Bio Mid

Front 1

Fill in and order from current to past the major the eras to remember for Bio 155.P_____ , C_____, M_____

Back 1

Current: Cenozoic, Middle: Mesozoic, Past: Paleozoic

Front 2

What happened ~2.5 BYA that significantly affected life today

Back 2

~2.5 BYA the first photosynthetic organisms appeared, beginning a change from a CO2 laden atmosphere towards an O2 atmosphere. This change probably killed off most anaerobic life and allowed aerobic life that we know today to begin.

Front 3

What is a stromatolite?

Back 3

A stromatolite is a fossilized prokaryote community bound in very thin layers of sediment together into rocks

Front 4

All of the following is evidence that mitochondria evolved from bacterial symbionts except: a) Double membranes

b) replicate by fission

c) DNA in chromosomal pairs

d) 1-10 microns in size

e) Have ribosomes

Back 4

DNA in chromosomal pairs

Front 5

__________ and ___________ must occur for evolution to take place.

Back 5

Replication; Mutation

Front 6

What came first? Choose between A/B in each row.

A B

anaerobic prokaryotes photosynthetic prokaryotes

aerobic prokaryotes amino acids

liquid water atmospheric O2

Cambrian Explosion Cenozoic era

Back 6

1-4: A, B, A, A

Front 7

Explain how the first photosynthesizing prokaryotes created selection pressures that dramatically influenced Earth's evolutionary history.

Back 7

The first photosynthesizing prokaryotes were most likely similar to cyanobacteria. These prokaryotes developed the ability to utilize the sun's energy and the atmosphere rich in CO2 to create their own food. The result of this metabolic process was the release of oxygen into the environment. Initially the oxygen remained dissolved in the surrounding aquatic environment inhabited by these organism's; however, eventually the water became saturated and oxygen was released into the atmosphere. This significantly changed the atmosphere to which other organisms had adapted. Oxygen is highly reactive and capable of damaging cells, hence, a selection pressure was created that selected for organisms that were able to tolerate and/or utilize the new atmospheric conditions while other organisms were selected against. This gave rise to the development of oxygen dependent organisms.

Front 8

Briefly explain the two cellular structures that are the basis for the endosymbiotic theory.

Back 8

Eukaryotic organelles such as the mitochrondria and chloroplast are explained by the endosymbiotic theory to have evolved from prokaryotic cells. The theory explains how eukaryotes formed through the symbiosis of prokaryotic cells. Photosynthetic bacteria gave rise to the first photosynthetic eukaryotes, algae, which allowed aerobic eukaryotes to evolve. Chloroplast allow plants to produce oxygen through the uptake of organic molecules and the mitochondria converts sugar and oxygen into usable energy (ATP) for organisms.

Front 9

Which organism is the first evidence of life in the fossil record?

Back 9

Stromatolites

Front 10

Describe the evolution of photosynthesis that transformed the planet.

Back 10

Photosynthesis takes carbon dioxide and produces oxygen. There was very little oxygen in the early atmosphere, but the increasing levels of oxygen from photosynthetic organisms created an environment that some species could not survive in. This eventually led to the rise of oxygen-reliant species.

Front 11

2.7 billion years ago

Back 11

Photosynthetic organisms evolved

Front 12

2.1 billion years ago

Back 12

First eukaryotes evolved

Front 13

3.5 billion years ago

Back 13

First prokaryotes evolved

Front 14

end

Back 14

end