacific collecting specimens and
making observations
Competition
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Charles Darwin
(1809-1882)
 Kept a journal of his findings
Vocabulary
Evolution
Natural Selection
Adaptation
Overproduction
Competition
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Observation: Galapagos Finches
 The finches on each island had different types of
beaks. Why do you think that might be?
 Beaks correspond to the food the birds eat.
Vocabulary
Evolution
Natural Selection
Adaptation
Overproduction
Competition
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Darwin’s Hypothesis
 Organisms had a common ancestor
but had adapted to their particular
environments and changed over
time.
Vocabulary
Evolution
Natural Selection
Adaptation
Overproduction
Competition
What is an ancestor?
 Evolution is due to a process called
natural selection.
 Published his theory in On the Origin
of Species in November, 1859
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Natural Selection
Vocabulary
Evolution
Natural Selection
Organisms best adapted
to their environment have
a better probability
(chance) of surviving and
reproducing.
Organisms best adapted to their
environment survive and reproduce.
This can cause evolution.
Adaptation
Overproduction
Competition
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Adaptation
Vocabulary
A trait or behavior that
helps an organism survive
in its environment.
Adaptation
What two traits do humans have that help us
adapt?
 Thumbs
 Language Skills
Common
Ancestry
Evolution
Natural Selection
Overproduction
Competition
Variations
Homologous
Structures
Vestigial Organs
Fossils
Example of Adaptation
 How are cactuses different
from most other plants?
Vocabulary
Evolution
Natural Selection
Adaptation
Overproduction
Competition
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Natural selection leads to
evolution! Here’s how...
Vocabulary
Evolution
Natural Selection
Adaptation
Overproduction
 Overproduction
 Competition
 Variations
Competition
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
 Overproduction
 Too many offspring are produced.
 Competition
 Offspring compete for resources such
as food, water, mates, and living
space.
 Variations
 Differences in individuals of the same
species.
 They are passed on through
reproduction.
Important! Variations can make some individuals more adapted to
their environment than others. These individuals are more likely to
survive and reproduce.
Vocabulary
Evolution
Natural Selection
Adaptation
Overproduction
Competition
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
OVERPRODUCTION
COMPETITION
1.
2.
3.
4.
NATURAL
SELECTION
(best adapted are
able to survive and
reproduce)
VARIATIONS
EVOLUTION
_____________________________________________
Evidence of Evolution
Vocabulary
 Common Ancestry
 Homologous Structures
 Vestigial Organs
 Embryo Development
 Fossils
Adaptation
Evolution
Natural Selection
Overproduction
Competition
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Common Ancestry
Vocabulary
If two species evolved from a
common ancestor, then they
should share some common traits
with each other.
Adaptation
Hawaiian Honeycreeper:
Common
Ancestry
Family of birds in Hawaii. They
have similar skeletons but each
species has a different beak for
eating specific foods. Just like the
finches Darwin observed!
Homologous
Structures
Evolution
Natural Selection
Overproduction
Competition
Variations
Vestigial Organs
Fossils
Homologous Structures
Structures that are similar in two
different species.
Vocabulary
Evolution
Natural Selection
Adaptation
Overproduction
They suggest that
the organisms
evolved from
a common
ancestor.
What do you
notice about these 6
structures?
Competition
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Vestigial Organs
Vocabulary
Body organs that do not serve a
purpose.
Adaptation
Evolution
Natural Selection
Overproduction
Competition
They may have served a purpose to the
ancestors of a species.
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Examples of Vestigial
Organs
Vocabulary
 Kiwi, a flightless bird, has wings that serve
no known purpose.
Overproduction
Evolution
Natural Selection
Adaptation
Competition
Variations
Common
Ancestry
 Humans have a tailbone. Some scientists
suggest that early humans had tails like
some other mammals.
Homologous
Structures
Vestigial Organs
Fossils
Embryo Development
What do you notice about these
embryos? List two observations.
Vocabulary
Evolution
Natural Selection
Adaptation
Overproduction
Competition
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Fossils
Remains of organisms
preserved in rock.
Vocabulary
Evolution
Natural Selection
Adaptation
Overproduction
Competition
Variations
Common
Ancestry
They give us clues about
what organisms looked
like in the past, and allow
us to show how a species
may have evolved.
Homologous
Structures
Vestigial Organs
Fossils
ONE LAST THING!
Vocabulary
Darwin said that variation in organisms was a
factor of natural selection. But he could not
explain what caused variation!
Adaptation
Evolution
Natural Selection
Overproduction
Competition
What is DNA?
Variations
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
DNA is what it’s all about!
Vocabulary
We now know about DNA, the code
which determines an organism’s genes.
Natural Selection
Mutations in the code (DNA) lead to
variation.
Evolution
Adaptation
Overproduction
Competition
Variations
Mutations are changes in DNA that can
be passed on to offspring.
DNA from different species can be
analyzed to see how related they are.
Common
Ancestry
Homologous
Structures
Vestigial Organs
Fossils
Combining Evidence:
What does it mean to evolve?
What causes evolution?
What evidence do we have for evolution?