Download Name Period - ehs-honors-biology

Name _________KEY__________________________ Period _____ Date __________
Review Packet: Origins of Life and Evolution
For this test, you should study from your class notes, all handouts, class activities
(why did we do them, and what did you learn?), and the readings from the
textbook (Chapter 14).
Some Major Topics/Handouts in Origin of Life and Evidence for Evolution
 Origins webquest and the Early Earth
 Darwin’s Voyage
 Beak of a Finch lab, Jelly Bean evolution lab, Natural Selection “Bug”
Camouflage simulation
 “Understanding Natural Selection” worksheet
 Evidence of Evolution video
 Evidence for Evolution - Stations Activity
 Evolution of Human Skin Color articles
 Obesity epidemic / Weight of the Nation / Thrifty gene hypothesis
Review Questions
1. When was the universe formed? The Earth? When did life on Earth first arise?
Universe: 13.7 billion years ago (Big Bang)
Earth: 4.6 billion years ago
First life (bacteria): 3.8 billion years ago
2. What were the conditions like on the early Earth?
Atmosphere contained carbon dioxide, methane, hydrogen sulfide, and ammonia
gases (no oxygen gas). Lots of lightning and volcanic activity. Surface bombarded by
meteors.
3. How did oxygen begin to accumulate in the atmosphere?
Photosynthetic cyanobacteria produced oxygen as a waste gas. These bacteria first
appeared and spread across the globe somewhere between 2.8-3.5 billion years ago, as
evidence by fossils of stromatolites.
Hon. Biology, Mr. Hammer, 2013
Page 1 of 4
4. Explain the influence of each of the following people on Charles Darwin:
a. Captain Robert FitzRoy – Captain of HMS Beagle, the ship on which
Darwin traveled around the world from 1831-1836 and recorded many
observations on Earth’s history and living things.
b. Charles Lyell – Author of Principles of Geology. Argued that Earth was
much older than previously thought and that Earth has been constantly
changing throughout its history.
c. Thomas Malthus – Economist who wrote about growth rate of human
population and predicted that overpopulation would lead to competition for
resources and ultimately famine and sickness.
d. Alfred Russel Wallace – British naturalist who independently came up with
the theory of natural selection. Published his work at the same time as Darwin.
5. Explain how Darwin’s voyage on the HMS Beagle led to his formation of the
theory of natural selection.
Darwin’s observations confirmed several of his beliefs, including the idea that Earth
has been constantly changing over time and that similar changes can be found in
living species. In particular, Darwin was impressed by the similarities between
animals on the Galapagos Islands and those on the South American mainland some
500 miles of ocean away.
6. Explain Darwin’s theory of evolution by natural selection.
a. Variation - individuals within a population possess heritable variation within
traits
b. Overproduction - organisms produce more offspring than can survive
c. Competition - those individuals with advantageous adaptations will outcompete others
d. Differential Survival - individuals with favorable characteristics tend to
survive more
e. Differential Reproduction - individuals with favorable characteristics tend to
have more offspring & pass on these traits to their offspring
 Over time, the frequency of favorable traits increase in the
population
Key distinction: Individuals are selected, but populations evolve
Hon. Biology, Mr. Hammer, 2013
Page 2 of 4
7. What is meant by “survival of the fittest?”
Individuals in a population with adaptations that provide an advantage in
competition will be more likely to survive and reproduce, thereby passing on their
favorable traits to the next generation.
Warning: This phrase is misleading because an individual doesn’t have to be the
“fittest” to prevail in natural selection…they simply need to be “fit” enough to
reproduce.
8. What is an adaptation? Give at least two examples of how color can be an
adaptation.
An adaptation is an inherited characteristic or trait that increases an individual’s
likelihood of surviving and reproducing. Adaptations involving color include
camouflage and mimicry.
9. How does the fossil record provide evidence of evolution?
The fossil record suggests that life has evolved from a handful of simple organisms at first
and then new, more complex organisms appearing over time. The characteristics of newer
organisms frequently appear to be modified forms of characteristics of older organisms.
Though there are gaps in the fossil record and some unusual occurrences, the overall
picture created by the fossil record is one of consistent, incremental development that can
only be explained by evolution through natural selection.
10. How do living things provide evidence of evolution? In your answer, discuss
comparative anatomy (homologous, analogous, and vestigial structures),
embryology, and biogeography.
Comparative anatomy – Homologous structures (structures which have the same
form but different uses) provide evidence of divergent evolution and suggest a recent
common ancestor. Examples include a human forearm and a bat wing. Analogous
structures (structures which evolved from different origins but function similarly)
provide evidence of convergent evolution in response to similar environmental
pressures. Examples include a bird wing and a bat wing. Vestigial structures are
structures that have no present function but provide evidence for evolution. Examples
include the human tailbone and appendix (both were used by the ancestors of humans
but have no current function).
Hon. Biology, Mr. Hammer, 2013
Page 3 of 4
Embryology – Organisms that are closely related undergo similar stages of
embryological development. Developmental patterns also reveal evolutionary
relationships. For example, the fact that human embryos and those of all four-limbed
vertebrates have pharyngeal gill slits for a short period during development is
evidence of a shared ancestor.
Biogeography – The drifting of the continents caused species to be geographically
isolated and lead to climate changes affecting the survival and evolution of species in
various parts of the world. For example, all flightless birds (penguins, ostriches, emus)
are found in the Southern hemisphere because they share a common ancestor that
evolved on the Southern supercontinent after the split of Pangaea.
11. What is the difference between divergent and convergent evolution?
Divergent evolution – Process by which new species form from an existing
population or species, usually because a population occupies a new
habitat/environment in which different variations are favored by natural selection.
Convergent evolution – Process by which organisms evolve similar adaptations
(analogous structures) despite having dissimilar or unrelated evolutionary ancestors.
12. How does biochemistry provide evidence of evolution?
The more similar the DNA or amino acid sequence, the more closely related the
species.
We can make this claim because DNA and the proteins it codes for are passed down
from parents to offspring during reproduction. So, species that share a common
ancestor will have inherited that ancestor’s DNA.
13. Explain the evolution of human skin color.
Darker skin tones (more melanin) provide better protection against UV destruction of
folate in blood. Lighter skin tones (less melanin) make it easier to make sufficient
vitamin D, an important molecule for bone and immune health. As early humans
migrated from equatorial Africa to other parts of the world, certain skin tones
provided reproductive advantages based on latitude (intensity of sunlight). This is
why darker skin tones are more popular in equatorial regions while lighter skin tones
become increasingly popular as you approach the poles.
Hon. Biology, Mr. Hammer, 2013
Page 4 of 4
14. How do new species evolve? Explain and give an example.
Living things change over time through the process of natural selection. When
natural selection acts on reproductive traits and populations within a species
accumulate so many differences that they can no longer reproduce with each other, we
now refer to these populations as being separate species.
For example, consider Darwin’s finches in the Galapagos Islands. One species of finch
on the mainland arrived at the islands by storm. On each island, natural selection
favored finches that had favorable traits (beak size/shape matching available food),
causing the finch populations on the islands to become increasingly different from
each other. Over time, the populations became so different that they lost the ability to
interbreed, resulting in the formation of 13 finch species.
15. Explain the difference between gradualism and the punctuated equilibrium
theories of evolution.
http://bioap.wikispaces.com/file/view/gradualism.gif/94608242/gradualism.gif
Gradualism – slow changes over time throughout history
Punctuated equilibrium – long periods of no change interrupted by brief periods of
rapid evolution and speciation.
Hon. Biology, Mr. Hammer, 2013
Page 5 of 4