2. Factoid 233
• Section 14
• Evidence for Change
• Although the fossil record is not complete,
scientists can compare modern species
with species believed to exist millions of
years ago.
3. Factoid 234
• Evolution is the process by which modern
organisms have descended from ancient
organisms.
4. Factoid 235
• Charles Darwin sailed on the H.M.S.
Beagle. During his travels, Darwin made
numerous observations and collected
evidence that led him to prose a
revolutionary hypothesis about the way life
changes.
5. Factoid 236
• James Hutton in 1785 proposed that the Earth is
shaped by geologic forces that took place over
long periods of time.
• Charles Lyell published in 1833, The Principles
of Geology that explained that the same
geologic principles occurring now are the same
as those that shaped the Earth
6. Factoid 237
• Jean-Baptiste Lamarck proposed that by
selective use or disuse of organs,
organisms acquired or lost certain traits
during their lifetime. These traits could
then be passed on to their offspring. Over
time, this process led to change in a
species.
7. Factoid 238
• Lamarck’s theory is flawed because he
had no idea how traits were passed and
the fact that behavior didn’t “change” an
organism. He is important because he
realized organisms were adapted for their
environment
8. Factoid 239
• Thomas Malthus reasoned that if the
human population continued to grow
unchecked, sooner or later there would
insufficient living space and food for
everyone.
• Darwin realized that this is even more true
for plants and animals because they
produce far more offspring than humans.
9. Factoid 240
• Darwin decided not to publish his work
until 25 years later when he received a
letter from Alfred Wallace who had
reached many of Darwin’s similar
conclusions. In 1859, Darin publish, On
the Origin of Species
10. Factoid 241
• Evidence for Change
• Scientists use DNA to compare the amino
acid and nucleotide sequences of living
species. A lot of similarities indicate that
the organisms are closely related.
11. Factoid 242
• Evidence for Change
• Embryos of many vertebrates look similar.
These physical similarities may suggest
that the organisms are closely related and
thus have a common ancestor.
12. Factoid 243
• A homologous structure is a structure that
has developed from the same tissues and
have similar internal structures, but may
look different on the outside and may have
different functions. This suggests a
common ancestor.
• Bird wings and your arms for example
13. Factoid 244
• Analogous structures do not arise from the
same tissues, but perform similar
functions. These structure are not the
result of a common ancestor, but evolved
separately.
• A bug’s wings and a chicken’s wing for
example.
14. Factoid 245
• A vestigial organ seem to have no useful
purpose now although they resemble
structures that are useful in other species.
15. Factoid 246
• Natural selection is the way in which
populations change over time as certain
organisms reproduce and pass on their
genes to future generations.
16. Factoid 247
• The success or failure of an organism
depends on its reproductive ability. To be
reproductively successful means that the
desirable traits might be passed to the
offspring.
17. Factoid 248
• A species is a group of organisms that can
interbreed and have fertile offspring.
18. Factoid 249
• A population is a group of members of the
same species living in an area.
19. Factoid 250
• A niche includes all the living (biotic) and
non-living (abiotic) factors in an organisms
environment. The niche is the organisms
role in the environment.
20. Factoid 251
• A group of populations living in an area is
called a community.
21. Factoid 252
• The process of one species becoming two
species is called speciation. This happens
when two groups become separated and
no longer can interbreed and form
offspring.
22. Factoid 253
• An adaptation can be any trait, physical or
behavioral, that helps the organism to
survive.
23. Factoid 254
• External fertilization is used by fish and
frogs. It involves them producing large
amounts of eggs just so some offspring
can be successful.
• Internal fertilization is used by higher
animals. It involves them producing fewer
eggs inside the body in which the mother
makes sure they can survive.
24. Factoid 255
• A behavior involves the way an organism
reactions to changes in its internal or
external environment.
• Hibernation, showy peacock tails, deer
fighting, etc are examples of behaviors.
