lec 3- evolution Flashcards
what is the concurrent appearance model?
a place where both membranes and polymers can form together
why are abiogenesis processes highly unlikely?
there are higher levels of radiation and ultraviolet near the surface, hence breaking down macromolecules
where is the synthesis and accumulation of organic molecules more likely to occur on earth?
in deep sea vents where there is less radiation, ideal temperatures and a vast amount of elements near by which are needed to form
what thermal vents are more likely to be the host of life’s origins?
white smokers which have temperatures compatible with life and a variety of elements needed for life
what elements are located in white smokers?
methane, CO2, sulfides, and other important chemicals are present
what is the panspermia hypothesis?
life originated elsewhere in the universe, and was seeded on earth from space as microorganisms from comets, asteroids, etc.
what has been extracted from asteroids like carbonaceous chondrites?
Lipid vesicles and many amino acids and other biomolecules
does mars have flowing water?
yes, could mean that life existed their before
if life existed on the red planet, what life form might be found?
stromatolites (small microbes)
what are the 3 things all life share?
- universal genetic code
- use of ribosomes, DNA, polymerase, and 20 amino acids
- use of ATP for energy storage and conversion
what is the one ancestor of all life?
LUCA (last universal common ancestor)
is LUCA the first life?
no, it is the last common ancestor we know of that survived
where did LUCA most likely live?
in deep sea hydrothermal vents
what was observed about thermophiles?
they appear early in the phylogenies of Archaean and bacteria, indicating a hot source is possible for the origin of LUCA
what main life form dominated the paleozoic?
microbes, have enormous genetic diversity
what is the most probable ancestors of eukaryotes?
Archaean because they aren’t photosynthetic and contain unique proteins for transcribing RNA and DNA, similar to eukaryotes but different in membranes
how did early RNA based life exchange genetic material?
most likely via horizontal gene transfer by absorption from the environment or direct transfer
what dominated the earth before LUCA?
pre life or progenotes
what happened to life after LUCA?
variable descendants formed, setting in motion selection processes that favoured some variation over others, surviving forms moved forward and a process of natural selection continued
What were the first fossil remains of bacteria that was photosynthetic over 3.5 bya?
stromatolites
what are stromatolites?
layered sedimentary structures created by layers of photosynthetic microorganisms like cyanobacteria
what do photosynthetic microorganisms secrete to create stromatolites?
adhesive compounds that form mineral mats
what are the living structures of stromatolites called
microbialites
what is the definition of biological evolution?
any changes in the inherited genetic traits in a population of a species from one generation to the next
do individuals evolve?
no, only populations
can evolution be fast and slow?
yes, slow if vertical transfer, quicker if horizontal
what are the smallest life like organisms?
viruses, though not living,they have few pieces of RNA and are parasitic to organisms
what are some mutations of the flu?
H1N1: the swine flu, mutations in the surface proteins known as hemaglutinin 1 and neuraminidase 1
H5N1: a subtype where mutation occurs in hemaglutinin 5 and neuraminidase 1
how do flu and viruses get past defenses?
by mutations and changes in their surface proteins
what is neuraminidase?
an exit protein
does influenza have rapid microevolution?
yes, rapid rates of new variants and old one die out
what is viral reassortment?
when a virus exchanges surface proteins (genetic material) with one another, allowing new variants to be formed resulting in the virus bypassing the immune system
how many people died to the flu in 1918?
40-50 million
what is the original virus from which COVID-19 turned into its variant?
SARS-CoV-2
