Antiquity of Life

Question 1

How old is the Earth?

Answer 1

Our own solar system formed 4.55-4.56 billion years ago.

Our universe is about 13.7 billion years ago

Question 2

What was Primitive Earth’s atmosphere consisted of?

Answer 2

Methane, ammonia, water vapor, and a negligible amount of free oxygen

Question 3

To oxidize substances means?

Answer 3

To remove one or more electrons from an atom, ion, or molecule

Question 4

The early atmosphere was highly reducing means?

Answer 4

capable of gaining electrons and forming more complex molecules

Question 5

Autotrophs

Answer 5

An organism capable of making its own food from inorganic sulfur and iron compounds

Question 6

Heterotrophs

Answer 6

Consuming organic molecules

Question 7

Continental drift

Answer 7

The continents are constantly rearranging themselves

Question 8

Plate tectonics

Answer 8

Movement of large plates of Earth’s crust due to activity at spreading centers and subduction zones.

Question 9

When first organisms appeared on earth?

Answer 9

3.5 billion years ago

Question 10

Four great eras of the geological time scale

Answer 10

Precambrian (oldest), Paleozoic, Mesozoic, and Cenozoic (we are in the Quaternary period of Cenozoic era)

Question 11

Dating Fossil:
Relative Dating
Absolute Dating

Answer 11

RD: Deeper sedimentary layers formed earlier and their fossils are older than those found in shallow layers of rock
AD: Radiometric dating dendrochronology and racemization

Question 12

Archaea

Answer 12

One of three major domains that contains more simple cells (prokaryotes)

Question 13

Dendrochronology

Answer 13

A type of absolute dating technique that relies on the fact that trees have annual growth rings that reflect the age of the tree (one ring is produced each year).

Question 14

Eukarya

Answer 14

One of three major domains that contains complex cells with a nucleus and an array of organelles that perform different functions within the cell (eukaryotes).

Question 15

Eukaryote

Answer 15

Member of the Eukarya that have complex cells with a nucleus and an array of organelles that perform different functions within the cell.

Question 16

Fossil

Answer 16

Preserved remnants of organisms (e.g., bones and teeth) or whole organisms embedded in amber, acid bogs and tar pits, or anywhere bacteria can’t decompose a dead body. Fossils can be found in other forms such as an animal’s footprint.

Question 17

Geological time scale

Answer 17

classification of different periods in Earth’s history that is used to divide fossils into age groups. Four great eras of the geological time scale are Precambrian, Paleozoic, Mesozoic, and Cenozoic eras.

Question 18

Heterotroph

Answer 18

An organism unable to make its own food, and therefore must consume organic molecules to gain energy.

Question 19

Half-life

Answer 19

A radioisotope’s half-life is the amount of time it takes for one-half of the parental atom population to decay into daughter atoms.

Question 20

Isomer

Answer 20

Isomers are compounds with the same formula, but each of them have a different arrangement of atoms in the molecule and different properties.

Question 21

Isotope

Answer 21

Isotopes of an element have the equal numbers of protons, but different numbers of neutrons. Different isotopes have different, but predictable stabilities. Radioactive isotopes’ nuclei decay at predictable rates (unique for each isotope) and give off energy and atomic particles.

Question 22

Pangaea

Answer 22

The supercontinent from about 250 million years ago where all of the landmasses were joined. Pangaea did not start to break apart until about 180 million years ago.

Question 23

Prokaryote

Answer 23

Any of the typically unicellular microorganisms that lack a distinct nucleus and membrane-bound organelles

Question 24

Reduction

Answer 24

A chemical reaction that involves the gaining of electrons and therefore lowering the oxidation state of the element that gains electrons.

Question 25

Sedimentary rock

Answer 25

Sedimentary rock is formed by layers of minerals that settle out of water build up and packed over time and is the best source of fossils. Each stratum, or layer, of sedimentary rock represents a particular period in Earth’s history and is characterized by a collection of fossils of organisms that lived at that time.

Question 26

Carbon-14 decays into

Answer 26

Nitrogen-14

Question 27

Dendrochronology is especially useful when estimating

Answer 27

relatively recent climate patterns

Question 28

According to the evidence for the early chemical evolution of life, the atmosphere on early Earth was highly reductive because it was lacking which of the following key molecules?

Answer 28

oxygen.