Fossil record and First life

Question 1

What are the four requirements for life?

Answer 1

1: Metabolism
2: Response to stimuli
3: Homeostasis
4: reproduction with potential for error

Question 2

What is Metabolism?

Answer 2

a system of management of energy and materials via chemical reactions

Question 3

What constitutes a response to stimuli

Answer 3

Response can be changed in growth, in chemical, or movement.

Question 4

What is homeostasis?

Answer 4

Maintenance of some internal chemical and/or thermal consistency relative to variation outside of the entity

Question 5

Are viruses alive?

Answer 5

No, they lack metabolism and homeostasis and cannot reproduce without using the cellular machinery of the host cell.

Question 6

What is a fossil?

Answer 6

Is a preserved remnant/evidence of organisms that lived in the past

Question 7

What is a fossilis?

Answer 7

A fossil that is dug up, usually within sedimentary rocks

Question 8

What are distinct levels of rock called?

Answer 8

Strata

Question 9

Whether an organism or part thereof is fossilized depends a great deal on chance.
What chance?

Answer 9

• More likely if hard - than if soft bodied
• More likely if aquatic than terrestrial
• More likely if inshore marine than offshore.
• More likely of decomposing organisms absent after death.

Question 10

Based off of the fossil records, how complete is our knowledge of past diversity and distribution of life?

Answer 10

it is very biased and incomplete

Question 11

What are trace fossils?

Answer 11

Evidence of behaviors

• tracks
• burrows
• faeces

Question 12

The study of trace fossils is called?

Answer 12

Ichnology

- ichnos = track, trail

Question 13

What does Ichnos mean?

Answer 13

• ichnos = track, trail

Question 14

What are cast fossils?

Answer 14

A cast forms when minerals fill the space in sediment where organism decay after being berried

Question 15

What are petrified fossils?

Answer 15

fossils have had their tissues replaced by minerals

Question 16

What does Petra mean?

Answer 16

Rock

Question 17

Can you find fossilized organic material?

Answer 17

Yes you can:

Thin carbon films
In amber
In tar peat
Frozen

Question 18

What is a sub-fossil?

Answer 18

Fossil has most organic parts replaced by mineral; sub-fossil has high % organic matter.

Question 19

Relative dating is done via what method?

Answer 19

Sedimentary stratigraphy

Question 20

What does Stratum mean?

Answer 20

Layer

Question 21

What does Graph mean?

Answer 21

Write/record

Question 22

what is relative dating?

Answer 22

The process of seeing the age of fossils by using the principles of super position to determine age.

Question 23

Can sediments be moved or rearranged naturally?

Answer 23

Yes, through mass geological moments

Ie earth quakes

Question 24

True or false:

It is common to have gaps in Sedimentary sequence.

Answer 24

True

Due to erosion and/or a temporary stop in sedimentary deposition.

Question 25

What are widespread common index fossils?

Answer 25

Fossils that can help read incomplete or scrambled layers.

Question 26

What makes a good index fossil?

Answer 26

The best index fossils are those that existed form only a brief time but that made a wide geographic distribution at that time.

Question 27

How are geological time scales made?

Answer 27

Created based on the occurrence and disappearance of major taxa, including index fossils

Question 28

Why are geological time scales commonly linked with changes in eon, era, period, and epoch?

Answer 28

Becasue these time scales are often at the same time as major changes in taxa, due to the dependence on fossil record

Question 29

How do you determine the absolute age of different scales?

Answer 29

Radiometric dating

Question 30

What is radiometric dating?

Answer 30

It involves measurements of the radioactive isotopes in fossils or rocks. They decay at a fixed rate "half life" and based on the concentration of daughter element we can see how long the rock/fossil is.

Question 31

What is a isotope?

Answer 31

An element that can exist in many different states. | C12 C14

Question 32

What makes a isotope?

Answer 32

The difference in neutrons in the element.

Question 33

What is the most common element used in radiometric dating?

Answer 33

Carbon 14 - decays into nitrogen 14

Question 34

What is a half life?

Answer 34

when an radioactive element transmuted half of its mass into a daughter element. Due to radioactive decay

Question 35

Why and how do we use Carbon 14 for radiometric dating?

Answer 35

Plants take in C12 and C14 during photosynthesis Animals get the same ratio of C12 and C14 through eating plants or herabavours Once the organism dies they no longer take in C12 or C14 C12 stays but C14 decays

Question 36

What is the half life of Carbon 14

Answer 36

5730

Question 37

is carbon dating good for old or young fossils ?

Answer 37

Young | only good up to 75,000 years old

Question 38

What do we use for older fossils than 75,000 years old?

Answer 38

We use Uranium

Question 39

What is the half life of U-238?

Answer 39

4.5 Billion years old

Question 40

The location of fossil both in place and in time is important. What is the challenge with the "place" of fossils?

Answer 40

There is Continental drift, meaning land masses are not always in the same place or same environment.

Question 41

What was the first evedance of Continental drift?

Answer 41

Fossils within the same genus of plant found in Australia, Antarctica, and south america produced evedance for a Palaeo-Continent

Question 42

What was the name of the supposed Palaeo continent?

Answer 42

Gondwana

Question 43

What is Pangaea?

Answer 43

The Super Continent

Question 44

What are mass extinctions?

Answer 44

Sudden periods in which large numbers of species and higher taxa disappeared

Question 45

When was the end-Permain mass extinction?

Answer 45

It was around 245 million years ago

Question 46

What else happed during the end-permain mass extinction?

Answer 46

Pangaea was formed

Question 47

How many species and families died during the end-permain mass extinction?

Answer 47

60% of all families | 90% of all marine species

Question 48

When was the end-Cretaceous mass extinction?

Answer 48

65 million years ago. | at the Cretaceous-Paleogene boundary

Question 49

how many families went extinct during the cretaceous mass extinction?

Answer 49

20% of all families

Question 50

What are the two main theories that are held about the end-cretaceous mass extinction?

Answer 50

Some say that it was an asteroid or comet that caused it. Others say that it was more slow and gradual, and being caused by climate change. With the asteroid being the final straw.

Question 51

How long ago did earth form?

Answer 51

4.6 BILLION years ago

Question 52

What is the oldest fossil record evidence that we have uncovered

Answer 52

3.5 billion years old

Question 53

What was the first fossil record of?

Answer 53

Single celled prokaryotes that LACKED membrane bound organelles.

Question 54

How long were Prokaryotic cells the only evidence of life on earth?

Answer 54

1.5 Billion years

Question 55

Where are the oldest prokaryotic fossils found?

Answer 55

In stromatolites

Question 56

What is the definition of Stroma?

Answer 56

sheet

Question 57

What is the definition of Lith?

Answer 57

Rock

Question 58

How are banded rocks created?

Answer 58

- prokaryotes live on sediment - Sediment accumulated on top of them - Prokaryotes grow up through the sediment leaving layers

Question 59

When did oxygen begin to accumulate in the earths atmosphere, and what caused this?

Answer 59

It started to accumulate roughly 2.7 billion years ago. It was caused by photosynthetic cyanobacteria who used the suns energy to split water into hydrogen and oxygen

Question 60

What is another name for cyanobacteria?

Answer 60

Blue-green algae (even though they are not algea)

Question 61

What were the first oxygen markers that we could observe?

Answer 61

iron oxide percipated out and resulted in banded iron rock that we analyze today.

Question 62

True or false: | O2 was toxic to most early life on earth.

Answer 62

True. | It was the waste product.

Question 63

What are obligate anaerobes?

Answer 63

Species of prokaryotes that are adapted to survive in a low oxygen environment

Question 64

What are prokaryotes that are adapted to oxygen rich atmospheres and began respiring______

Answer 64

Aerobically

Question 65

up until the 1800's what was the primary theory of how life began?

Answer 65

Spontaneous generation: | ie - life just kinda appeared

Question 66

in more recent time we have been able to replicate earths early conditions, producing amino acids, although these cannot act like cells. What is the current explanation?

Answer 66

Spontaneous formation of hollow lipid vesicles

Question 67

Experiments conducted found that vesicles form faster in the presence of ___________, a type of ________ thought to be common 4 billion years ago

Answer 67

Montmorillonite volcanic clay

Question 68

Where did scientist first think life started?

Answer 68

In shallow water bodies that are exposed to atmosphere.

Question 69

Where do scientist now think life first started?

Answer 69

They think it arose near or around hot, mineral-rich deep sea vents

Question 70

What is the Panspermia hypothesis?

Answer 70

That prokaryotes came from space on a comet

Question 71

What does pan mean?

Answer 71

Everywhere

Question 72

What does sperm mean?

Answer 72

Seed

Question 73

the Panspermia theory gained traction in the 1990's when they found _____ structures looking like bacteria inside of a meteorite

Answer 73

Nanobes

Question 74

What has been discovered in meteorites that gives some credit to the panspermia theory?

Answer 74

Amino acids

Question 75

What is (as far as we know) the most important step in fostering early life?

Answer 75

free, non-toxic water