Natural Selection and Early life

Question 1

Natural Selection

Answer 1

Individuals in a population differ in traits
some traits confer an advantage
individuals with better traits survive and reproduce

Question 2

Gene

Answer 2

self-replicating DNA unit that occupies specific location on a chromosome and determines a particular characteristic in an organism

Question 3

Allele

Answer 3

variant form of a given gene that codes for a trait

Question 4

Definition of evolution

Answer 4

change in allele frequencies in a population over time
driven by fitness (reproductive success)

Question 5

Phenotype

Answer 5

interaction between genotype and environment
plasticity (environmentally determined, non-heritable)

Question 6

Binary fission

Answer 6

asexual reproduction in prokaryotes, creates new prokaryotes, and some genetic diversity via mutation
but usually identical

there are other ways of prokaryotes transmitting genetic information but they are not reproduction = other ways of evolution (picking up other genetic material)

Question 7

Asexual reproduction in a single-cell Eukaryote

Answer 7

mitosis and fission
two identical haploid cells

Question 8

Sexual reproduction

Answer 8

Meiosis through reassortment (more possible combinations in gametes) and recombination
source of genetic variation

Question 9

Consequences of sexual reproduction

Answer 9

mate searching costs
competition
display costs (looking cool)

Question 10

what conditions favor sexual reproduction?

Answer 10

good if variable climate
high genes per trait, faster to adapt
low background mortality (high population density)
strong soft selection (who dies depends on fitness of other individuals)
low mutation rate
periodic catastrophes

Question 11

how did eukaryotes arise?

Answer 11

diversified prokaryotic life
oxygenated world
high complexity
different reproductive approach
symbiosis (one archaeon and one or several bacteria like mitochondria)

Question 12

endosymbiosis

Answer 12

one cell engulfs another such that the engulfed cell survives and both cells benefit