What types of reproduction exist?
Asexual reproduction: one individual
Sexual reproduction: two individuals
What is the advantage of sexual reproduction?
Source of variability
Why are there only two sexes?
Two sexes generate almost endless combinations
Sufficient to guarantee variability
What is sexual behavior?
A:
All behaviors linked to sexual reproduction
High diversity
How is a female defined
Produces few sex cells
Large
Immobile
Ovules / eggs
How is a male defined?
Produces many sex cells
Small
Mobile
Spermatozoids
What is hermaphroditism?
Presence of both sexual functions
Can be simultaneous or serial
What are gonochoric species?
Non-hermaphroditic species
One sex for life
What is protandry?
Sex change from male to female
What is protogyny?
Sex change from female to male
What types of sex determination exist?
Environmental determination
Incubation temperature
Food availability
Chromosomal determination
What is primary sexual dimorphism?
Differences in sexual organs
Gonads
Internal and external genitalia
What is secondary sexual dimorphism?
Morphological traits
Physiological traits
Behavioral traits
Not directly linked to sexual organs
What causes sexual dimorphism?
Sexual selection
What is sexual selection?
Selection of morpho-behavioral traits
Favors reproductive success
What is intrasexual selection?
Competition between individuals of the same sex
What is intersexual selection?
Selection by the opposite sex
Mate choice
What is reproductive effort / parental investment?
Time
Energy
Resources invested in reproduction
How does reproductive effort differ between sexes?
Males: courtship and mating
Females: pre- and post-natal care
What are optimal sexual strategies?
Strategies linked to intrinsic characteristics of males and females
What sexual strategy do males usually follow?
Quantitative strategy
Maximize number of mates
What sexual strategy do females usually follow?
Qualitative strategy
Select the best mate
What is the Coolidge effect?
Renewed sexual interest of males when a new female is introduced
What are the phases of sexual behavior?
Attraction
Courtship
Fertilization
Parental care
Why are females generally more selective?
Sensitivity to traits indicating reproductive success
What characterizes attractive traits?
Visible during courtship
Indicate quality/resources
Easy to perceive
Can attract predators
What is Fisher’s runaway selection hypothesis?A:
Female preference exaggerates male traits
Balance between sexual and natural selection
What are the functions of courtship?
Find a mate
Identify species and sex
Identify physiological disposition
Reduce interindividual distance
Avoid aggression or escape
How does courtship help mate choice?
Evaluation of partner quality
: What is the role of courtship in synchrony?
Reciprocal stimulation
Synchronization of sexual activity
What types of fertilization exist?
External
Indirect internal
Direct internal
What is a mating system?
Pattern of social relationships between males and females
Monogamy
Polygamy
How common is monogamy?
Rare in mammals and invertebrates
Common in birds
What is polygyny?
One male mates with several females
It exists:
Female monopolization (harem / resource defence)
Lek system
What is polyandry?
One female mates with several males
Rare
What is polygynandry?
Multi-male, multi-female mating
Sperm competition
What shows that sex is not always linked to reproduction?
Sex during pregnancy or lactation
Homosexual behavior
Playful sex
What is alloparental care?
Adavantages?
Care provided by individuals other than the parents
Benefits offspring
Benefits the mother
Benefits the allomother
What is play?
Motor activity
No immediate purpose
Altered form and sequence
What are indicators of play?
Exaggeration
Role inversion
Absence of fear or submission
What are the functions of play?
Practice adult behaviors
Learning
What types of play exist?
Locomotor play
Social play
Object play
Fantasy play
Last changed7 days ago