Transcript unit 7 theory of evolution

The Theory of Evolution &
Natural Selection
UNIT 7: Chapter 14-18
What is evolution?
A change in species overtime.
The Horse
Over 60 million years, the
horse evolved from a
dog-sized creature that
lived in rainforests into an
animal adapted to living on
the plains and standing up
to 2m high.
In the process, its multitoed feet, adapted for
walking across the forest
floor, evolved into singletoed hooves more suited
for running over open
country.
Charles Darwin
Darwin was born in
1809.
He sailed around
the world (it took 5
years)
He searched for
scientific
explanations for
the diversity of life.
Sailed on the HMS
Beagle.
He was a
naturalist.
Charles Darwin’s Voyage
Charles Darwin
Wrote a book on the Origin of Species
Sailed with the HMS Beagle
Observations made in the Galapagos
Islands
These observations helped him form
the theory of how species change
over time called natural selection
What did Darwin study?
Finches
Tortoises
On the Galopagoes Island
What is Natural Selection?
Natural selection is governed by the
principles of genetics.
Also known as “Survival of the Fittest”
Did the Biosphere adapt or
evolve over time?
Giant Tortoises of the Galápagos
Islands
Section 15-1
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
Evidence for Evolution
1. Fossil record
2. Anatomy
Homologous structures
Analagous structures
3. Vestigial structures
4. Embryology
5. Molecular biology (DNA differences)
Mechanism for change in a
population of organisms:
Animals who have greater fitness
survive in environment and live to
reproduce.
Random changes in DNA (called
mutation) can lead to greater or less
fitness.
Adaptations allow an organism to
survive better in their environment.
Who’s More Fit…..
Bear without claws
Bear with claws
Adaptations
large, flat feet, to spread their weight on the
sand of their desert habitat
thick fur on the top of the body for shade,
and thin fur elsewhere to allow easy heat
loss
a large surface area to volume ratio, to
maximise heat loss
the ability to go for a long time without
water (they don't store water in their humps,
but they lose very little through urination and
sweating)
the ability to tolerate body temperatures up
to 42°C
slit-like nostrils, and two rows of
eyelashes, to help prevent irritation from
sand.
a white appearance, as camouflage
from prey on the snow and ice
thick layers of fat and fur, for
insulation against the cold
a small surface area to volume ratio,
to minimise heat loss
a greasy coat, which sheds water after
swimming
Japanese Spider Crab
Types of Adaptations
Protective Coloring
Camouflage
Mimicry
Physiological Adaptations
Reproductive Changes
Other changes
Behavioral Adaptations
Peppered Moth Lab
DO NOW--What are some similarities amongst
these birds?
Prehistoric Bird
Turkey
Lamarck’s Theory of Evolution
Section 15-2
LAMARCK PROPOSED THAT IF AN ORGANISM USED OR DIDN’T
USE ORGANS (OR BODY PARTS) WOULD CAUSE IT TO CHANGE
OVERTIME. His hypothesis was incorrect!!!
Jean-Baptist Lamarck
French naturalist
Born before Darwin
First to form a
hypothesis of
evolution.
He finally realized
organisms adapt to
their environment—
don’t loss or gain traits
from lack of using
organs.
Adaptations
Can arise in response to
environmental pressures
Temperature
Antibiotic resistance in bacteria
Pesticide resistance
Morphological changes in peppered
moths
Yellowstone Park Environment
America’s first national park
Variety of wildlife (grizzly bears, wolves,
bison, elk)
Preserved national park
Located in Wyoming, Montana and Idaho
Bacteria can survive in 400 degrees F. This
is an example of adaptation.
http://www.yellowstoneparknet.com/geoth
ermal_features/hot_springs.php
What is a Population?
Populations are groups of
interbreeding individuals that live in
the same place at the same time.
Populations evolve over many
generations, individuals don’t!
Individuals in a population compete
for resources with each other.
How Does Evolution Work?
Populations produce more offspring
than the environment can support.
The unequal ability of individuals
to survive and reproduce leads to
the gradual change in a population
over many generations.
How are new species created?
Geographic isolation
Reproductive barriers
Change in chromosome numbers
Adaptive radiation
What is Extinction?
The Dodo Bird
Review Evolution:
1.
2.
3.
4.
What is evolution?
What is natural selection?
Who was Charles Darwin?
What are 5 evidences that support
evolution?
5. Describe a younger and older fossil
and ground layers they would be
fossilized in.
Answers
1.
2.
3.
4.
5.
A change in species overtime.
Favorable variations that enables an organism
to adapt successfully to a change in the
environment.
He formed theory of evolution—species change
overtime.
Fossil record, Anatomy, Vestigial structures,
Embryology, Molecular biology
Younger layer would be in top ground sediment.
Older layer would be below younger layer of
fossil remains.