Transcript The Fossil Record

Population Change (Evolution)
Coach Devlin Marcum
Levels of Classification
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There are 8levels of classification
of living things.
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Most of classification also known
as taxonomy was done by
Swedish scientist Carolus
Linnaeus (Carl von Linnae)
He used genus and species
names to give all living things a
scientific name in a system called
binomial nomenclature.(Ex. Canis
lobo = wolf; Felis leo= lion; Homo
sapien = human
Dichotomous Keys
• 1. Sex female---2
1. Sex male---5
2. Hair color red---Susan
2. Hair color brown or
blond---3
3. Hair color blonde---Jane
3. Hair color brown---4
4. Glasses worn---Donna
4. Glasses not worn--Linda
5. Pants jeans---Caleb
5. Pants slacks---6
6. Hair color black-James
6. Hair color brown--Zach
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Sample Dichotomous Key
http://aitc.oregonstate.edu/resourc
es/pdf/activity/potato_key.pdf
A dichotomous key is a very
useful tool in helping scientists
classify organisms.
Dichotomous means “2 fork” or “2
branch”
It is a series of statements of
characteristics that help lead
you to correctly identify
organisms.
How are organisms different?
• Organisms differ in many
ways.
Where the live/environment
How they reproduce
(sexually/asexually)
What they eat
(herbivore/carnivore/omnivore/
photosynthesis/decomposer)
How they obtain food
(predator/scavenger)
How they obtain mates
How they escape predators.
• A characteristic that helps an
organism survive and
reproduce in its environment is
called an adaptation.
• Some adaptations are
physical, such as fur or scales.
• Other adaptations are
behaviors that help an
organism find food, protect
itself, or reproduce.
Do species change over time?
• Since life first appeared on
Earth, many species have died
out, and many new species
have appeared.
• Scientists observe that the
inherited characteristics in
populations change over time.
• Scientists think that as
populations change over time,
new species form.
• The Fossil Record By
studying fossils, scientists
have made a timeline of life
that is known as the fossil
record.
• The fossil record organizes
fossils by their estimated ages
and physical similarities.
• Comparing organisms in the
fossil record can reveal how
organisms have changed over
time.
Fossil Evidence
• Scientists can use two
methods to determine the
age of objects in
sedimentary rocks.
• One of those methods is
known as relative dating.
• Relative dating
examines a fossil’s
position within rock layers
to estimate its age.
• Law of Superposition- in
sedimentary rocks the
oldest layers are at the
bottom and get younger
as you go up towards the
surface.
Relative Ages/Superposition
Fossil Evidence (Whale)
Darwin’s Theory
• In the 1800s, scientists were
beginning to see evidence of
change in the fossil record, but
no one was able to explain
how change happens until
Charles Darwin.
• Darwin signed-on for a fiveyear voyage around the world
and worked as a naturalist.
• His observations helped him
form a theory about how
change happens.
Darwin’s Theory (cont.)
• Darwin’s Finches
Darwin noticed that
the finches of the
Galápagos Islands
were a lot like those
in Ecuador. And the
finches on each
island differed from
the finches on the
other islands.
Darwin’s Theory (Cont.)
• Ideas About Population
Darwin was influenced by an
essay that described the
reasons that human
populations do not grow
uncontrollably.
• Darwin knew that the
populations of all species are
limited by starvation, disease,
competition, and predation.
• Darwin reasoned that the
offspring of the survivors
inherit traits that help the
offspring survive in their
environment.
• In 1859, Darwin published a
famous book called On the
Origin of Species by Means of
Natural Selection.
• In his book, Darwin proposed
the theory that change in
populations happens through
natural selection.
• Natural selection is the
process by which organisms
that are better adapted to their
environment survive and
reproduce more successfully
than less well adapted
organisms do.
Natural Selection
Evidence of Change