polygynae, polyandry, handicap theory, runaway theory

1. SEXUAL
SELECTION

2. Mating behaviour and reproductive success
Difference between sexual selection and natural selection
Why Sexual Selection Is Important
Different Between Polygamous And Monogamous Condition
Polygamous Polygynae Polyandry
Why Polygyny Is More Common In Nature
Cast And Choice Of Female For Male
Female Priority During Mating Behaviour
Handicap Theory Runway Theory
Key point

3. Why mating success is important?
Sex Has 50% Cost
Reproduction Cost Is Very High
Life Uses Sexual Reproduction Because It Mutation Because It Maintain
Variation And Better Reproductive Fitness To Maintain Biodiversity
Sex Can Accelerate The Rate Of Evolution

4. Asexual reproduction Sexual reproduction
Natural selection Sexual selection
• It is selection for adaptation
• It Manny stressful upon survival
• Eventual reproduction
• it increase mating success of individual
• sexual selection increase reproductive fitness
• Indirectly favour for variation and evolution
100%
Offspring
Increase homozygous nature
No new character evolve
100%
character
50%
50%
Offspring
Variation increases
New character evolve

5. • Variation occur at each generation
• Sexual reproduction can enable female to reduce the number of
deleterious mutation in their offspring
• Mutational theory predict
Advantages Of Sexual Reproduction

6. Sexual
reproduction
Polygamous Monogamous
Polygynae Polyandry
Poly means many
and gamous mean mating partner
when one female mate with many males,
or one male mate with many female
One male and one female
participate in mating
no more difference in male and female

7. Polygynae
Many female
Single male select for
mating
select
E.g. of polygynae
• Red deer
• Elephant seal
• Spotted hyena
• Gorilla
• Bengal tiger
Condition
• Cost high for female because more energy invest in offspring production and parental care. So select
better male number
• Choice female have more choice
• Pressure Male have more pressure for selection in reproduction
• sexual dimorphism develops between male and female
• Intrasexual competition developed male for selection
better genes better protein better phenotype better physical appearance attractive
increase reproductive fitness more healthy offspring better adaptation
1 2 3 4
5 6
Poly means many gynae means gynoecium i.e. female
When many female mate with male

8. Polyandry
Andry means androecium i.e. many male mate with one female
Less common in nature because of most of time energy investment is more done by
female
polyandry condition exist
Cost- high for male
Choice - male have choice option
Pressure - more pressure on female for selection in reproduction
Many male
Select
One female

9. • Male or more in number that gives choice to female
• Male or more attractive than female
• Male are possessive for female
• Sexual selection operates only one sex of the species
• Example peacock
important character of polygyny condition
intrasexual competition among the members of male develop competition for female mate
selection during this competition female Peacock increase their tail very long and colourful for more
attraction to female
male are more attractive colourful feather and long tail
Female are less attractive
Run away theory the evolution of longer tail in male and mating performance of female continuous
in force to each other that is male and female in runaway process development and better mate selection

10. Handicap theory During runaway theory, continues increase the length of tail in male Peacock for
selection in reproduction create more weight of male Peacock and due to which male Peacock cannot
flight more distance and become more prone to predator. that is overweight due to longer tail make
handicapped male Peacock to their predator and survival of male Peacock
that is sexual selection increase reproductive fitness but make more prone to extinction male Peacock
male are more in number
Female select those Male which are attractive healthy and better gene containing for better and healthy
offspring and to avoid deleterious Mutation or abnormal character those Male which are more care taker,
parental care, territory, best gene.
Male are possessive for female and do intersexual competition
Female priority during male selection in polygyny condition