L18 Evolution of Eukaryotes Flashcards
From the earliest fossils, life is estimated to be around…
3.75 BY old
The evidence for the fire life comes from stromatolites, formed by…
Bacteria
It’s estimated that eukaryotes emerged between…
1.2 to 1.6 BYA
The first animal fossils are around…
750 MY old
Was used in the past to build evolutionary trees:
a) Protein sequences
b) DNA and RNA sequences
c) Morphology
d) Physiology
c) Morphology
Main limitations of using morphology for determining ancestors are… (3)
- Lack of fossil records
- Lack of complex morphology in some species
- Not useful for microorganisms
SSU rRNA is more suitable for determining ancestral relationships as…
Changes occur more rapidly than in DNA
The rooted universal SSU rRNA tree shows 3 domains of life…
- Bacteria
- Archaea
- Eucarya
The universal tree shows a common ancestor between arches and eukaryotes, which explains their…
Similarities
Changes to the functional core of SSU rRNA are:
a) not conserved between generations
b) strongly selected against
c) strongly selected for
d) conserved only along the maternal line
b) strongly selected against
As this is the key to the ribosomes function, so changes are likely to disrupt this vital function and so not be passed on
Molecular environmental surveys have allowed scientists to sequence…
Bacterial genomes directly from the environment/ micro biomes
Eukarya have been shown to originate
a) directly from LUCA
b) as a branch of bacteria
C) as a branch of archaea
C) As a branch of archaea
See Asgard Archaea
Last common ancestor of eukaryotes already possessed a complex cell. Was this unique to eukarya?
No, Asgard Archaea were found to closely mirror complex eukaryotic genes
Different genes have different…
Evolutionary histories
Mitochondria are:
a) endosymbionts closely related to agrobacterium
b) endosymbionts with no known relatives
c) descended from ancestral viruses
d) endosymbionts closely related to bangiomorpha
a)
