Lecture 6

Question 1

Parthenogenesis

Answer 1

Asexual reproduction
- embryo develops from the egg w/o fertilization of sperm

Question 2

Clonal propagation

Answer 2

Asexual reproduction
- offspring is created from a piece of the mother
- budding in plants
- cutting a stem and re planting it
- makes identical clones

Question 3

What are the 2 types of sexual systems

Answer 3

1. Dioecious
2. Hermaphrodite

Question 4

Explain dioecious

Answer 4

type of sexual system
either male or female and they only produce 1 type of gametes
male = sperm
female = egg

Question 5

Explain hermaphrodite

Answer 5

type of sexual system
produces both male and female gametes
- common in plants
- can either self-fertilize or cross fertilize

Question 6

Sexual reproduction

Answer 6

2 parents
meiosis
fusion of gametes

Question 6

Cross fertilization

Answer 6

combines gametes with another plant
- flowering plant = egg
- bees = pollen to fertilize
- not clones

Question 7

Self-fertilization

Answer 7

produces ovule and pollen
- reproducing with themselves
- offspring is not a clone (undergo meiosis, independent assortment)

Question 8

asexual reproduction

Answer 8

1 parent
no meiosis
clones

Question 9

T/F
some species have the ability to reproduce SS or AS

Answer 9

True
Water fleas
depending on the environment

Question 10

What are the costs to sex

Answer 10

1. Two-Fold Cost
   - a female only contributes 50% of its genes to the next generation
   - giving away opportunity for the offspring to increase fitness
2. can continuously re-create unfavorable combinations of alleles
3. time and energy to find mates
4. risk of predation and infection while seeking mates or mating
5. costs of producing males - if AS successful then why do we need males

Question 11

What are the benefits of sex

Answer 11

1. Favorable combinations of mutations brought together more rapidly by sex
   - the fit combination spreads quicker
2. Bringing together favorable mutations and eliminations of harmful mutations
   - when crossing 2 heteros, it gives 4 different combinations - some can get rid of the mutations
3. Hypotheses for the advantages of sex
   - lottery models (some combinations can be fit for the environment)
   - what’s fit in one generation may not be fit for another gen

Question 12

T/F
it is harder to get rid of bad mutations in sexual reproductive organisms

Answer 12

FALSE
in AS organisms, it is harder to get rid of because they keep cloning

Question 13

T/F
the long term consequence of AS reproduction is too much mutations = extinction

Answer 13

true

Question 14

Outbreeding

Answer 14

mates less closely related than random
- random species mating

Question 15

Inbreeding

Answer 15

mates are relatives and are not random species
- sometimes species have no choice by to mate with relatives

Question 16

Selfing and asexual reproduction are the same thing

Answer 16

self-fertilization and AS reproduction are not the same
- AS = clones
- Selfing = meiosis

Question 17

How do species prevent inbreeding

Answer 17

plants: timing of male and females are different
- self-incompatibility
- parents stop reproducing after offspring
- makes disperse after mating
- increases homozygosity
- decreases heterozygosity

Question 18

Inbreeding depression

Answer 18

the reduction in fitness of inbred offspring compared to the offspring that are outcrossed
- lower survival
- lower fertility
- strong inbreeding depression = unfavour

Question 19

T/F
Inbreeding depression can change allele frequencies

Answer 19

TRUE
- increase homozygosity and less heterozygosity

Question 20

Selfing

Answer 20

if conditions are favourable selfing can spread via NS
- less dependent on pollinators or mates
LONG TERM: leads to low diversity and inefficient selection
- can drive higher extinction rates