The document discusses key concepts in evolution including: 1) Natural selection and artificial selection lead to gradual changes in species over time as organisms adapt to their environments. 2) Charles Darwin's observations on his voyage on the Beagle led him to propose the theory of evolution by natural selection to explain changes in species over time. 3) Evidence for evolution includes comparative anatomy, fossils, and DNA similarities that demonstrate common ancestry between species.

1. Changes Over Time

2. Warm-up: For the first five minutes of class quick-write about the following
question in your notebook. Your answers do not need to be correct, just write
what you know or think you know.
Explain in your own words you understanding so far of the following terms:
Artifical Selection
Natural Selection
Evolution

3. Pre-Darwin
Before Darwin, many scientists had dedicated their lives to
categorizing the species of the world.
A scientist named Carl Linneaus made numerous travels
throughout the globe and noticed that everywhere he went,
similar species existed with slighty different changes in each
location.
This led him to believe that some form of adaptation existed
among organisms, and helped him classify many of the species
in existence into different categories.

4. Darwin
In 1831 Charles Darwin embarked on a 5 year voyage on the SS
Beagle around the globe.
After studying thousands of species of organisms on each of the
continents he hypothesized that every similar species had a
common ancestor.
While studying species on the isolated Galapagos Islands the
differences between mainland and island species made him
reason that plants and animals may have changed gradually
over time due to differences in their environments.
This gradual change over time is called evolution.
Upon returning from his trip, Darwin spent the next decades of his
life testing his hypothesis to form a scientific theory.
A Scientific Theory is a well tested concept which explains a wide
range of observations.

5. Evolution
For many thousands of years humans had used artificial selection
to breed plants and animals.
Aritificial Selection is when humans use the natural processes of
evolution by choosing which species with which specific traits
will pass on their genes.
Natural Selection is this process as it occurs in nature. Organisms
adapt to their surroundings and change over time to better
survive and create more offspring.
By creating more offspring, the genes which helped one
organisms survive will pass on to the children, allowing them to
also better survive.
All of this is possible because of genetic variation among each
individual organism.

6. Evidence for Evolution
Comparative Anatomy shows us the similarities in characteristics
of modern and ancient species.
Homologous Structures are body characteristics which are similar
between two species.
This can tell us which species are likely to have a common
ancestor.

7. Also:

8. Evidence for Evolution
Other clues to show the relation between two species are
similarities in DNA and in early development.

9. Fossils
Fossils tell us a great deal about how life has developed over
time.
Finding well preserved fossils is very difficult because so many
perfect factors are required to preserve remains.
Trace fossils are incomplete fossils which show evidence of life in
the past.
Because life decomposes fully, there are many gaps in the fossil
record, but new discoveries are found every year and the gaps
fill in quickly, giving us a clearer picture of how life has changed
over time.

10. New Species
Evolution is the change in characteristics of an organismover
time. But when can we determine that a new species is born?
A new species forms when a group of individuals remains isolated
from the rest of it's species long enough to evolve different traits.
We know something is a new species when it is unable to breed
with the species it originally came from.

11. Common Ancestor
A Common Ancestor is the distant relative of any two species.
If you go back far enough, every single organism on earth has a
distant relative, some are more closely related than others.