Topic 9

Question 1

What does an entity need to be considered alive?

Answer 1

Organization, metabolism, response to stimuli, homeostasis, adaptation, and reproduction

Question 2

Are viruses alive?

Answer 2

Viruses are infectious parasitic entities that span the boundary between living and non-living.

Viruses have nucleic acids that replicate, mutate, and respond to natural selection, but LACK metabolism, homeostasis, and cannot reproduce outside of the host cell

Question 3

3 Eons of geologic Record

Answer 3

Archaean, Proterozoic, and Phanerozoic

Question 4

Phanerozoic

Answer 4

The last half billion years encompassing multicellular eukaryotic life.

3 eras: plaeozoic, mesozoic, and cenozoic

Question 5

Factors for an Organism to undergo Fossilization

Answer 5

Existed for a long time
Abundant and widespread
hard rather than sof-bodied
aquatic
inshore marine, not offshore
not a decomposing organism

Question 6

Mold Fossils

Answer 6

Form when a hollow space (impression) remains after the organism decays or resolve. Ex: cast fossils creating a mold

Question 7

Replacement/Petrified fossils

Answer 7

The original tissues of the organism are replaced by minerals, preserving the detailed structure of the organism

Question 8

Trace Fossils

Answer 8

Provide evidence of organism’s behaviour, such as tracks, burrows, or feces

Question 9

Preserved Fossils

Answer 9

retain much of the original organic material of the organisms, such as carbon films, amber, tar or peat, or being frozen

Question 10

Sedimentary Strata

Answer 10

Layers (strata) revealing the relative ages of fossils but not the absolute ages.

Question 11

Challenges to Relative Dating

Answer 11

Common to have gaps in sedimentary sequence

Sediments can be tipped or even inverted by makor land movements

Question 12

Radiometric Dating

Answer 12

Absolute dating of fossils using radioactive decay of isotopes of various elements providing a means to an age

Question 13

Plate Tectonics Theory

Answer 13

considers that the Earth’s crust is composed of large plates that have been slowly moving since about 3.4 billion years ago causing continental drift to impact Earth’s biodiversity and the distribution of fossils

Question 14

Supercontinent name

Answer 14

Pangaea
250 million years ago

Question 15

“Big Five” Phanerozoic mass extinctions and main 2 examples

Answer 15

mass extinctions where 50% of the Earth’s species became extinct.
1. Permian extinction
2. Cretaceous extinction

Question 16

Permian mass exctinction

Answer 16

Defines the boundary between the Palaeozoic and Mesozoic eras 252 million years ago caused by volcanic activity and coincided with the formation of Pangaea

Question 17

Cretaceous mass extinction

Answer 17

66 million years ago, separating the Mesozoic from the Cenozoic. About 20% of all families went extinct, many being terrestrial plants and animals. Lost non-avian dinos.
Coincides with worldwide geologic deposits from a meteorite impact at Chicxulub, Mexico

Question 18

Holocene extinction

Answer 18

Probable human-caused mass extinction ongoing now as a result of human population growth and overconsumption of natural resources

Question 19

Consequence of mass extinctions

Answer 19

Lost of biodiversity altering ecological communities and niches available for organisms. Entire lineages can be lost by mass extinctions

Question 20

Adaptive radiation

Answer 20

The rapid evolution of diversely adapted species from an ancestral species occurring when a change in the environment makes new niches available.

Question 21

Causes of Adaptive Radiation

Answer 21

Mass extinctions, evolution of novel characteristics, and colonization of new regions with little competition

Question 22

When did the Earth form?

Answer 22

Approximately 4.6 billion years ago during the Hadean Eon

Question 23

Early Earth Conditions (first billion years)

Answer 23

Unstable crust floated on molten magma as earth cooled

Question 24

Early Earth Conditions (first billion years)

Answer 24

Unstable crust floated on molten magma as earth cooled, steaming gases formed an atmosphere without oxygen, and when temperature dropped, water vapour condensed into raid which collected in basins

Question 25

How did life begin?

Answer 25

Life originated from a series of chemical reactions that led to the formation of living organisms

Question 26

Chemical and physical processes on early Earth that le tot the formation of simple sells

Answer 26

1. Abiotic synthesis of small organic molecules 2. Polymerization of small organic molecules into organic polymers 3. Formation of protocells 4. Emergence of self-replicating molecules

Question 27

2 Possible Sources of organic molecules on Early Earth

Answer 27

1. Terrestrial orgins: spontaneous osynthesis driven by energy sources 2. Extraterrestrial origins: objects hit earth

Question 28

Miller-Urey Experiment (1953)

Answer 28

Demonstrated the amino acids could be synthesized by simulating early Earth conditions. It showed methane, ammonia, hydrogen, and water vapour when exposed to electric sparks could form organic molecules in reduced atmospheres

Question 29

How did polymerization of small organic molecules to larger ones occur?

Answer 29

Likely occurred on hot surfaces such as clay, sand, or rock, where evaporation of water concentrated small organic molecules, triggering the spontaneous formation of organic polymers

Question 30

Protocells

Answer 30

simple, cell-like structures that form when organic molecules become enclosed within vesicles. hypothetical precursors to modern cells.

Question 31

RNA World Hypothesis

Answer 31

Idea that suggests RNA, not DNA, was the first self-replication molecule. Simpler than DNA, it can still self-replicate and perform catalysis (acting like enzymes to speed up chemical reactions

Question 32

Prokaryotes

Answer 32

The oldest fossil evidence of life hypothesized to have existed up to 3.9 bya Single-celled organisms with DNA not contained in the nucleus and lacking membrane-bound organelles.

Question 33

Domains of Prokaryotes

Answer 33

Bacteria and Archaea

Question 34

Stromatolites

Answer 34

The oldest known fossils, rocks formed by the accumulation of sedimentary layers of prokaryote species in shallow marine environments

Question 35

Great Oxygenation Event (GOE)

Answer 35

When oxygen began accumulating in the atmosphere and oceans, dramatically altered Earth’s environmental and caused the extinction of many prokaryotic groups 2.7 to 2.3 bya because prokaryotes has an anaerobic metabolism.