1st Midterm pt 3

Question 1

What is evolution? Why is it considered a scientific theory? How is this different from a “hunch”- or “guess”-type theory?

Answer 1

> Evolution:

• Descent with modification, by means of natural selection.
• A change in gene frequencies through time.
• It is considered a scientific theory because it is the systematic attempt to provide a natural explanation of how species undergo genetic change through time
• This is different from a hunch or guess type theory because evolution…is a fact, species undergo genetic change through time…and is a theory, a systematic attempt to provide a natural explanation for how species undergo genetic change through time.

Question 2

Who first proposed evolution by means of natural selection? On what observations did he (or they) base his (or their) theory?

Answer 2

• Charles Darwin.
• Noted that many species living on the continent were more closely related to extinct forms than species on other continents.
• if animals are well-adapted to their surroundings, and if poorly adapted animals will not survive long, and if the earth is very old, and if the earth has changed dramatically through time, THEN ANILMAS MUST HAVE CHNAGED TRHOUGH TIME AS WELL.

Question 3

What are the components of evolution? At what level - individual, population, species, etc. - does evolution work?

Answer 3

(See PowerPoint slides)
-we should see gradual change in animal anatomy through time, see evidence of new species forming from older species, evidence of transitional forms between groups of organisms, see that living organisms are related, having shared a common ancestry, and we should see natural selection work.
Mutation, recombination, reproduction, adaption, speciation, natural selection

Question 4

What does the scientific theory of evolution explain? What does it not explain?

Answer 4

The scientific theory of evolution by means of natural selection is supported by evidence from paleontology, from anatomy, from embryology, from organismal biology, from biogeography, from genetics, from molecular biology, and from systematics. The theory is also highly predictive.

Question 5

What supporting evidence for evolution is now available to us?

Answer 5

we should see gradual change in animal anatomy through time, see evidence of new species forming from older species, evidence of transitional forms between groups of organisms, see that living organisms are related, having shared a common ancestry, and we should see natural selection work. All have been met.

Question 6

Why is an understanding of evolution and how it works so important in environmental sciences?

Answer 6

Evolution is helping us make advances in biology and in modern medicine.

• It helps explain the past, extinction, and what to expect in the future.
• It also shows the possible consequences of human behavior within the environment.

Question 7

What is exponential growth? How does it differ from arithmetic growth?

Answer 7

1. Arithmetic growth
   - maintains amount/ amount is the same
   - long progression
2. Exponential (Geometric) Growth
   - maintains the rate

Question 8

What is Malthusian growth? (After whom is this kind of growth named?) What is irruptive growth? What is logistic growth?

Answer 8

-Named after Thomas Malthus, Malthusian growth explains “boom-bust”, that a population (with necessary resources) will grow rapidly until it is out of resources when it will begin to die out until the necessary resources have a chance to grow back, and then it will continue the boom-bust cycle.
→ Irruptive growth→ growth pattern over time, defined by population explosions and subsequent sharp population crashes, or diebacks
→ Logistic growth: changes in population size that follows a predictable repeatable S-shaped trajectory

Question 9

What are “pioneer species”? What growth patterns do these species show, and under what conditions?

Answer 9

Pioneer species: are hardy species which are the first to colonize previously disrupted or damaged ecosystems. They show boom bust cycle patterns “irruptive”

Question 10

What were some behaviors inferred for the earliest hominids? (As discussed in class.) How did these behaviors change through geologic time?

Answer 10

-Ate plants, possibly hunted? They scavenged! Made tools of shard rocks. Used stone tools, Hunted and gathered, went from being nomadic to not: turned agricultural, we did not have to move around for food, settled down, owned plants/land, grow new resources when current resources were used up, had more sex, more babies, more food, using resources like never before and needed more space.