Transcript Evolution - Biology CP

Evolution Unit
Evolution in 1 minute
Examples of Evolution
Write down 5 animals.
Next to the animal, explain the environment
that they live in.
Explain how each of these animals may be
adapted to the environment that they live in.
We will study…
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History of Earth
Darwin’s theory of evolution
How scientific thought changed during his era
Evidence of evolution
Constructing a timeline of Earth’s History
See TIMELINE OF EARTH ACTIVITY
Movement of Earth’s Crust
Sea
level
Sea
level
Sedimentary
rocks form in
horizontal layers.
When part of Earth’s
crust is compressed,
a bend in a rock
forms, tilting the rock
layers.
As the surface
erodes due to water,
wind, waves, or
glaciers, the older
rock surface is
exposed.
New sediment is
then deposited
above the exposed
older rock surface.
Evolution
How did Homer Simpson evolve?
http://www.youtube.com/watch?v=faRlFsYmkeY
Guiness’ version of evolution
http://www.youtube.com/watch?v=1t4sdgvy-pk
Cartoon Evolution of Man
http://daily.swarthmore.edu/static/uploads/by_date/2009/02/19/evolution.jpg
Monkey’s View of Evolution
http://www.googlyfoogly.com/pictures/Monkey-Evolution.html
Interest Grabber
When Is a Flipper a Wing?
All living things are related. Some relationships are easy to
see—your pet cat may not roar like a lion, but it clearly
resembles one.Other relationships are less obvious.
Interest Grabber continued
1. On a sheet of paper, construct a table that has five
columns and six rows. In the columns, write the following
heads: Animal Group, Example, Legs, Fins, and Tail. Then,
place the following animal groups in their own row:
Mammal, Bird, Fish, Amphibian, Reptile, and Insect.
2. Give one example for each group, and then fill in the
information for that example. For Legs, write in the
number of legs that each animal has. Do animals with fins
have legs? Do animals with wings have legs? If so, how
many?
3. Can you tell from your table if a fish is more closely related
to a bird or to an amphibian? Explain your answer.
What is evolution?
Evolution is the process by which modern organisms
have descended from ancient organisms
How did the idea of evolution develop?
Many scientists had their own ideas on how life on
Earth developed. These scientists include, but are
not limited to:
CHARLES DARWIN, JEAN-BAPTISTE LAMARCK, AND
LYELL, THOMAS MALTHUS
Lyell - 1833
Lyell stressed that
scientists must explain
past events in terms of
processes that they can
actually observe
Lyell’s work:
- explained how
geological features are
built up/torn down over
long periods of time
Lyell’s influence on Darwin
Lyell’s understanding of Darwin
influence Darwin to think:
1. If the Earth can change over
time, life might change also
2. It would take many years for
life to change in the way Lyell
suggested
Lamarck’s Ideas of Change
Lamarck proposed the idea of USE and DISUSE of
organs. By USING or NOT USING organs, an
organism would acquire or lose them in their
lifetime. These traits would then be passed on to
their offspring. Over time, this led to change in a
species.
Lamarck’s Theory of Evolution
Lamarck’s theory centered around:
1. Tendency toward perfection
- all organisms have an innate tendency toward
complexity /perfection organisms change and
acquire features to help them survive
2. Use and disuse
- organisms can alter the size/shape of an organ
by their bodies use of it
Lamarck’s Theory of Evolution
3. Inheritance of acquired traits
- acquired characteristics can be inherited and
passed along
How would Lamarck the evolution of
the crabs?
Lamarck’s Theory with Giraffe’s
Looking at the picture to the
right, explain in your own
words, Lamarck’s theory on
giraffe’s and the length of their
necks.
Evaluating Lamarck’s Hypothesis
Lamarck’s hypothesis is incorrect because:
1. He did not know how traits were inherited
2. He did not know that an animals behavior has no
effect on inherited characteristics
He did, however, help pave the way for other
biologists…
Thomas Malthus’ Idea of Population
Change
Malthus believed that is a population continually
grows and is not “checked”, eventually there
would not be enough resources for that species
to survive
Forces that work against growth are war, famine
and disease
Charles Darwin’s Idea on Change
In 1831, Darwin traveled on the H.M.S. Beagle for a
voyage around the world
On his travels he made many observations and
with the help of others, collected evidence to
help propose a hypothesis on how species
evolve.
This hypothesis led to the theory of evolution, also
known as natural selection.
Darwin’s Travels
Darwin’s Observations
• He observed plants and animals and the
environments they lived in.
• He looked at the offspring that came from
reproduction from species
• He looked at and wondered why certain species
survived and others did not
Darwin’s Collections
He collected fossils - preserved remains of ancient
organisms
He noticed some fossils resembled organisms that
were living
other fossils did not recognize anything ever seen
The Galapagos Islands
Darwin traveled to a group of islands off the coast
of South America
These islands had very different climates
He noticed that characteristics of plants and
animals on each island differed, although they
looked similar
He wondered if at one time, all these species were
related and evolved from species from the
mainland of South America
What did Darwin Observe?
Pinta
Pinta Island
Tower
Marchena
Intermediate shell
Fernandina
James
Santa Cruz
Isabela
Santa Fe
Hood Island
Floreana
Isabela Island
Dome-shaped shell
Hood
Saddle-backed shell
Tortoises
Why do these tortoises look different?
Write down your reasoning and explanations.
What else did Darwin study?
In your notes, write down your observations of
each bird. In addition, next to each trait, explain
why each bird may have that characteristic.
On the Origin of Species
After all his observations Darwin wrote a book to
summarize his data and his hypothesis (1859)
Darwin’s hypothesis
In his book, Darwin:
1. Proposed the idea of Natural selection – a
mechanism for evolution of species
2. Gave evidence to support his hypothesis
Natural Variation and Artificial Selection
Natural variation - members in a species vary from
one another
Darwin noted that breeders of plants and animals
pick specific traits of an organism.
for example: the largest pigs, the fastest horses,
and cows that produce the most milk
Darwin called this artificial selection
Artificial selection
Selection by humans for breeding of useful traits
from the natural variation among different
organisms
Evolution by natural selection
Darwin believed evolution occurred by natural
selection because:
1. animals struggle for existence
2. fit animals survive
3. organisms descend with modifications
1. Struggle for existence
Darwin concluded that high birth rate and shortage
of life’s basic needs causes organisms to struggle
to exist. This causes organisms to compete for
resources
2. Survival of the fittest
Fitness – the ability of an organism to survive and
reproduce in its environment
result of adaptations – an inherited characteristic
that increases an organism’s chance of survival
survival of the fittest = natural selection
traits being selected contribute to an organism’s
overall fitness in their environment
Adaptations
Over time…
Natural selection results in changes in inherited
characteristics of a population. These changes
increase a species’ fitness in their
environment.
3. Descent with modification
Natural selections causes organisms to have
different structures, establish different niches
and occupy different habitats
Each living species has descended over time,
with changes, from other species
Called descent with modification
Peppered Moths
Before Industrial
Revolution
During Industrial
Revolution
Evidence of
Evolution
includes
The fossil record
Geographic
distribution of
living species
Homologous
body structures
Similarities
in early
development
which is composed of
which indicates
which implies
which implies
Physical
remains of
organisms
Common
ancestral
species
Similar genes
Similar genes
Evidence of evolution
Evidence is included:
- In the fossil record
- In geographical distribution
- Homologous structures
- Similarities in embryology, early development
The Fossil Record
By comparing fossils from older rock layers with
younger rock layers you can see the change of
Earth over time.
Human Evolution Pedigree
Human Evolution Timeline
Geographical distribution
Similar, but unrelated species in different parts of
the world
Beaver
Beaver
NORTH
AMERICA
Muskrat
Muskrat
Beaver and
Muskrat
Coypu
Capybara
Capybara
SOUTH
AMERICA
Coypu
Coypu and
Capybara
Homologous structures
Homologous structures - Structures that have
different mature forms but develop from the
same embryonic tissues
NOTE: not all homologous structure serve important
functions even though they resemble important
structures in other organisms vestigial organs
Homologous Structures
Turtle
Alligator
Typical primitive fish
Bird
Mammals
Similarities in embryology
The early stage of many animals is very similar
The same embryonic cells develop in the same
order and in similar patterns to produce tissues
and organs of all vertebrates
Summary of Darwin’s Theory
1. Individual organisms in nature differ from one
another. Some of this variation is inherited.
2. Organisms in nature produce more offspring
than can survive, and many of those that survive
do not reproduce.
3. Because more organisms are produced than can
survive, members of each species must compete
for limited resources.
4. Because each organism is unique, each has
different advantages and disadvantages in the
struggle for existence.
5. Individuals best suited to their environment
survive and reproduce most successfully. The
characteristics that make them best suited to
their environment are passed on to offspring.
Individuals whose characteristics are not as well
suited to their environment die or leave fewer
offspring.
6. Species change over time. Over long periods,
natural selection causes changes in the
characteristics of a species, such as in size and
form. New species arise, and other species
disappear.
7. Species alive today have descended with
modifications from species that lived in the past.
8. All organisms of earth are united into a single tree
of life by common descent.
Example of Evolution - Camouflage
http://www.youtube.com/watch?v=EJGtNigCu8&safe=active
1. What do you think is the purpose of the diagram
above?
2. How do you think it is organized? Why is it
organized in the way it is? Be as specific as you
can
Lamarck vs. Darwin
1. How would Lamarck explain the evolution of the
characteristic described? You must list all the steps
of his theory and use the correct terminology.
2. How would Darwin explain the same
characteristics? You must include all the steps of
Darwin’s theory and use the correct terminology.
Other examples of evolution
Vultures are bald
Opossums
Chickens roosting
Sea Turtles
Killdeer