Exam 1 Flashcards
According to current thinking, about when did the following occur?
a) The “Big Bang”
b) Formation of the Milky Way Galaxy:
c) formation of the solar system
a) ~ 13.8 bya
b) ~13.6 bya
c) ~ 4.5 bya
What name has been given to the earliest “Eon” in Earth’s history? Name 2 significant events that occurred during that Eon.
Hadeon -
- condensation of planet
- formation of moon
- heavy bombardment period
- formation of oceans
What name has been given to the second Eon in Earth’s history (from 3.8 to 2.5 bya)? Name 2 significant events that occurred during that Eon.
Archaean
- plate tectonics begins
- magnetic field established
- life arose
Why is the evolution of photosynthesis referred to as “The Great Oxygen Catastrophe”?
Bc oxygen is a highly reactive oxidizer that can break up large organic molecules. life had previously evolved in a reducing atmosphere, and oxygen would have been lethal to many organisms
What were listed in class as the 6 “key issues in the origin of life by chemical evolution”. Which is considered by most to present the greatest challenge for understanding?
- origin of small organic “building blocks”
- synthesis of large organic “macromolecules”
- origin of self-replicating nucleic acids/inheritance
- origin of catalytic enzymes/metabolism
- how #3 and #4 came together (considered most challenging)
- the origin of cell compartment
How many mass extinctions (not including a possible ongoing one) have there been during the Phanerozoic Eon? Which was the largest? Which one caused the extinction of the dinosaurs?
5; end - Permian; end - Cretaceous
about what percentage of the sunlight arriving at the Earth’s system actually reaches the ground surface?
~ 50 %
Why is the “Natural Greenhouse Effect” crucial for life on Earth?
it
1) raises the average temp ~ 32 C
2) dramatically decreases the change in temprature between day and night
What two reasons explain why the equator is more intensely heated than the poles?
Light at the poles:
1) has to travel through a greater thickness of atmosphere
2) is spread out over a greater area on the surface
What causes seasons to exist?
the 23 degree tilt of Earth’s axis
Explain briefly why there is heavy rainfall at the equator and arid areas at 30 degrees latitude
at 0 degrees –> rising heated air cools and loses water –> precipitation
at 30 degrees –> falling cool air warms and retains/ absorbs water –> no precipitation
What is the general pattern of ocean currents (gyres) in the Northern and Southern Hemispheres, respectively?
N –> clockwise circulation
S –> counter-clockwise circulation
briefly explain why deserts tend to be found on the west side of continents more than the east side.
- on W side –> cold water currents (with cold air) are moving toward the equator __> the air warms & retains/absorbs water –> thus no precipitation
- pattern goes other way on the E side
Why does buffalo, new york, get such large snowfalls in the winter?
lake effect snow from being on the east, downwind side of lake erie
List 5 mountain-related topographic effects on climate.
- altitude effects
- rain shadows
- slope effects
- valley effects
- N vs. S - facing slopes
what were the four major components of the “natural theology” view of life?
1) Earth & life are very young
2) All species were created as we see them now (unchanging)
3) All species have their place in the Scala Naturae
4) Organisms are perfectly adapted because created by a perfect “Divine Watch maker”
In Darwin’s logic in developing this theory of Evolution by Natural selection, what were the 5 - well-accepted facts from which he drew inferences?
1) All species have the potential to increase in population exponentially
2. Populations are never- the less pretty stable
3. “Necessities of life “are limited
4. Each individual has a unique combination of traits
5. Offspring tend to inherit their parent’s traits
Of the six theories said in class to be included in the Origin of Species, which is the one that is exemplified by the famous “Tree of Life” image? Which other one is the one that explains how organisms can come to be well adapted to their ways of life?
T.O.L. –> Common ancestry/ descent
Adoption –> N.S.
As the terms are used in science, explain the difference between a “Law” and a “Theory”
law –> a description of a repeatable, consistent, important pattern in nature
theory –> a well-thought-out general explanation, testable, for important patterns in nature
Briefly explain Darwin’s explanation for why Linnausus’ hierarchical system of classification is apparently the correct “natural system”
Linnaeus’ “shared” & “unshared” traits are traits shared due to common ancestry or recently derived changes in traits, due to species sharing ancestors in the “Tree of Life” with more recent or more ancient separation of species
What did Darwin say were the 3 steps that explain why there are different species in different places?
1) random dispersal
2) isolation
3) diversifying evolution
what are the two different forms of “chance dispersal”?
colonization & Vicariance
what are the six major types of fossils? which type is most common?
- intact
- compression
- casts
- permineralized (most common type)
- trace fossils
- micro fossils
explain the difference between a “homology” and an “analogy” in biology.
Homology –> similarity of the 2 species traits due to descent from a common ancestor with those traits
analogy –> similarity of 2 species traits due to a similar way of life (common ancestor not like that)
