exam 2 answers

Question 1

compare/contrast biogenesis snad spontaneous generation

Answer 1

biogenesis: theory that living matter originates from pre-existing living matter

spont gen: theory that living amtter can come from non-living matter

dif: they were competing theories until louis pasteur showed that biogenesis was supported in experiments. bio genesis says life can only come from other life while spont gen says life can come from non living things

Question 2

compare/contrast protogenote and protobiont

Answer 2

protogenote: stage between when life originated and presence of the last universal common ancestor of the 3 domains

protobiont: stage in evo of life that concerns confitions and steps that must have happened up to the beginning of a living cell

dif: protobiont was before all life; protogenote was after life originated but before the last universal common ancestor

Question 3

compare/contrast gram neg vs gram pos bacteria

Answer 3

gram neg: thin peptidoglycan between inner and outer cell membranes which does not absorb stain

gram pos: have thicker peptidoglycan layer that absorbs stain

dif: gram neg has thinner peptidoglycan and does not absorb stain. gram pos has thicker peptidoglycan and does absorb stain. this was a way to distinguish bacteria before DNA sequencing

Question 4

compare/contrast holometabolous and hemimetabolous development

Answer 4

holo: juveniles look very different from adults. organisms go through metamorphosis where the organs completely reorganize to form the adult

hemi: juveniles look life adults. development is not entire metamorphosis and the same organs are present through the whole life time

dif: holo is whole metamorphosis and adults look very different from uveniles. hemi is not metamorphosis and juveniles look similar to adults

Question 5

ony hypothesis of animal relationships is shown below. according to this set of relationships, how many times did the nervous system evolve in animalia?

Answer 5

2

Question 6

what 2 kinds of tectonic plates are involved in mtn formation along the western coast of the US

Answer 6

oceanic goes under a continental

Question 7

explain the process that powers tectonic plate mvmt

Answer 7

core of the earth is liquid and the plates are floating on the semi-molten layer; energy from the molten core pushes the plates

Question 8

where do humans acquire their gut microbiome?

Answer 8

from the environment around them

Question 9

how many genomes are in the organisms below and where are they located?

Answer 9

1) in the chloroplast
2) nucleomorph
3) mitochondria
4) nucleus

Question 10

what are two reasons why there are so few fossil organisms from before the cambrian?

Answer 10

1) most orgs were small and soft bodied which don’t fossilze easily.

2) orgs that live in O2 rich enviros decompose quickly; O2 poor enviros favor fossilization. geo processes destroy fossils or bury them. the fossil record is most complete for marine groups with hard skeletons. orgs were small before cambrian.

Question 11

what are 2 arguments suggesting the protocell mem was not a phospholipid bilayer?

Answer 11

phospholipid bilayers are highly organized membranes and it’s hard for organic molecules to cross. transport of materials across a phospholipid bilayer requires protein pumps. This complexity wouldn’t be possible because RNA had to cross the membrane. It’s more likely that the earliest membranes were made of loosely organized fatty acids

Question 12

explain why prokaryotes are paraphyletic

Answer 12

paraphyletic group = includes common ancestor but not all descendants. prokaryotes includes bacteria and archaea. since bacteria were the first branch of life, it’s referring to the common ancestor of bacteria and archaea but not eukaryotes which is one of the descendants.

Question 13

assume that you find a fossil tooth of an extinct horse and are interested in estimating how long ago it roamed the earth. if the half-life of the isotope you measure is 20,000 yrs and you only find 12.5% of the isotope, approx how old is your specimen?

Answer 13

60,000 years

Question 14

what are 4 synapomorphies of all life?

Answer 14

• DNA replication
• CAC
• cell membrane
• universal genetic code

Question 15

discuss 2 lines of evidence that support the recognition of a new geological era called the anthropocene

Answer 15

1) mass extinction bc of humans
2) chemical signature from plastics, nitrogen, and CO2

Question 16

according to the figure below, what’s the sister group of humans and approx how long ago did the divergence event occur?

Answer 16

sister group = common ancestor of common and pygmy chimps; 6-8 mya

Question 17

what are 3 advantages of using the 16s ribosomal subunit to understand the relationships of all life?

Answer 17

1) present in the CA of all life and is evo ancient

2) no free-living organism lacks rRNA so it can be compared across tree of life

3) rRNA is important fro translation so lateral gene transfer is unlikely

4) rRNA evolved slow that gene sequences from distantly related species can be compared