Evolution Study Guide
1. What is an adaptation?
A characteristic which helps a species to be better suited to its environment.
List some examples:
Birds for flight: Keel (flight muscle), feathers, hollow bones
Arthropods: exoskeleton
Mammals: Mammary glands, Fur
TONS OF EXAMPLES
2. Define Evolution
Populations change over time
3. What is a fossil?
Remain or imprint of once-living organism
a. How do fossils form?
-Dead organism is covered by layer of sediment
- more sediment covers
- minerals in the sediment may seep into the organism and gradually replace with
stone OR if the organism rots away completely after being covered it may leave
an imprint
4. What is a homology?
Similarity shared between two different organisms that is inherited from a common
ancestor with similar trait. Can be anatomical (tail, bones), a complex structure
(antennae), a gene sequence (gene that codes for insulin is the same in cows and
humans), or a behavior (mother taking care of young)
5. What is an analogy?
A similarity that is a result of convergent evolution (a trait that performs a similar
function as another organism but is not a result from inheritance from a common
ancestor) Meaning the environment caused two separate lineages to evolve
similar traits to help organism survive, so they appear the same, but have different
origins.
a. Give some example (can you think of any on your own?)
Dolphins/Whales with stream line body and fins: these two have homologies with
each other ….HOWEVER the streamlined body and fins of a shark or fish are an
analogy compared to a whale/dolphin.
So the ability for these two groups to swim evolved separately….
6. What is a vestigial structure?
A functionless (does not serve a purpose) structure that an organism possess, but is
an important structure for a closely related species
a. Examples?
- Human tailbone
- Appendix
- Goose bumps
- Yolk sac
7. Who is Charles Darwin? What did he do?
Scientist who took trip around world. Collected thousands of plant and animals
species. Noticed in the Galapagos Islands that plants and animals were very similar
but not exactly the same to that of plants/animals in Ecuador. Observed finches in
Galapagos: found that there were many varieties that were very similar but had
differences primarily relating to feeding. i.e. beaks were different sizes/shapes.
Ultimately major influence in theory of evolution, natural selection and the idea of
organisms sharing common ancestors
a. How did Thomas Malthus influence Darwin’s thinking?
Realized that any species can produce many offspring and populations of any
species are limited by starvation, disease, competition, and predation. And only a
limited number of individuals survive to reproduce. Darwin reasoned that the
offspring of survivors inherit traits that help offspring survive and reproduce in their
environment Mainly, Malthus applied Darwin’s ideas of natural selection to humans
and helped Darwin realize that selective pressures exist for all organisms and that
all organisms that survive, survive because they all well adapted to their
environment.
b. What type of evidence (that is available today) did Darwin lack that
help support his theory
Darwin did not know how organisms inherit traits. He did not know that differences
in genes cause variation and some genes make an organism more likely to survive,
SO Darwin did not know about genetics and DNA
8. What is Natural Selection?
a. What are the four parts of natural selection?
- Overproduction: Producing more young than will survive
- Inherited Variation: Every individual is different but inherit traits from parents
- Struggle to Survive: Individual struggle to live and some traits help some
individuals to survive
- Successful Reproduction: Individuals best adapted to environment reproduce
and are likely to have offspring that survive and reproduce as well.
b. What does fitness mean?
The ability to survive and produce offspring who can also survive and reproduce
c. Why could the phrase “Survival of the fittest” also be “survival of the fit
enough” (philosophical question….means think about it)?
As long as an animal can survive long enough to reproduce than they are
considered fit. Meaning an organism might not be the strongest; it could have an
adaptation that makes it sneakier and steal mates of other stronger animals.
Example: crickets sometimes intercept female crickets on their way to a male
cricket who is chirping, the sneaky cricket waits near the male cricket that is
chirping and then meets up with the female before the loud chirping male. The
loud chirping male may also be eaten because it is chirping so loudly and attracts
a predator.
d. What did you learn in the peppered moth lab? The pom pom lab?
Peppered Moth: population number of light colored moths decreased while darker
moth population size increased. This was due to the industrial revolution and the
addition of soot to the atmosphere which began to darken the trees. The darker
moths that were once spotted more easily than the lighter moths by predators
were now better adapted to their environment and were caught less than the light
moths that were now more exposed.
Pom Poms:
- Learned definition of fitness
- Heritable: a characteristic which is influenced by genes and passed
from parents to offspring
- Evolution by natural selection takes place over many, many
generations
- Organisms are not capable of changing color, traits.
o Mutations (new traits) occur from the passing of genes from
parent to offspring (meaning that offspring are BORN with a
mutation)
- Natural Selection can not occur if there is NO variation in traits
9. What is selective breeding?
Human practice of breeding animals or plants that have certain desired
characteristics
a. Give some examples
- Breeding larger livestock, more resistant to disease, producing more milk, more
meet, producing more offspring
- Plants that produce sweeter fruit, larger fruit, resistant to frost, mold, etc
10. Examples of natural selection (review pages 122 – 123)
a. How is the example of the tuskless elephants an example of natural
selection?
b. Insecticide resistance
c. Male birds and colorful feathers
Tuskless elephants = not hunted, able to reproduce more
Insecticide resistance = don’t get killed by insecticide, able to reproduce, pass the
ability to resist insecticide on to offspring
Birds: More colorful, attract females, reproduce more easily
11. What is the difference between “absolute” and “relative” dating? (refer to
page 137 in text)
Absolute dating: Gives an age in years, uses the analysis of radioactive decay
Relative dating: estimating the age of rocks/fossils based on position in strata of
sedimentary rocks
a. Which type is more accurate? What do scientists examine for each
type of method?
Absolute is more accurate
12. List the Eras of the geologic time scale from earliest to most recent. YOU
MUST KNOW WHEN EACH ERA BEGAN AND WHEN THEY ENDED
Precambrian: 4.6 billion to 548 million years ago
Paleozoic Era: 543 million to 248 million years ago
Mesozoic Era: 248 million to 65 million years ago
Cenozoic Era: 65 million to present day
13. Precambrian Time
a. What type of gas did cyanobacteria put into Earth’s early
atmosphere? How did this gas change and in the upper atmosphere
and how did this benefit the rest of life on earth?
Cyanobacteria produced oxygen. Oxygen gas formed a new layer of gas in
atmosphere (ozone). Ozone absorbs radiation from the sun and allowed life that
had been restricted to water and underground to come on land.
14. Paleozoic Era
a. Greek meaning……”Ancient Life”?
b. Age of the “Invertebrates, Fish and Amphibians”
15. Mesozoic Era (meso) means “middle life”
a. Age of the Reptiles?
-
Flowering plants appear. Conifers dominate
Massive extinction of dinosaurs
16. The crater that lies on the coast of the Yucatan Peninsula in Mexico is said to
have been created by a large asteroid that impacted the earth over 65
million years ago (at the end of the Mesozoic era). Explain how this event
could have caused the mass extinction of the dinosaurs.
Asteroid impacts the earth and causes dust to cover earth’s atmosphere,
blocking out the sun. This cause drastic drop in temperature and kills many of
the plants on earth. Plants not around herbivores die, herbivores die, and
carnivores die. Additionally, once sun came through much of the heat was
trapped in because of gases in atmosphere, which caused temperatures to rise
very quickly and become excessively hot.
17. Cenozoic Era means “recent life”
a. Age of the “Mammals”?
- Rise of humans