Reproduction
Asexual Reproduction- involves only one
parent, produces a new organism
genetically identical to the parent.
Sexual Reproduction- involves the
production and fusion of sperm and egg (1
or 2 parents), produces variation in
offspring.
Asexual vs Sexual Reproduction
Asexual
# of parents
Gametes
produced?
Genetic Variety?
Time needed to
produce
offspring
Sexual
Asexual Reproduction
Only 1 Parent-All Kingdoms
1. Binary Fission/Mitosis-one cell divides into two cells…
Binary Fission/Mitosis allows for no genetic
variability!
Bacteria- Binary Fission- splitting
into 2
How fast can bacteria reproduce?
Exponential growth
•
•
•
•
•
•
•
•
•
•
1
2
4
8
16
32
64
128
256
512
Single celled Eukaryotes- Mitosis
(nucleus breaks apart and reforms
2 nuclei in 2 different cells)
2. Budding-offspring begins to develop on the
parents body and then fragments off the original parentHydra
Figure 46.1 Two from one: asexual reproduction of a sea anemone (Anthopleura
elegantissima)
3. Vegetative Propagation
producing new plants from
existing vegetative structures,
4. Fragmentation
the body of the parent breaks into distinct pieces,
each of which can produce an offspring
Sea Stars
Sponges
5. Regeneration
if a piece of a parent is detached, it can
regrow
6. Parthenogenesis
An unfertilized egg develops into
an adult
• Parthenogenesis: Aphids, honeybees,
lizards
7. Spore Formation
• Are produced by many organisms(algae,
fungi, bacteria)
• Contain DNA, Cytoplasm & tough outer
wall-protects it from drying out.
When conditions are favorablespores germinate & grow
Sexual Reproduction
Simple Sexual Reproduction
Conjugation: sexual process in
some simple organisms in
which genetic material is
transferred by cell to cell
contact.
1. Kingdom Protist: Algae
ex: Chlamydamonas
• Alternation of generations:
both haploid and diploid
generations exist
asexual
n
Sexual
conjugation
2n
zygospore
Chlamydomonas- (green algae) Reproduces asexually most
of the time, it can also reproduce sexually under certain
environmental conditions.
2. Kingdom Fungi
• Conjugation occurs between different hypha
Bread Mold
3. Kingdom Eubacteria: prokaryotes
• Not a true form of sexual reproduction
• Plasmid: pieces of genetic material transferred
from one bacteria to another
• Form a connecting bridge of cytoplasm (pilus)
Stamens & Carpels
Pollination/Fertilization
Plant life cycles
• 2 Stages- alternation of generations.
• Sporophyte-is the diploid (2n) stage that
produces spores by meiosis
• Gametophyte-is the haploid(n) stage that
produces gametes by mitosis (pollen, ovule)
Sexual Reproduction
• Pollen production
In the female gametophyte-2 haploid
nuclei go to the center-polar nuclei & 1
egg.
• Male Gametophyte is in the pollen on the
anther.
• Female Gametophyte is in the ovule in the
ovary.
Parts of a Flower
Stigma
Petal
Style
Sepal
Filament
Anther
ovary
8. Structures 1, 3, & 7 make up the structured female structure called the
9. Structures 5 & 6 make up the male structure called the
10. The ovule(s) is found within the
11. Which structure is the site of pollen production?
12. Which structure is the recipient of the pollen?
13. Which structure protects the reproductive parts and attracts pollinators?
14. The structure that will eventually become a fruit is the
15. The structure that holds the anther upright is the
16. Does a plant produce more pollen or more ovules? Explain.
Double Fertilization
Double Fertilization-1 sperm fertilizes the
central cell (future endosperm), other
fertilizes the egg (future embryo)
• Double fertilization
Sexual Reproduction
• Female Gametophyte
What is
3n? 2n?
What part
will become
food for the
new
embryo?
Sexual Reproduction
Reproduction in Animals
• For almost all animals, the organism is
always diploid
• Only the gametes are haploid
Some animals may be able to reproduce
either asexually or sexually, like the
sponges. More complex animals, it is
sexual reproduction that is predominant.
Gametes are produced in the sex organs –
gonads
Sperm is produced in the testes
Eggs are produced in the ovaries.
Gametes are made through the process of
meiosis
Among simpler organisms, both kinds of sex
organs develop in the same individual.
These animals are called hermaphrodites
Why would separate sexes be an
adaptation?
MORE VARIETY
Fertilization
Sperm + Egg
There are 2 types of fertilization
• Internal Fertilization-
• External Fertilization-
Figure 46.0 Frogs mating
Figure 46.4 The release of eggs and external fertilization
Sexual Reproduction
• External fertilization
– Large numbers of gametes
– Synchronized release of gametes
– Mating behaviors
Do animals that
use external
fertilization exhibit
parental care?
External Fertilization
• External: - little or no care for young,
many offspring, external fertilization and
external development, young dispersed
widely, can repopulate a niche quickly
Spawning
External fertilization
Video clip from s drive
Sexual Reproduction
• Internal fertilization
– Many male, few female gametes
– Mating behaviors (courtship, estrous cycles)
– Parental care
– Few offspring
Internal Fertilization
• Internal care for young, generally few
offspring at once, internal fertilization shelled eggs or live birth.
Figure 46.0x1 Utethesia ornatrix mating
Figure 46.0x2 Red beetles mating
Figure 46.x1 Aphid giving live birth
Figure 46.3 Sex reversal in a sequential hermaphrodite
External vs. Internal Fertilization
Figure 46.12 Structure of a human sperm cell
Figure 46.8 Reproductive anatomy of the human male
Figure 46.8 Reproductive anatomy of the human male (continued)
Sexual Reproduction
• Male Reproductive Structures
What is the
function of each?
Identify:
Bladder
Penis
Urethra
Testes
Epididymus
Vas deferens
Seminal vesicle
Bulbourethral
gland
Prostate
Rectum
Scrotum
Seminiferous
tubules
Male Secondary Sex
Characteristics
•
•
•
•
Increased Musculature
Deeper Voice (Larynx)
Pubic Hair
Spermatogenesis
Spermatogenesis
• Everyday millions of
Stem cells in the
Seminiferous tubules
Undergo meiosis.
Figure 46.9 Reproductive anatomy of the human female
Figure 46.9 Reproductive anatomy of the human female (continued)
Sexual Reproduction
• Female Reproductive Structures
What is the function of
each structure?
Identify:
Bladder
Oviduct
Ovary
Uterus
Cervix
Vagina
Pubic
bone
Urethra
Rectum
Sexual Reproduction
• Another look
Please label.
Where does
fertilization take
place?
Implantation?
Where does the
fetus develop?
Figure 46.13b Oogenesis
Figure 46.16 Formation of the zygote and early postfertilization events
Estrogen production
• During puberty the pituatary gland
produces FSH .
• Stimulates the follicle cells to produce
Estrogen.
Estrogen controls Female
Secondary Sex Characteristics
•
•
•
•
Adipose deposits (Breasts)
Widen Pelvic girdle
Pubic hair
Onset of the Menstrual cycle
Menstrual Cycle-4 phases
• Menstruation: Day 1-5-uterine lining is
shed because no pregnancy.
• Follicle phase: Day 6-13-Estrogen levels
rise & stimulate 1 ovum to mature.
• Ovulation: Day 14-hormone levels peak &
the ovum is released from the ovary.
• Luteal Phase-Day 15-28 Follicle cells
become corpus luteum-produce
progesterone-builds up endometrium.
Figure 46.15 The reproductive cycle of the human female
Spawning in Fish
Fertilization-The first sperm to reach the ovum uses
the acrosome to penetrate the membrane and then forms a
fertilization membrane so no other can penetrate.
Implantation Phase
Cleavage Begins
Somites, Leg & Arm buds
Amnion & Yolk Sac
Fetal Membranes
Human Fetus
Fetus sucking thumb
Vernix caseosa & lanugo
24 Weeks
3 Stages of Delivery
Hormonal control of labor