1. REPRODUCTION

2. Objectives
Compare asexual and sexual reproduction and discuss advantages and disadvantages of each
Describe the different mechanisms of asexual reproduction (e.g. fission, budding, gemmules, fragmentation)
Relate the choice of reproductive strategy with the availability of mates and resources, environment, and the lifestyle of the organism
Compare internal and external fertilization and discuss advantages and disadvantages of each
Enumerate the parts and describe the functions of the male and female reproductive systems
Describe the events that occur during human sexual response
Describe the structure of the sperm cell and that of the egg cell
Describe the events that occur during fertilization

3. Asexual Reproduction genes come solely from parent
mitotic cell division
most suitable for favorable and stable environments
fission (bacteria, archaea)
gemmule formation (sponges)
budding (yeast, hydra)
regeneration and fragmentation (planarians, echinoderms)
parthenogenesis (some insects, reptiles, fish)*

4. All-female whiptail lizard species
Cnemidophorus mexicanus

5. Sexual Reproduction fusion of haploid gametes to form a diploid zygote
formation of haploid gametes involves meiosis
fertilization restores diploid number
used during times of great stress
increases genetic variety through gene shuffling

6. External and Internal Fertilization
external - egg is fertilized in the environment
more zygotes are produced
often triggered by chemical/behavioral factors (e.g. pheromones)‏
internal - egg is fertilized in the female reproductive tract
less zygotes
parental care increases chances for survival

7. Different Reproductive Strategies
Reproductive cycles (mammals)
periodic, controlled by hormones
Alternatingly asexual/sexual (aphids, rotifers)
depends on environmental conditions
Hermaphroditism (tapeworms)
each individual has both male and female reproductive organs
Sequential hermaphroditism (wrasses)
conversion between sexes (protogynous, protandrous)
Parthenogenesis (some insects, reptiles, fish)

8. Mammalian reproductive systems (male)
External
scrotum
penis
Internal
gonads - produce gametes and hormones
accessory glands - secrete products essential to sperm movement
ducts - carry sperm and glandular secretions

9. 4) Produce a fructose-rich fluid that aids in sperm motility
5) Produce an alkaline-rich fluid that prolongs sperm lifespans
7) Common passageway of sperm and urine
6) Produce a clear mucus that neutralizes acidic urine
2) Tightly-coiled tubes that make sperm motile and potent
3) Muscular tube that transports sperm from testes to urethra
1) Seminiferous tubules (sperm) and Leydig cells (testosterone)

10. Mammalian reproductive systems (female)
External
clitoris
two sets of labia
Bartholin’s glands
Internal
pair of gonads
system of ducts and chambers

12. Human Sexual Response Phases of HSR Vasocongestion
Two physiological reactions
Vasocongestion
Filling of a tissue with blood
erection
Flushing, swelling of nipples
Myotonia
Increased muscle tension in smooth and skeletal muscles
Sustained/rhythmic contractions
Phases of HSR
Excitement – prepares vagina/penis for intercourse
Plateau – breathing and heart rate increase
Orgasm – rhythmic, involuntary contractions
Resolution – reverses response of previous phases

13. Human Sexual Response

14. Structure of the sperm cell
Head
Acrosome
helps penetrate the egg cell with its enzymes
Nucleus
Centriole
Middle piece/body
contains large amounts of mitochondria that provide ATP for movement of the tail
Tail

16. Structure of the egg cell
Corona radiata
covering that supplies vital
proteins to the cell
Zona pellucida
binds spermatozoa
required to initiate the acrosome reaction
used for protection
very essential for the oocyte’s death and fertilization
Nucleolus
non-membrane bound structure made of protein and nucleic acid and transcribes RNA

19. Fertilization Capacitation Separation of follicle cells
Sperm-zona pellucida binding
Acrosomal reaction
Sperm-oocyte binding
Egg activation and the cortical reaction
Fast block to polyspermy
Slow block to polyspermy