Download You DO NOT need to write this Bellwork!

You DO NOT need to write this
Bellwork!
Two species of mice live in a field in the
middle of East Texas. One mouse
species is white with black spotting.
The other is brown with white spotting.
After a year, the population of white
mice has dramatically decreased,
while the population of the brown mice
has slightly increased.
Why would this be happening?
Bellwork: January 9
Copy the questions and write your answers!
Mrs. PigglyWiggly is a carrier of the sex-linked
hemophilia allele, and Mr. PigglyWiggly is normal, as
far as blood chemistry goes. Use the letter “H” to
represent the hemophilia allele.
1. What would be Mrs. PigglyWiggly’s genotype?
2. Draw a Punnet square that shows the theoretical
genotypes among their children (cross Mr & Mrs).
3. What percent chance would their sons have hemophilia?
Science Fact of the Day:
Mosquitoes like the scent of estrogen, hence, women get
bitten by mosquitoes more often than men do.
CO: I will analyze how evolution
occurs in a population. I will
examine evidence for evolution.
LO: I will talk about evolution with
the class. I will write notes about
evolution.
Let’s chat about our potato farms!
Evolution: What is it?
Evolution: change in heritable traits of a
population across generations (over time).
Charles Darwin: contributed more to our understanding
of evolution than anyone else.
• Darwin traveled, made observations and collected evidence that
led him to propose his revolutionary process in a book called Origin of
the Species.
Population size is limited
by environmental
resources
Fitness: the ability of an organism to survive and
reproduce.
•
Fitness is the result of adaptations.
Adaptation: any inherited characteristic that
increases an organism’s chance of survival.
Successful adaptations:
- enable organisms to become better suited to
their environment
- increase an individual’s ability to survive and
reproduce.
Humans have thousands of adaptations: large brain,
opposable thumbs, excellent sensory organs, light, strong
skeleton, etc.
The Primary Mechanism of
Evolution:
Natural Selection
Natural selection: the process by which individuals with
characteristics that are not well suited to their
environment either die or leave few offspring.
1. Also referred to as survival of the fittest.
2. It is not seen directly, but only observed as changes
in a population over a long time.
Bunny Simulation
If only one species is considered the "fittest", why do we still have so many
variations among species. Why do some birds have very long pointy beaks,
while other birds have short flat beaks?
Evidence for the Theory of
Evolution
Evidence for evolution can be found in:
1. the fossil record
2. the geographical distribution of living species
3. homologous structures of living organisms
4. similarities in early development, or embryology.
5. molecular (DNA) homologies
1. Fossil record
By comparing fossils from older
rock layers to fossils from younger
layers, researchers have
discovered many hundreds of
transitional fossils that document
various intermediate stages in the
evolution of modern species from
organisms that are now extinct.
2. Biogeography: study of the
geographical distribution of plants
and animals
Darwin observed this with finches
and tortoises in the Galapagos
Islands. He noticed that there were
several different species of
birds/tortoises on the islands that
were similar to each other, but had
different adaptations. He thought
that they evolved from a common
ancestor to best fit the
environment of the island they
were on.
We can see this in other species
around the world too.
3. Homologous structures: bones and muscles that
have similar structures but perform different functions
4. Embryonic Homologies: Different organisms develop
from similar starting forms (embryos)
5. Molecular Homologies: similarities in DNA sequences among
different organisms
Because organisms evolved from a common ancestor, we find
similarities in the DNA sequence of all living organisms. The
more of a DNA match we see, the closer of a relationship the
organisms have.
Homework:
• Watch the video “Evidence of Evolution” from
Bozeman Science.
http://www.youtube.com/watch?v=cC8k2Sb1
oQ8
• Write down 5 different examples of evidence
for evolution
**There are two videos by Bozeman on this
topic. Watch the 9 minute video!