Umm

Question 1

What was earth’s first atmosphere like?

Answer 1

Almost all hydrogen and helium and they were very hot so they escaped earth’s atmosphere.

Question 2

What was Earth’s second atmosphere?

Answer 2

ots of volcanic activity, so there was CO2, water vapor (formed clouds), and ammonia. Carbon dioxide dissolved into the oceans and simple bacteria thrived off of the sun and carbon making oxygen.

Question 3

3rd atmosphere?

Answer 3

Our current atmosphere, made up of 78% of nitrogen, 21% oxygen, and 1% trace gasses. Plants and animals can thrive in these conditions.

Question 4

*What is cyanobacteria?

Answer 4

Algae that was the first thing that photosynthesize.

Question 5

What is paleontology?

Answer 5

the study of the history of life on Earth as based on fossils

Question 6

When was the first evidence of life?

Answer 6

4.3 billion years ago

Question 7

When did the first animal appear?

Answer 7

2.5 billion years ago

Question 8

What was the Cambrian radiation “explosion”?

Answer 8

First modern day animals

Question 9

What fossils are found in Virginia?

Answer 9

Paleozoic- marine, mesozoic- dinosaur, Cenozoic- mammals, carnivores.

Question 10

Place the organisms in geologic time order of appearance: Algae, Bacteria, Bird, Fish, Reptile, Human

Answer 10

1. Bacteria 2. Algae 3. Fish 4. Repitle 5. Bird 6. Human

Question 11

What is radioactive dating?

Answer 11

Absolute age of fossils shown through radioactive decay.

Question 12

What is a daughter isotope?

Answer 12

What the decaying particles are turning into

Question 13

What is a half-life?

Answer 13

The time it takes for half of the particles to decay.

Question 14

Carbon dating:

Answer 14

dating organic matter found within the rock

Question 14

Carbon dating:

Answer 14

dating organic matter found within the rock

Question 15

What is absolute age?

Answer 15

Numerical number for the age of fossil

Question 16

What are beds?

Answer 16

Sedimentary rock layers.

Question 17

Bedding planes-

Answer 17

Boundaries between beds

Question 18

Relative age-

Answer 18

Age of an object relative to the age of objects around it- not numerical

Question 19

Law of superposition-

Answer 19

Youngest rock is at the top, oldest is at the bottom

Question 20

Law of original horizontality

Answer 20

Rock layers left undisturbed will stay horizontal

Question 21

Unconformity-

Answer 21

Missing piece in geological history- weathering, erosion, ect.

Question 22

Law of crosscutting-

Answer 22

A fault or igneous intrusion is always younger than the rock layers it cuts through

Question 23

Radiometric Dating:

Answer 23

comparing the relative percentages of a radioactive (parent) isotope and a stable (daughter) isotope

Question 24

Isotopes

Answer 24

same element but different numbers of neutrons

Question 25

Trace fossils:

Answer 25

a fossilized mark that formed in sedimentary rock by the movement of an animal on or within soft sediment(burrows)

Question 26

Index fossil-

Answer 26

Fossil that shows the exact age of a layer. Short lived, widespread, adaptable, easily recognizable.

Question 27

Types of trace fossils?

Answer 27

Footprints, burrows, and tracks

Question 28

Molds

Answer 28

empty cavities of organisms

Question 29

Casts

Answer 29

the empty cavities are filled with sand or mud