Topic 6

Question 1

What are strata?

Answer 1

Distinct layers of rock that usually have fossils

Question 2

What are things that increase the likelihood of an organism becoming a fossil?

Answer 2

If its hard, aquatic, inshore marine and decomposing organisms are absent

Question 3

What is relative dating?

Answer 3

Dating based off of stratum, can’t tell how old a fossil is but can see the order of fossils

Question 4

What is absolute dating?

Answer 4

Radioactive isotopes in fossils or rocks. Decay of one isotopic form to another at a constant rate. We see how much of each type of something there is left, like how much carbon 14 is left and how much nitrogen 14 there is

Question 5

What is a half-life?

Answer 5

50% of atoms in a given amount of radioactive substance have decayed

Question 6

What is continental drift?

Answer 6

Land masses are “floating” on lava mantle and have moved over time. There are a bunch of tectonic plates and the boundaries are volcanoes or mountains

Question 7

What are the consequences of continental drift?

Answer 7

Changes to the environment and climate which can provide opportunities for diversification of life and mass extinctions which an also help diversify

Question 8

When did life begin?

Answer 8

Stromalites from 3.5 billon years ago seem to have contained life as the resemble current mats of microbes. But some Canadian rocks show evidence of life 3.95 billion years ago

Question 9

How did life form? What are the 4 steps?

Answer 9

Abiotic seethes of organic molecules, abiotic synthesis of macromolecules, formation of protocells and self-replicating molecules

Question 10

What is step 1?

Answer 10

Abiotic synthesis of organic molecules. Inorganic atmospheric gases had a lot of energy applied and underwent abiotic synthesis. They became things like sugars, lipids, nitrogenous bases and amino acids

Question 11

Where was the energy from in step 1?

Answer 11

Lightning, deep sea thermal vents and the heat of asteroids colliding

Question 12

What is step 2?

Answer 12

Abiotic synthesis of macromolecules. Amino acids, nitrogenous bases and sugars become proteins, enzymes and nucleic acids

Question 13

Where would step 2 take place?

Answer 13

Hot sand, clay or rock

Question 14

What is step 3?

Answer 14

Formation of protocells. Spontaneous formation of cell like vesicles which resemble living cell membranes. This would have been able to export own products

Question 15

Where did step 3 take place?

Answer 15

Most likely in volcanic clay

Question 16

What is step 4?

Answer 16

The first nucleic acids. RNA was the first genetic material

Question 17

Why was RNA the first genetic material instead of DNA?

Answer 17

RNA is self replicating, can form different shapes based on environment, can catalyze its own reactions and is favored by natural selectin? DNA would have needed support from other molecules that didn’t exist at the time

Question 18

Where did life originate?

Answer 18

Hot, mineral-rich deep sea vents

Question 19

Is the order of the steps accurate?

Answer 19

We do not know if protocells were formed first or if the first nucleic acids were formed first. Steps 3 and 4 are interchangeable