Mitosis and Meiosis Flashcards
Fission
An animal produces a “copy” of
itself without embryonic development
Parthenogenesis
An unfertilized egg develops into an embryo
Sexual reproduction
Male and female gametes form an embryo
Fission
An animal clones of itself without embryonic development
What are advantages of fission
Avoid costs associated with both finding a mate and mating itself
= Risks of predation, aggression from conspecifics, energy costs
Disadvantages of fission
Lack of genetic diversity puts the whole population at risk w/natural selection
Advantages of Parthenogenesis
-Avoid costs associated with finding a compatible mate: search costs in low density of another sex
-Could introduce new chromosome structure with homologous recomb.
-Some forms can introduce the opposite sex within the population (WZ)
Disadvantages of Parthenogenesis
Still does not increase diversity from parent
What are gametes
female eggs (ova) and male sperm
All cells have a pair of each what
Chromosome type (one from each parent), except for gametes which have one of each chromosome type
Advantages of sexual reproduction
-Genetic diversity allows beneficial mutations to
come together in the same individual, enhancing adaptation
-Genetic diversity reduces occurrences of harmful mutations and increases occurrences of resistance to pathogens and parasites
Disadvantages of sexual reproduction
Costs associated with finding a mate and mating:
risks of predation, aggression from conspecifics,
energy costs
Mitosis undergoes 1 round of separation to generate 2 diploid (2N) daughter cells, in what organisms does this take place and what type of cells
in multicellular organisms = somatic cells
How many rounds of separation does meiosis undergo and what does it generate
2 rounds of separation, generates 4 haploid cells called gametes
In meiosis I, homologous chromosomes align, recombine, and separate from each other, how is this different than mitosis?
All chromosomes align independently in mitosis
In meiosis II, sister chromatids are then separated from each other, how is this different than mitosis
Mitosis is 1N
The physical structure of homologous chromosomes being linked by cohesins =
the synaptonemal complex
Chiasma can form along any region of homology, what is this called?
Homologous recombination
Each chiasma represents what
Individual crossovers
Recombination may occur multiple times between two homologs, usually how many times?
2-3 times per pair
What does mendels law of segregation say?
Each parental gamete
contributes 1 and only 1 allele for
a particular gene to its offspring
During gamete formation, what do maternal and paternal alleles do?
Seperate from one another
What does mendels law of independent assortment say
During gamete formation, alleles for different traits segregate independently of one another (they’re on different homologous chromosomes)
Does meiosis support mendels law of idependent assortment?
Meiosis supports this “law” because maternal and paternal chromosomes are not inherited together
