Evolution
Chapter 15 + 14.2
Do Now

1. What about the skeleton in the
photo reminds you of a living thing?

2. What about the skeleton reminds
you of a nonliving thing?

3. What might studying this skeleton
help you to learn about living things?

4. What might be some benefits of
studying living things?
Answers




1/2. The skeleton is made of organic materials
and was once
part of a living thing, but the skeleton cannot
move on its own, reproduce, or grow.
3. Studying the skeleton could reveal how the
internal structure of a living thing is
supported, how bones are formed, or how
living things grow.
4. The study of living things can help people to
understand themselves and might lead to
practical benefits such as cures for disease,
improvements to the environment, and more
efficient use of Earth’s resources.
What is evolution?

Change in living organisms over
time
Brainstorm- How was the Earth
formed?

How do scientists know this?
14.2 Origins: Early Ideas

Spontaneous Generation


is the idea that life arises from non-life.
Francesco Redi:


an Italian scientist
tested the idea of spontaneous
generation.
If you leave meat out for a week,
what happens?

Where do maggots come from?
Debating Spontaneous Generation

The Experiment:

Place meat in open container and one in a
closed container
1668 Francisco Redi


Hypothesized that maggots came from
flies, not meat
Therefore, maggots did not
spontaneously generate
1864 Louis Pasteur

Theory of biogenesis

Only living organisms can produce
other living organisms
1864 Louis Pasteur




Devised an experiment to test
spontaneous generation
Nutrient rich broth was exposed to air
but not dust and spores
Living organisms must be able to enter
the broth in order to grow
Living things do NOT spontaneously
generate
What was the atmosphere of early
earth like?

What was it made of?
How did the gases get in the
atmosphere?
Gases were expelled from
volcanoes









Water Vapor (H2O)
Carbon Dioxide (CO2)
Sulfur Dioxide (SO2)
Carbon Monoxide (CO)
Hydrogen Sulfide (H2S)
Hydrogen Cyanide (HCN)
Nitrogen (N2)
Hydrogen (H2)
NO OXYGEN!!!!!!!
Do Now

What were the conditions of early
earth?
How do we know that was what the
atmosphere was made of?


Miller and Urey created
an experiment
Showed how first
organic molecules could
be formed
Miller and Urey Experiment

Primordial soup hypothesis:



Primary Energy Sources:



early hypothesis about the origin of life
simple organic molecules could be made from
inorganic compounds.
UV light from the Sun
Electric discharge in lightning
Scientists found that hydrogen cyanide
could be formed from even simpler
molecules in simulated early Earth
environments.
Conclusion Activity-Do Now Period 6






State the scientist who came up with
different theories:
1. Discovered part of cell theory.
2. Created early earth environment to test
hypothesis.
3. First to discover that spontaneous
generation was false.
4. Worked with maggots and meat
5. Discovered primordial soup hypothesis.
Cellular Evolution




Scientists hypothesize that the first cells
were prokaryotes
Modern prokaryotes called archaea are
the closest relatives of Earth’s first cells.
Archaea are autotrophic
They do not obtain their energy from the
Sun.
Photosynthesizing Prokaryotes


Photosynthesizing prokaryotes
evolved not long after the archaea.
Prokaryotes, called cyanobacteria,
have been found in rocks as old as
3.5 billion years.
Do Now



1. ______ is thought to be an
ancestor of the first cells on Earth.
2. What gas was missing from the
atmosphere of early Earth?
3. How old is the Earth?
Do Now

List the three scientists we
discussed last class and a sentence
about each experiment.
The Endosymbiont Theory



Eukaryotic cells lived in association with
prokaryotic cells.
Relationship between the cells became
mutually beneficial, and the prokaryotic
symbionts became organelles in
eukaryotic cells.
This theory explains the origin of
chloroplasts and mitochondria.
Endosymbiont Theory
Evidence for Endosymbiont Theory

http://www.sumanasinc.com/w
ebcontent/animations/content/
organelles.html
Evidence for Endosymbiont Theory
Supporting Evidence for
Endosymbiotic Theory





Mitochondria have circular DNA like
bacteria
Replicates like bacteria separate
from the host cell
DNA codes for proteins that are
similar to bacterial proteins
Mitochondria make their own
proteins
Mitochondria have two membranes
(one from the host cell and one
from their own cell membrane)
Do Now

Label the following diagram
Endosymbiotic Theory
Who is Charles Darwin?
15.1 Darwin on the HMS Beagle


Darwin was a Naturalist
He collect biological and geological
specimens during the ship’s travel.
The Galápagos Islands



Darwin collected mockingbirds, finches, and
other animals on the four islands.
Darwin discovered that each island had their
own, slightly different varieties of animals.
Almost all species collected were unknown
to European scientists
Frigate bird
The Galápagos Islands (Cont.)


Populations from the mainland changed
after reaching the Galápagos.
Darwin hypothesized that new species
could appear gradually through small
changes
Do Now

Label the following diagram
Darwin’s Conclusion


Humans could change species by
artificial selection, then the same
process could work in nature.
Ex) Corn Selection
Artificial Selection
Brassica oleracea
Endosymbiotic Theory
What is natural selection?
Natural Selection

1. Individuals in a population show
variations.
Natural Selection (Cont.)

2. Variations can be inherited.
Natural Selection (Cont.)

3. Organisms have more offspring
than can survive on available
resources.
Natural Selection (Cont.)

4. Variations that increase
reproductive success will have a
greater chance of being passed on.
Do Now

Explain using Darwin’s Theory of
Natural Selection (all 4 parts!) why
tall trees evolved.
Do Now- Multiple Choice
1. What did
Darwin infer from
his observations
of artificial
selection?
A. Animal breeders could create new species.
B. A similar process could work in nature.
C. Reproductive success could be increased.
D. Variation in a species could be produced.
2. What is the
A. They mean the same thing.
B. Evolution works against natural selection.
C. Evolution explains how natural selection
works.
D. Natural selection explains how evolution
works.
relationship
between natural
selection and
evolution?
3. Which explains
A. The different tortoises were different
why the tortoises on species.
the different islands B. The environment on each island was
different.
of the Galápagos
C. Each type of tortoise could survive only on
had slightly
its own island.
different variations
D. They arrived on the islands from different
in their shells?
continents.
Use the following example and
explain the four parts of natural
selection.

A male peacock has bright colored
feathers to attract a mate

1. Variation

2. Inherited


3. More offspring are produced than can
survive
4.Varations with Reproductive Success
Sample Example

Using the following example,
explain how natural selection
created the evolution of this
butterfly.
Explain how natural selection can lead
to evolution of this moth.
Quiz on 14.2 and 15.1






Darwin
Natural Selection
Artificial Selection
3 Scientists (Miller/Urey, Redi, Pastuer)
Endosymbiont Theory
Early prokaryotes/early Earth conditions
Types of Natural Selection




1.
2.
3.
4.
Stabilizing Selection
Directional Selection
Disruptive Selection
Sexual Selection
1. Stabilizing Selection

Eliminates extreme
expressions of a trait
because the average
expression increases
survival

Ex: most human
babies are born with
average weights
2. Directional Selection

This happens when an extreme version
of a trait makes an organism more fit.

Ex. Speed; faster is always better so a
population will tend to get faster over time.
3. Disruptive Selection

A process that splits a population into two
groups because the organisms that express
either extreme trait survive and the average
trait does not.

Ex: Snake coloration
4. Sexual Selection


Frequency of a trait is based on the
ability to attract a mate.
Males evolve with threatening
characteristics or bright colors to
attract females.
Worksheet**

Video – Planet Earth (Jungles)
Do Now




In a population of mice, the colors
range from light to dark grey. The
mice live among dark colored rocks.
1. What mice to you think would
survive natural selection?
2. What would happen over time to
the entire mice population?
3. What is the name of this type of
natural selection?
Think – Pair - Share


Brainstorm- How do scientist know
that evolution occurred?
What are some evidence for
evolution?
15.2 Evidence for Evolution




1.
2.
3.
4.



Fossil Evidence
Evidence from Anatomy
Embryology
Biochemistry
Genetic Evidence
5. Geographic Distribution
6. Direct Observation
1. Fossil Evidence


Fossils provide a record of species
that lived long ago.
Fossils show that ancient species
share similarities with species that
now live on Earth.
2. Evidence from Anatomy

A. Homologous Parts

Anatomically similar structures
inherited from a common ancestor are
called homologous structures.
2. Evidence from Anatomy

B. Vestigial Structures

Structures that are the reduced forms
of functional structures in other
organisms.
2. Evidence from Anatomy

C. Evolutionary Theory

.
Predicts that features of ancestors that no
longer have a function for that species will
become smaller over time until they are lost.
Do Now – Period 1

Use Darwin’s idea about natural
selection to explain how green
beetles became the predominant
color over time.
2. Evidence from Anatomy

D. Analogous Structures:


Can be used for the same purpose
(look similar), but not inherited from a
recent common ancestor
Ex. Wings of an eagle and beetle
Think-pair-share


Compare and contrast analogous
and homologous structures.
List 3 examples of each not
mentioned in class.
3. Embryology


Vertebrate embryos exhibit
homologous structures during
certain phases of development
Become totally different structures
in the adult forms.
4. Biochemistry

Common ancestry can be seen in
the complex metabolic molecules
that many different organisms
share.

Ex. Hemoglobin, amino acids
4. Biochemistry – Genetic Evidence


Mutations are the
raw material for
evolutionary
change
Genetics can tell
us how different
groups of
organisms are
related back
through time.
5. Geographic Distribution


The distribution of plants and animals
that Darwin saw first suggested
evolution to Darwin.
Ex. Animals on S. America mainland
were more similar to other S. American
animals than to animals living in
comparable environments in Europe
6. Direct Observations


Some evolution takes place more
rapidly than others
Ex. evolution of drug resistant
bacteria. This type of evolution can
be directly observed by scientists.
Conclusion Activity
Match the following with the type of evidence
1. The HIV virus is constantly A. Fossil Evidence
changing and evolving.
2. All living things share the
same amino acids
B. Biochemical Evidence
3. Evidence that Dinosaurs
were once on earth
C. Embryology
4. Humans and Chimps have D. Direct Observation
similar bone structures
5. The fetus of a pig and dog E. Evidence from
go through similar
Anatomy
developments
Do Now

What is a species?

Can two different species mate?

If so, what happens?
15.3 Speciation (pgs. 438-441)



A species -group of organisms that can
interbreed and produce fertile offspring
in nature.
Interspecies breeding can sometimes
produce offspring that are infertile
EX. horses and donkeys producing mules
Adaptation


A trait shaped by natural selection that increases an
organism’s reproductive success
Fitness:
 How well an organism is suited for an environment
 How well an organism can pass it’s traits to the next
generation
Types of Adaptation

1. Camouflage:

Allows an organism to become almost
invisible to predators
Types of Adaptation (Cont.)
 2. Mimicry:
 One species evolves to resemble
another species.
Western coral snake (poisonous)
California kingsnake (harmless)
Do Now

List 3 evidences for evolution and
provide an explanation of each.
Types of Evolution

A. Divergent Evolution



Adaptive Radiation
B. Convergent Evolution
C. Coevolution
A. Divergent Evolution

Divergent Evolution


When one species evolves into two or
more species with different characteristics
One type of Divergent evolution is called
adaptive radiation.
A. Divergent Evolution (cont.)


Adaptive Radiation: One species gives
rise to many different species in response
to the creation of new habitat or some
other ecological opportunity
Can occur in a relatively short time
A. Divergent Evolution (cont.)



Divergent evolution can sometimes lead
to reproductive isolation.
Prevents two species from mating.
It can be caused by:


1. geographic isolation (allopatric speciation)
2. genetic mutations (sympatric speciation)

Polyploidy:
B. Convergent Evolution


Unrelated species evolve similar traits
even though they are not closely related.
These traits are often structurally very
different.
Examples

Bird Wing
Bat Wing
Analogous Structures

Result from Convergent Evolution
Squid Eye
Human Eye
C. Coevolution



Relationship between two species in which
the evolution of one species affects the
evolution of the other species.
Mutualism
Coevolutionary arms race
Orchid Fly
Garter snake consumes a poisonous newt
http://www.pbs.org/wgbh/evolution/library/01/3/l_013_07.htm
Label the following:
Do Now

Explain the difference between
divergent and convergent evolution
Explain the differences between:


Homologous and analogous structures
Convergent and divergent evolution
Tempo of Speciation

Gradualism:


Evolution proceeds in small, gradual
steps according to a theory called
gradualism.
Punctuated Equilibrium:

Punctuated equilibrium explains
rapid spurts of genetic change causing
species to diverge quickly.
Chapter 15 Evolution
Do Now

Explain this picture. Use as many
vocab words as possible…
Do Now

How did humans evolve?
Human Evolution Ch. 16.2

Primate adaptations




high level of problem solving ability
large brain size when compared to
body weight
flexible shoulders
flexible hand with an opposable thumb
Primate Evolution
16.2 Hominoids to Hominins
Hominins
 The lineage that most likely led to humans
split off from the other African apes
sometime between 8 and 5 mya.
 Hominins have bigger brains.
 Thinner and flatter face
 Smaller teeth
 High manual dexterity
 Bipedal
African Origins
Human Evolution
Conclusion Activity

Compare and Contrast Apes and
Humans
Notebook File
Do Now


Homologous and analogous structures
Convergent and divergent evolution
Do Now

Explain how simple mutations can
cause the evolution of a new
species. Use the following words:





Adaptation
Natural Selection
Divergent Evolution
Reproductive Isolation
Sympatric or Allopatric Speciation