Fossils: Traces of Life Gone By
o Continental Drift: Pangea, land has broken apart and reformed into the
current arrangement of continents.
o Plate tectonics: current theory of continental drift, closely tied to changes in
the earth’s biological makeup.
o Extinction: complete disappearance of a specie.
1. Fossils are not easily formed and are used as a major piece of bio-evolutionary form
of evidence.
2. Fossils can provide evidence of how an organism lived and how Earth has changed
over time.
3. Earth experiences gradual changes that can shift the way species evolve and where
fossils are found.
4. Different types of species have changed over time, new species emerge or branch off
of old species.
5. Of all the species that existed on Earth 99% are extinct and there are many new
species emerging.
Technologies That Strengthen Fossil Evidence
o Stratigraphy: determining the relative age of fossils by looking at the strata
or rock layers.
o Radioactive isotopes: elements that undergo decay, a more direct method
than stratigraphy.
1. There are 2 ways to date fossils to further our understanding of evolution: direct
and indirect methods.
2. Indirect is stratigraphy which only dates a fossil base don the rock layer it is found
in. (modern versus ancient)
3. Radioactive isotopes or carbon dating is more precise because it pinpoints a date in
time based on the decay of elements.
4. Scientists will sometimes combine radioactive isotopes with other methods of fossil
dating such as measuring magnetic properties.
5. Dating fossils have also helped scientists determine the geological record.
Modern Life: Evidence for Evolutionary Change
No vocab words
1. Change occurs in a specie over long periods of time (finches)
2. Homology is a characteristic that is similar among different organisms because they
evolved from a common ancestor.
3. Vestigial structures are useless structures that may have served a purpose in a
common ancestor.
4. DNA is found in simple structures such as bacteria and more complex structures
such as fungus, plants, and animals.
5. The similarity in genetic code across living organisms strongly suggests a common
origin for all modern life.
Primates Show Change Across Time

Hominid: walked upright, brain cases similar to apes, brains were larger for
their body size.
1. The ability to use our hands the way we do is a process that has evolved over time.
2. The primate group consists of lemurs, chimpanzees, gorillas, orangutans, and
humans.
3. Lucy is a hominid that belonged to a group known as Australopithecus. (more
human like front teeth, erect bipedal posture)
4. 1995, a new species of hominid was discovered, Australopithecus anamensis
(4.1myo)
5. These evidences suggest that hominids split from the common ancestor shared with
chimpanzees about 6 mya.
Darwin Proposes Descent with Modification
No vocab
1. Darwin noticed that although some organisms belonged to the same specie they
varied based on the geographical location that they were in, and some species more
closely matched than others.
2. Descent with modification: all organisms on earth are related through descent from
some unknown ancestral type that lived long ago.
3. Darwin was surprised to learn that other scientists (Wallace) were actually noticing
and studying the same ideas that he was.
4. Darwin is the author of the origin of species which did not use the term evolution.
5. Darwin is known as the father of evolution.
Evolution by Natural Selection
o Specie: a group of organisms whose members very closely resemble each
other because they share many key characteristics.
o Adaptation: beneficial traits that help an organism survive.
o Competition: acts as a selective pressure due to organisms fighting for
limited resources
o Predation: another pressure that is required in order to survive
(predator/prey relationships)
1. Individual members of a population show great variation. (Kale)
2. Some species reproduce faster than what the land or resources available can handle
(this limits populations).
3. Variations can be inherited from one organisms to the next.
4. Adaptations are directly linked to natural selection (survival of the fittest).
5. Selective breeding is artificial breeding (human do the selecting not the
environment).