Topic 6

Question 1

What year was the origin of the earth?

Answer 1

4.5 bya

Question 2

how old are the oldest prokaryotes?

Answer 2

3.5 mya

Question 3

how old are the oldest eukaryotes?

Answer 3

1.5 bya

Question 4

the first multicellular organisms arose…

Answer 4

1.2 bya

Question 5

what are the benefits and costs of multicellularity?

Answer 5

• Allows for cellular specialization
  -size

Question 6

What are the benefits of the size of a cell?

Answer 6

Bigger = better
larger means that there is a lower SA to V ratio - it is easier to maintain homeostasis
BUT …. most cells are microscopic … why?

Question 7

what is the average cell size?

Answer 7

1-100 um

Question 8

why do cells need to be small?

Answer 8

smaller= more efficient/faster
more efficient - to obtain raw materials and rid of waste

Question 9

I thought that bigger = better, so why are cells microscopic? how do we fix this?

Answer 9

• we take a bunch of small and put them together = still efficient and have a small SA to V ratio

Question 10

what are the benefits of multicellularity?

Answer 10

large size
autotrophs
heterotrophs

Question 11

why is being an autotroph beneficial?

Answer 11

• optimizes conditions for growth and reproduction

Question 12

why is being a heterotroph beneficial

Answer 12

• more prey species are heterotrophs - less predators

Question 13

What are the costs of being multicellular?

Answer 13

• high metabolic costs
• increased generation time

Question 14

Explain the Colonial model of evolution of multicellular eukaryotes

Answer 14

• multicellular eukaryotes evolved when cells of same species gathered into colonies, the cells differentiated and evolved into multicellular eukaryotes
• colonies gave rise to division of labor - which allowed distinction among cells

Question 15

what did colonies do in the colonial model of the evolution of multicellular eukaryotes

Answer 15

• gave rise to the division of labor, leading to structural and functional distinction among cells

Question 16

how were lineages of algae fungi plants and animals produced?

Answer 16

• multicellularity evolved several times

Question 17

in what animal phylum are cells not grouped into tissues?

Answer 17

porifera
- they also have a non-motile filter feeder with a small # of specialized cells

Question 18

phylum porifera is at the what level of organization? why?

Answer 18

cellular
because they do not join to form tissues

Question 19

what is bio diversity?

Answer 19

the variety of life in the world or in a particular habitat or ecosystem

Question 20

what two factors determine biodiversity?

Answer 20

speciation and extinction
- some say extinction plays higher role

Question 21

Extinctions are naturally balanced by the _______________ of __________. this is why there is still life on earth today

Answer 21

formation of new species

Question 22

speciation

Answer 22

the birth of a species
- evolution of reproductive isolation within ancestral species - results in 2 descendant species

Question 23

extinction

Answer 23

the death of a species
last existing member of a species dies

Question 24

Background extinction

Answer 24

a long lasting rate at which taxa become extinct
- it is always slowly happening

Question 25

mass extinction

Answer 25

a highly elevated rate of extinction, extends over a relatively short geological interval

Question 26

what is the general geological time scale? from longest to shortest

Answer 26

eon - era - period - epoch

Question 27

what are the eons in order of longest ago to most recent?

Answer 27

Hadean Archaean Proterozoic phanerozoic

Question 28

describe the Hadean Eon

Answer 28

4.6-3.85 bya the formation of the earth - crust, atmosphere, oceans

Question 29

describe the Archaean eon

Answer 29

3.85-2.5 bya origin of life evolution of prokaryotes oxygen begins to accumulate in atmosphere

Question 30

describe the Proterozoic eon

Answer 30

2.5bya -542 mya eukaryotes arise multicellularity

Question 31

describe the Phanerozoic eon

Answer 31

542 mya - present diversity of plants and animals

Question 32

when was the cambrian explosion?

Answer 32

545-488mya

Question 33

what are the order of eras? oldest to most recent

Answer 33

Paleozoic, Mesozoic, Cenozoic - they are all in the phanerozoic eon

Question 34

what is the order of the periods? oldest to most recent

Answer 34

Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleogene, Neogene, Quaternary

Question 35

how many periods are there?

Answer 35

12

Question 36

what is the Cambrian explosion?

Answer 36

- a speciation event - all but one of the animal phyla dramatically appear

Question 37

what happened in the cambrian explosion?

Answer 37

new modes of moving - swimming, climbing, burrowing first segmented body plans - a diversity of them too - notochord, external skeletons, appendages

Question 38

what were 3 things that lived during the cambrian period?

Answer 38

anomalocaris trilobits leanchoilia

Question 39

why did the Cambrian explosion happen? - Name the 3 factors and explain

Answer 39

1. environmental - inc. in oxygen levels = higher metabolism and growth 2. developmental - evolution of Hox genes that allowed developmental flexibility - lead to minor modifications 3. Ecological - Predator-prey arms race - change in exoskeleton/locomotory organs

Question 40

what are the 5 major mass Extinctions?

Answer 40

Ordovician Devonian Permian Triassic Cretaceous

Question 41

what was the Carboniferous period like?

Answer 41

cold - finite resources

Question 42

what happened in the Ordovician Extinction period?

Answer 42

86% species lost

Question 43

What happened in the Devonian Extinction?

Answer 43

75% of species lost - Jawed vertebrates, land vertebrates, etc.

Question 44

What happened in the Permian Extinction?

Answer 44

60% all families gone 90% of all marine species

Question 45

What happened in the Triassic Extinction?

Answer 45

80% species lost

Question 46

What happened in the Cretaceous Extinction?

Answer 46

20% of all families lost dinosaurs lost - but not birds

Question 47

what is the proposed new epoch called?

Answer 47

Anthropocene

Question 48

When did life on earth appear?

Answer 48

3.8 bya