Early Diversification: in the seas

Question 1

issues with comparison of phenotypic traits (fossil records)

Answer 1

• Local environment influenced phenotypes
• The fossil record is patchy and difficult to trace
• Some fossils we find are simply unclassifiable
• There is an extremely small chance of discovering fossils, and an even smaller chance they’re in good shape or even recognizable at all.

Question 2

bacteria

Answer 2

only group with a rigid cell capsule protecting cell membrane

Question 3

archaea

Answer 3

only organisms capable of methanogenesis

Question 4

eukaryota

Answer 4

only domain where all individuals require O2 to respire organic matter as a source for cellular respiration

Question 5

Stromatolites

Answer 5

-fossils in sedimentary rocks that suggest a large presence of bacterial “mats: during the archaean.

this provided ideal envr for prokaryotes with different metabolisms to compete and interact with mutual benefits (symbiotic relationship)

Question 6

horizontal gene transfer

Answer 6

-transfer of genetic material to another cell that is not your offspring, very common in prokaryotes

Question 7

Microbial Symbiosis

Answer 7

it is hypothesized that an archaean cell swallowed aerobic bacteria, consuming the oxygen and releasing some ATP to its host

-eventually becomes the mitochondria in a eukaryotic cell

Question 8

acritarchs

Answer 8

• a group name for fossils of life forms that we can’t assign to a specific living group of single-celled life form
• similar to fossilized eukaryotes

Question 9

origin of multicellular life: colonial hypothesis

Answer 9

• dividing cells do not separate after division

- mutation in cell membranes or walls?

Question 10

Ediacaran Fossils

Answer 10

• late precambrian
• Variety of leaf-like jellyfish/wormy life forms.
• Kinda look like ferns
• Fossils of these organisms occur on every continent but antarctica.

Question 11

the cambrian explosion

Answer 11

• diversification in the animal kingdom
• 570MYA
• all modern body plans established in less than 25 MY

Question 12

co-evolution

Answer 12

selection of favourable mutations in a biotic interaction between different organisms