Lecture 18 sex, reproductive systems and evolution

Question 1

What are the two reproductive systems and their definitions?

Answer 1

Asexual(making clones of themselves, violation of Mendel laws) and sexual (separate sexes or hermaphroditic)

Question 2

What are the two sexual systems and their definitions?

Answer 2

Dioecious (male and female organs in separate organisms) and hermaphroditism

Question 3

What are the two mating systems and their definitions?

Answer 3

Cross-fertilization (mating with other organisms and self-fertilization (mating with yourself)

Question 4

What is sexual reproduction?

Answer 4

When two parents contribute genetic material to offspring

Question 5

What does sexual reproduction involve?(2)

Answer 5

Meiotic reduction division to form gametes (a division of a cell to one haploid)
Fusion of gametes (when the sperm and egg meet)

Question 6

What is a asexual reproduction?

Answer 6

Only one parent contributes genetic material To offspring

Question 7

Is meiotic reductive division required in asexual reproduction?

Answer 7

No

Question 8

What are offspring like in asexual reproduction?

Answer 8

Offspring are genetic replicas of parent (look identical to parent)

Question 9

What was Darwin’s view of sex?

Answer 9

We don’t know the cause of sexuality or why two gametes should fuse together, the whole thing is a mystery

Question 10

How do Eukaryotic organism reproduce?

Answer 10

asexually rather than sexually

Question 11

How do eukaryotes reproduce in cooler water?

Answer 11

Asexually

Question 12

How do eukaryotes reproduce in warm water?

Answer 12

Sexually

Question 13

What is the relationship between reproductive systems and the environment?

Answer 13

Different reproductive systems occur in different environments

Question 14

Many perennial plants reproduce through both sexual and asexual reproduction. What are they considered because of this?

Answer 14

An invasive species

Question 15

What are the costs of sex?(5)

Answer 15

Time and energy to find and attract mates (dating cost)

Risk of predation and infection (by going out to finding mate rather than reproducing with yourself)

Cost of producing males

50% less genetic transmission

Break up of adaptive gene combinations; segregation and recombination

Question 16

What are the benefits of sex known as a paradox?

Answer 16

Why it has evolves even though it is cons

Question 17

What is Two fold
cost of meiosis?

Answer 17

Sexual females contribute only 50% of genes to population

Question 18

What is transmission biases?

Answer 18

when one trait is more likely to be copied than the other

Question 19

What does transmission bias favour?

Answer 19

Asexuals in female competition

Question 20

What is the relationship between asexual reproduction and alleles?

Answer 20

Asexuals reproduction maintains favorable combinations of alleles

Question 21

What is the benefit of the AA allele combination?

Answer 21

AA helps adapt to wet environments

Question 22

What is the benefit of the aa allele combination?

Answer 22

aa helps adapt to dry environment

Question 23

What is the benefit of the Aa allele combination?

Answer 23

Aa helps adapt to neither wet or dry environments

Question 24

What is a con of sexual reproduction regarding alleles?

Answer 24

can continuously recreate undesirable combinations of alleles

Question 25

What are Hypotheses for the advantages of sex?(3)

Answer 25

Bringing together favourable mutations Eliminating harmful mutations Aids in genetic Variation

Question 26

What is the tangled bank hypothesis?

Answer 26

sexually reproducing species have an advantage over asexual individuals in the amount of offspring they can produce in a particular environment

Question 27

Which form of reproduction causes favourable variations of mutations to be brought together more rapidly?

Answer 27

During sex

Question 28

What are Asexual Oenothera?

Answer 28

species are diploidand do not need chromosome segregation and recombination during meiosis

Question 29

What do Asexual Oenothera have and what is the con to this?

Answer 29

Have more premature stop codon mutations Leads to dysfunctional proteins

Question 30

What do dysfunctional proteins in Asexual Oenothera imply?

Answer 30

Higher rates of protein sequence evolution Implies greater accumulation of deleterious mutations

Question 31

Why is cloning yourself the best option in a homogeneous environment?

Answer 31

cloning yourself may be the best strategy because lack of diversity suggest selection has built up the optimal genotype

Question 32

Which type of reproduction method do heterogenous environments favour?

Answer 32

Sexual reproduction

Question 33

What is the sex rate in homogeneous environments compared to heterogenous environments?

Answer 33

Sex declines rapidly in homogenous environments Sex rate maintained at a much higher level in heterogeneous environments

Question 34

What is Asexuality by parthenogenesis?

Answer 34

female can produce an embryo without fertilizing an egg with sperm

Question 35

Which types of animals use parthenogenesis?

Answer 35

invertebrates

Question 36

what is Asexuality by clonal propagation?

Answer 36

multiplication of genetically identical copies of individual plants

Question 37

Which types of species go through clonal propagation?

Answer 37

common in plants

Question 38

are many species exclusively asexual?

Answer 38

no

Question 39

where are Asexual species usually located in phylogenies?

Answer 39

at the tip

Question 40

how are Macroevolutionary patterns in asexual species related to extinction risk? why is this

Answer 40

indicates a higher extinction rate why: low genetic variation & accumulation of deleterious mutations

Question 41

what is the Mystery of Bdelloid rotifers?

Answer 41

they can go millions of years without having sex

Question 42

what are mates like in terms of relativeness in outbreeding

Answer 42

less relative than random

Question 43

what are mates like in terms of relativeness in inbreeding?

Answer 43

they are more related than random

Question 44

what is outcrossing?

Answer 44

when an organism breeds with another organism that is not closely related to it

Question 45

can outcrossing be inbreeding or outbreeding?

Answer 45

yes

Question 46

what is Selfing or self-fertilization?

Answer 46

fusion of male and female gametes by the same individual

Question 47

what is the most extreme form of inbreeding

Answer 47

Selfing

Question 48

what causes the Fusion of gametes in outcrossing?

Answer 48

2 parents

Question 49

what is the Fusion of gametes in inbreeding?

Answer 49

Fusion of gametes from 1 parent

Question 50

what are Gametes derive from in outcrossing and inbreeding?

Answer 50

Gametes derive from meiotic reductive division

Question 51

what does Local population substructure enhance?

Answer 51

mating among relatives

Question 52

What is mating like in small populations?

Answer 52

even random mating can lead to mating among relatives

Question 53

what do flowers do to avoid inbreeding in terms of their appearance?

Answer 53

develop large, showy flowers to attract pollinators

Question 54

what do flowers do to avoid inbreeding in terms of their reproduction timing?

Answer 54

Change timing offset between male and female reproduction. specifically, pollen vs ovulation timing and when male and female flowers open

Question 55

what is an example of a physiological mechanisms to avoid selfing?

Answer 55

spacing of anther and stigma

Question 56

what are inbreeding Avoidance Behaviors in Animals? (4)

Answer 56

Dispersal by one sex (one sex moving away from others of the same breed) delayed maturation extra pair copulation (mating with someone else other than your long-term partner) kin recognition and avoidance (an organism's ability to distinguish between close genetic kin and non-kin and avoid genetic kin)

Question 57

how do Population genetic effects relate to genotype in inbreeding?

Answer 57

changes genotype frequency

Question 58

how do Population genetic effects relate to homozygosity in inbreeding?

Answer 58

increases homozygosity

Question 59

how do Population genetic effects relate to heterozygosity in inbreeding?

Answer 59

decreases heterozygosity

Question 60

how do Population genetic effects relate to alleles in inbreeding?

Answer 60

no direct effect on allele frequencies

Question 61

how do Population genetic effects relate to polymorphism in inbreeding?

Answer 61

does not affect polymorphism

Question 62

what is the trends of sefling, sibling and first cousin mating on a graph describing the effect of inbreeding on the rate of heterozygosity decline depending on mating patterns?

Answer 62

selfing is the steepest sibling is the second-steepest double first cousin is the least steep

Question 63

what is Inbreeding Depression?

Answer 63

reduced fitness of inbred offspring compared to outcrossed offspring

Question 64

what are the affect of inbreeding Depression?

Answer 64

lower viability (survival) lower fertility (ability to reproduce)

Question 65

what does Strong inbreeding depression disfavour? what does it favour instead?

Answer 65

inbred offspring thus favoring outcrossed mating systems

Question 66

Why can inbreeding reduce fitness?

Answer 66

Homozygosity of recessive deleterious alleles

Question 67

The genetic consequences of inbreeding in terms of heterozygosity?

Answer 67

Heterozygosity (H) reduced by 50% per generation with self-fertilization

Question 68

The genetic consequences of inbreeding in terms of homozygous genotypes?

Answer 68

Competition between homozygous genotypes

Question 69

The genetic consequences of inbreeding in terms of genetic drift?

Answer 69

genetic drift of small populations can reduce phenotype

Question 70

what does Homozygosity for deleterious recessive alleles result in?

Answer 70

inbreeding depression

Question 71

how many genes do out crossers produce? where do the genes come from?

Answer 71

2 genes in total, one from the seen and one from the pollen

Question 72

how many genes do sellers produce? where do the genes come from?

Answer 72

three genes in total, two from the seed and one from the pollen

Question 73

what condition is needed for selfing to spread and how does it spread?

Answer 73

If conditions are favourable selfing can spread via natural selection

Question 74

what do harmful effects of inbreeding depression encourage?

Answer 74

outbreeding depression

Question 75

why does selfing have a lack of reproductive assurance?

Answer 75

due to rarity of pollinators or mates

Question 76

what does "Transmission advantage from self + exported pollen" mean?

Answer 76

because selfers and outcrosses both transmit copies of genes through pollen but selfers transmit twice as many through seed, selfers have an automatic advantage at the gene level compared to out crossers

Question 77

how does selfing do to diversity?

Answer 77

decreases diversity

Question 78

how does selfing relate to selection?

Answer 78

decreases selection

Question 79

how does selfing relate to extinction?

Answer 79

drive higher extinction rates

Question 80

why is the macroevolutionary pattern of greater prevalence in outcrossing?

Answer 80

encourages phenotypic variability