unit 2 reproduksi tumbuhan dan hewan
FOTO
YANG
RELEVAN
Latar Belakang
gai berikut :
• Pada K-13 terdapat KD sebagai
3.2 Memahami reproduksi pada tumbuhan
tum
dan hewan, sifat
keturunan, serta kelangsungan
an makhluk hidup
4.2 Menyajikan karya hasil perkemb
embangbiakan pada tumbuhan
• Kemampuan apa saja yang haru
arus dilatihkan ke siswa?
• Materi apa saja yang harus dipe
ipelajari siswa?
• Bagaimana kegiatan belajar yang sesuai dengan kemampuan
dan materi tersebut?
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Application
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3.2 Memahami reproduksi pada
da tumbuhan dan hewan, sifat
keturunan, serta kelangsungan makhluk
m
hidup
4.2 Menyajikan karya hasil perke
kembangbiakan pada tumbuhan
2
3
*
KD 3.3
KD 4.3
Berbagi Gagasan
•Sajikanlah hasil diskusi kelom
kelompok Saudara
kepada kelompok lain
•Kelompok lain: Berikan komentar,
kom
khususnya
terkait KETEPATAN jawaban
an aatas pertanyaan
tadi.
SISTEM REPRODUK
DUKSI TUMBUHAN
• Vegetatif (asexual)
Lebih sering terjadi
pada Tumbuhan.
Tidak melibatkan
pertemuan gamet
jantan dan gamet
betina.
• Generatif (sexual)
Terjadi baik pada
Tumbuhan maupun
Hewan
Melibatkan pertemuan
gamet jantan dan
betina.
BEBERAPA CONTOH REPRODUK
DUKSI SECARA VEGETATIF ALAMI
DAN BUATAN PAD
PADA TUMBUHAN
•
Alami
1. Tunas (pisang, tebuh, pohon
pinang dan bambu).
2. Spora (Lumut dan tumbuhan
paku)
3. Tunas adventif (cocor bebek)
4. Stolon / geragih (pegagan,
strawberry, semanggi)
5. Rizoma / rimpang (Kunyit, jahe,
Bangle, lengkuas dan tebuh.
6. Umbi batang (kentang, ubi jalar)
7. Umbi lapis (bawang-bawangan
dan bunga tulip).
• Buatan
Mencangkok
Menempel/Okulasi
Menyambung atau Enten
Merunduk
Stek
Kultur jaringan
Asexual Reproduction
Repr
• Asexual reproduction
tion is natural “cloning.”
Parts of the plant, suc
such as leaves or stems,
produce roots and become
bec
an independent
plant.
Sexual Repr
eproduction
• Sexual reproduction
on re
requires fusion of male
cells in the pollen grai
grain with female cells in
the ovule.
Pergiliran
n Ke
Keturunan
• Plants have a double
ble llife cycle with two
distinct forms:
– Sporophyte: produce
ce diploid
d
spores by mitosis.
– Gametophyte: produce
uce gametes by meiosis
Reproduksii Generatif
Gen
pada
Tumbu
mbuhan
Flower
er Parts
P
Klasifikasi
ikasi Bunga
• Bunga lengkap dan bunga
bun tak lengkap
• Bunga sempurna dan
n Bu
Bunga tidak sempurna
MACAM MACAM
AM PENYERBUKAN
BERDASARKAN ASAL
ASA SERBUK SARI
•
•
•
•
Penyerbukan sendiri (aut
autogami)
Penyerbukan tetangga(ge
geitonogami)
Penyerbukan silang(allog
llogami / xenogami)
Penyerbukan bastar (hyb
hybridogami)
MACAM MACAM
AM PENYERBUKAN
BERDASARKAN VEKTOR/PERANTARA.
VEKT
Anemogami (perantaraan
raan angin).
Hidrogami (perantaraan
aan air).
Antropogami (perantaraa
taraan manusia).
Zoidiogami (perantaraan
raan hewan).
siput
serangga
kelelawar
burung
: malakogami
mi
: entomogami
ami
: kiropterogam
gami
: ornitogami
Perkembangan Gener
neratif pada Tumbuhan
•
•
•
•
Konjugasi, yaitu reproduksi generatif
ratif pada tumbuhan yang belum jelas alat
kelaminnya. Contoh: Spyrogyra (ganggang
(gan
hijau) yang koloninya berbentuk
benang.
amet atau kelamin yang sama besar.
Isogami, yaitu peleburan 2 sel game
Contoh:Clamydomonas (ganggang
ng biru)
b
Anisogami, yaitu peleburan 2 sell gamet
gam yang besarnya tidak sama. Gamet
1 lebih kecil (mikrogamet) dan game
amet 2 lebih besar (makrogamet). Contoh:
Ulva (ganggang yang berbentuk lem
lembaran).
Penyerbukan yang diikuti dengan
n pembuahan.
pe
Terjadi pada tumbuhan
berbunga (Antophyta) atau tumbuha
buhan berbiji (Spermatophyta). Alat
kelamin jantan berupa benang sari
ari dan
d alat kelamin betinanya berupa
putik.
MACAM – MACAM
CAM PEMBUAHAN
• GYMNOSPERMAE
terjadi pembuahan
tunggal ( hanya
terbentuk biji)
• ANGIOSPERMAE
terjadi pembuahan
ganda ( terbentuk biji
dan buah)
Angiosperm
erm Life Cycle
Gametogenes
genesis: Male
Gametogenes
enesis: Female
Doublee Fertilization
Fert
LIFE CYCLE
LE O
OF PINUS
STROBI
OBILUS
• Strobilus yang telah
pecah.
• Strobilus yang belum
pecah
TUGAS KELOMPOK
KEL
• Tiap kelompok
Flower
er to Fruit
Ovule
le to Seed
Seed Ana
Anatomy
Seed Germ
ermination
• Umbi bawang merah meng
engandung senyawa
turunan asam amino yang
ang mengandung sulfur yaitu
Sikloalliin 2%, propilalliin
liin dan
d propenilalliin. Bila selsel umbi pecah senyawaa tersebut
te
akan berubah
menjadi bentuk ester ( ester
est asam tiosulfinat),
sulfinil disulfida (Kepaen),
en), disulfida dan polisulfida,
begitu juga tiofen. Di samp
amping itu terbentuk pula
propantial-S-oksida (suatu
atu senyawa yang dapat
menyebabkan keluarnya
ya aair mata).
Disamping turunan asam
am amino,
a
ditemukan pula
adenosine dan prostagland
landin.8,11)
• www.wou.edu
• Buku solomon
Animal Reprodu
oductive Process
Reproduct
duction
• Reproduction is one off the ubiquitous properties of
life.
• Evolution is inextricably
ly linked
lin
to reproduction.
• Two modes of reproductio
ction are recognized:
– Asexual
– Sexual
Asexual vs. Sexua
xual Reproduction
• Asexual reproduction – the production of
offspring whose genes
es aall come from one
parent without the fusio
fusion of egg and sperm.
– Usually diploid eggs are produced by mitosis
which then develop dire
directly.
Asexual vs. Sexual
ual R
Reproduction
• Sexual reproduction – the
production of offspring by
the fusion of haploid
gametes (eggs & sperm)
from two parents to form
a diploid zygote (fertilized
egg).
– Gametes arise by meiosis.
– Genetic variability is
increased by the random
combinations of genes from
the parents.
Asexual Repro
eproduction
• Bacteria and many
protozoa can
reproduce by
binary fission –
separating into two
or more individuals
approximately the
same size.
Asexual Repro
eproduction
• Budding is a form of
asexual reproduction
where new individuals
form as offshoots of a
parent.
• The offspring may
separate or remain
attached to form
colonies.
Asexual Reproduction
Repr
• Freshwater sponges rele
release specialized
groups of cells called gemmules
ge
that can
grow into new individua
iduals.
Asexual Reproduction
Repr
• Fragmentation results
ults w
when an organism’s
body is broken into sev
several pieces and each
piece grows into a new organism.
– Regeneration – the regr
regrowth of lost body parts.
Asexual Repro
eproduction
• Fragmentation occurs
in some sponges,
cnidarians, polychaete
annelids, tunicates.
– Sea stars can
regenerate lost limbs,
but only species in the
genus Linckia can form
new individuals from
broken arms.
Asexual Reproduction
ction - Advantages
• Animals living far from memb
mbers
of their own species can
reproduce without having to
search for a mate.
• Numerous offspring quickly –
ideal for colonizing a new area
area.
• Advantageous in a stable,
favorable environment because
cause
it reproduces a successful
genotype precisely.
Sexual Repr
eproduction
• Generally involves two parents.
pare
• Special germ cells unite to fform a zygote.
• Sexual reproduction recom
combines parental characters.
– A richer, more diversified
d population
po
results.
• In haploid asexual organism
nisms mutations are
expressed and selected quickly.
qui
• In sexual reproduction a normal
no
gene on the
homologous chromosome
me m
may mask a gene
mutation.
Sexual Repr
eproduction
• Why do so many animals
ls re
reproduce sexually rather
than asexually?
• The costs of sexual reprodu
roduction are greater than
asexual methods:
–
–
–
–
More complicated.
Requires more time.
Uses more energy.
The cost of meiosis to thee female
fe
is passage of only half of
her genes to offspring.
uces resources for females that
– Production of males reduce
could produce eggs.
Sexual Repr
eproduction
• However:
ce more
m
novel genotypes to
– Sexual organisms produce
survive in times of environm
onmental change.
– In crowded habitats, selectio
ection is intense and diversity
prevents extinction.
– On a geological time scale
le sexual
se
lineages with less
variation are prone to extinc
xtinction.
– Many invertebrates with both
bo sexual and asexual modes
enjoy the advantages of both.
bot
Parthenog
enogenesis
• Parthenogenesis involv
volves the development of
an embryo from an unfe
unfertilized egg or one
where sperm & egg nuclei
nuc did not fuse.
– Ameiotic parthenogene
enesis – no meiosis, egg is
formed by mitosis (diplo
iploid)
– Meiotic parthenogenesi
nesis – haploid ovum formed
by meiosis, it may be activated
act
by a male (or not).
Parthenog
enogenesis
• In some animals (aphids
hids (kutu daun), rotifers,
Daphnia (crustacea air ttawar)) the females
can produce two types
pes of
o eggs depends on
environment condition.
ion.
– One must be fertilized.
– One type will develop direct
irectly into haploid adults –
parthenogenesis.
duce eggs by mitosis.(hewan
• Haploid females produce
dewasa yang dihasilkan
an bersifat
b
haploid) dan sel-selnya
tidak mengalami miosis
sis dalam
d
pembentukan telur
baru.
Parthenog
enogenesis
• Daphnia reproduce asexually
lly (parthenogenesis)
(p
when
conditions are favorable.
antung musim, reproduksi
• pergantian reproduksi tergantu
aseksual terjadi pada kondisi
isi yang
ya menguntungkan dan
reproduksi seksual terjadi ketik
etika adanya cekaman lingkungan.
• In times of environmental stress,
tress, they utilize sexual
reproduction.
– Increases variation!
Parthenog
enogenesis
• In many social insects,
ts, like
l honeybees, males
(drones) (lebah madu
du ja
jantan) are haploid and
are produced by parthe
rthenogenesis while
females (workers & queens)
que
develop from
fertilized eggs.
Parthenog
enogenesis
• Parthenogenesis occurs
curs in vertebrates in
some fishes, amphibian
bians, lizards, and has
recently been discovere
vered in snakes.
– After meiosis, the chromoso
osomes are doubled, creating
diploid “zygotes”.
– Often mating behavior iss required
req
to stimulate
development of offspring.
rtenogenesis yang kompleks yang
– Bereproduksi melalui parten
melibatkan penggandaan
n kromosom,
kr
contoh 15 spesies
kadal.
Hermaphrod
hroditism
• Hermaphroditism occurs
when an organism has
both male and female
reproductive systems.
– Monoecious
– Some can fertilize
themselves.
– Usually a mate is
required – they can
fertilize each other.
Sequential Herma
ermaphroditism
• In sequential
hermaphroditism, an
individual reverses its sex
during its lifetime.
– In wrasses, sex reversal is
associated with age, size
and social conditions.
– Fish are female first.
– The largest female
becomes male if the
previous male dies.
Sequential Herm
ermaphroditism
• There are also sequenti
ential hermaphrodites
that are male first, later
ater changing to female.
• This occurs in species
es th
that produce more eggs
at a bigger size – so it is advantageous to have
larger females.
– Oysters
Perbalikan jenis
is kel
kelamin pada ikan
karang,
g, wrasse
w
• Semua spesies pada ika
ikan ini terlahir betina,
tetapi indvidu yang tert
tertua dan terbesar
mengalami perubahan
an kkelamin menjadi dan
menyelesaikan kehidup
dupannya sebagai jantan
• Perubahan jenis kelamin
amin dikaitkan dengan
ukuran tubuh
Fertilizati
lization
• Fertilization – fusion of
egg and sperm into a
single diploid cell, the
zygote.
– External
– Internal
External Ferti
ertilization
• External fertilization –
fertilization takes place
outside the female’s
body.
– A wet environment is
required so gametes
don’t dry out and so
sperm may swim to
the eggs.
Ensuring Surviva
vival of Offspring
• Species with external
al fe
fertilization produce
huge quantities of game
ametes that result in lots
of zygotes.
– Predation on young is high.
hi
– Few will survive to repro
eproduce.
Ensuring Survival
ival of
o Offspring
• Species with internal
fertilization produce fewer
zygotes, but protect them
more from predation.
– Tough eggshells
– Embryo may develop in
reproductive tract of
female
– Parental care of eggs &
offspring
(Kutu air raksasa)
Perlindungan telur
telu pada Kutu air
raksa
aksasa
• Kutu air raksasa menghasilk
asilkan keturunan dalam
jumlah relatif sedikit tetapi
tapi perlindungan dari induk
meningkatkan kelangsunga
ngan hidup keturunan
tersebut
• Fertilisasi internal dan betin
etina menempelkan telur
yang sudah dibuahi ke bagian
bagi belakang jantan
• Kutu air jantan membawa
wa ttelurnya dan menjaganya
supaya tetap lembab dan
an terhindar
te
dari parasit.
Advantages of Sexu
Sexual Reproduction
• Sexual reproduction has costs including
finding mates, greater
ter energy
e
cost, reduced
proportion of genes pas
passed on to offspring,
and slower population
ion growth.
g
• However, sexual reprod
roduction increases
variability in the popula
pulation – important
during times of environ
ironmental change.
TUGASS kelompok
kel
•
•
•
•
•
•
•
TIAP KELOMPOK MEMB
EMBAHAS
1. PARTHENOGENESIS
2. BUDDING
3.FRAGMENTATION
4. BINER FUSION
5.EXTERNAL FERTILIZAT
IZATION(ikan, katak)
6. Hermafrodit
Gamete Producti
uction & Delivery
• Gametes (eggs & sperm
erm) are required for
sexual reproduction.
• Usually, gametes aree produced
pro
in gonads
(ovaries & testes).
• Germ cells are set aside
side early in
development. They will produce only
gametes.
Migration off Germ
Ger Cells
• Germ cells arise in the
yolk-sac endoderm of
vertebrates – not in
the gonads.
• They migrate to the
gonads using
amoeboid movement.
Gametog
etogenesis
• Gametogenesis – thee pr
production of gametes.
– Spermatogenesis – each primary spermatocyte
divides to form 4 sperm.
rm.
– Oogenesis – each primar
imary oocyte divides to form 1
ovum and 2-3 polar bodies.
bodi
• In oogenesis, cytokinesis
esis is unequal, most of the
cytoplasm goes to onee daughter
d
cell which becomes
the ovum. The other cells,
cell polar bodies, degenerate.
Spermatog
atogenesis
• Outermost layer of the seminiferous tubules
contain spermatogonia
nia, diploid cells that
grow to become primar
imary spermatocytes.
• After the first meiotic
tic division,
di
they are called
secondary spermatocyt
ocytes.
• When meiosis is comple
mplete the haploid cells
are spermatids.
Spermatog
atogenesis
Spermatogen
togenesis
• Spermatids mature
into motile sperm with
a tail for locomotion,
and a head containing
an acrosome as well as
the nucleus.
Oogen
genesis
• In the ovary, early germ cells
cel called oogonia are
diploid.
• Oogonia grow to becomee primary oocytes.
• After the first meiotic divisi
ivision, the cytoplasm divides
unequally and only one secondary
sec
oocyte and one
polar body result.
• Following the second meiot
eiotic division, one ootid and
another polar body result.
ult.
• The ootid develops into a functional
fu
ovum.
Oogen
genesis
Oogen
genesis
• Meiosis is usually arrest
rrested at the beginning of
meiosis and is not comp
ompleted until ovulation
or fertilization.
Reproductive
ctive Patterns
• Oviparous – animals that
at lay
la eggs.
– Most invertebrates, many
ny vertebrates
ve
• Ovoviviparous – animals
ls that
th retain the eggs within
their bodies. Nourishment
ent ccomes from the egg.
– Some annelids, insects, som
some fishes, reptiles.
• Viviparous – eggs develop
lop in
i oviduct or uterus,
nourishment from mother.
her.
– Mammals, some sharks,
s, scorpions.
sco
Invertebrate Reprodu
roductive Systems
• Many insects have
separate sexes,
internal fertilization
and have complex
reproductive systems.
– Female crickets use
long ovipositors to
deposit eggs.
Gamete Producti
uction & Delivery
• In vertebrates, reprodu
roductive systems are
similar with a few impo
important variations.
– Nonmammalian verteb
rtebrates usually have one
combined opening, the cloaca, for the digestive,
excretory, and reproduc
oductive systems.
– The uterus is partly or completely
c
divided into
two chambers in most
ost vvertebrates.
• Humans & other mamm
ammals with few young, birds &
snakes have a singlee structure.
str
Female Reproduc
ductive System
• Ovaries are where female gametes,
gam
egg cells, are
produced.
cel as well as follicle cells that
– A follicle contains one egg cell
nurture the developing egg.
– Most/all of the follicles a woman
wom will produce have formed
before birth.
Female Reprodu
roductive System
• Each month from puber
uberty through
menopause one follicle
licle ruptures and releases
its egg cell – ovulation
tion.
– The corpus luteum form
orms from the ruptured
follicle and secretes estrogen
estr
and progesterone to
help maintain the uterin
erine lining during pregnancy.
If the egg is not fertilized
lized the lining disintegrates.
Female Reproduc
ductive System
• After ovulation, the eggg le
leaves the ovary and
enters the oviduct, which
ich it follows to the uterus.
Male Reproduc
oductive System
• Testes are where male
ale ggametes, sperm cells,
are produced.
miniferous tubules where
– Testes contain the semin
sperm are formed.
– Leydig cells scattered
d between
be
the tubules
produce testosterone & other androgens.
– Sperm production can’t
n’t occur at normal body
temperature in mammal
mals, so the testes are held
outside the body abdom
dominal cavity in the scrotum.
Male Reproducti
uctive System
• After leaving the
testes, sperm pass
through the
epididymis where they
become motile and
gain the ability to
fertilize an egg.
• Sperm leave the body
through the vas
deferens and urethra.
Reproductiv
uctive Cycles
• Males produce sperm
m continuously,
c
whereas
females only releasee one
on or a few eggs at
certain intervals.
Reproductive Cycles
es in Female Mammals
• Humans & some other
her primates
p
have a
menstrual cycle while
ile o
other mammals have
an estrous cycle.
– In both, ovulation occurs
curs at a time when the
endometrial lining off the uterus is ready for an
embryo to implant.
– If no egg is fertilized,, the lining is shed
(menstruation) in human
mans & other primates and is
reabsorbed in other mammals.
mam
Reproductive Cycles
es in Female Mammals
• Female mammals that
at have
h
estrous cycles
may have more behavio
avioral changes.
• Estrous cycles may be m
more closely tied to
season and climate.
• Females will usually only
onl mate when in estrus
– the time surrounding
ing ovulation.
Female Reprod
roductive Cycle
• The female reproductive
ctive cycle in humans
contains two parts:
– Uterine (menstrual) cycle
– Ovarian cycle
• One integrated cyclee involving
inv
the uterus &
ovaries.
Female Reproductive
ctive Cycle
• The ovarian and
uterine cycles are
regulated by changing
hormone levels in the
blood.
The Ovaria
varian Cycle
• GnRH (gonadotropin-re
releasing hormone) is
released from the hypo
ypothalamus which
stimulates the release
se of
o LH (luteinizing
hormone) and FSH (follicle
(folli stimulating
hormone) from the pituitary
pitu
gland.
• FSH stimulates follicle
le growth,
g
aided by LH.
• The follicle cells start
rt producing
pr
estrogen.
– Rise in estrogen during
ing the
t follicular phase.
The Ovaria
varian Cycle
• When the secretion of estrogen
e
begins to rise
steeply, the release of FSH
F and LH rise rapidly
as well.
– Low levels of estrogen
n in
inhibit FSH & LH
production.
en sstimulate FSH & LH
– High levels of estrogen
production. (Positive feedback)
fee
The Ovaria
varian Cycle
• The maturing folliclee develops
de
an internal
fluid filled cavity and
d gro
grows very large.
– The follicular phase ends with ovulation. The
follicle ruptures releasing
asing the secondary oocyte.
The Ovaria
varian Cycle
• Following ovulation,, du
during the luteal phase,
LH stimulates transform
formation of the follicle
into the corpus luteum
um.
– The corpus luteum secre
ecretes estrogen and
progesterone.
th
hormones rises,
– As the combination of these
GnRH production in the hypothalamus is inhibited.
(Negative feedback)
The Ovaria
varian Cycle
• At the end of the luteal
teal phase, the corpus
luteum disintegratess and
an production of
estrogen and progestero
sterone drops.
• Now, the hypothalamus
mus will start producing
GnRH and the cycle star
starts over.
The Uterin
terine Cycle
• Estrogen and progestero
sterone secreted in the
ovary affect the uterus.
rus.
• Increasing amounts of eestrogen released by
the growing follicless cau
causes the lining of the
uterus (endometrium)) to
t thicken.
– The follicular phase of the
th ovarian is coordinated
with the proliferative
e phase
ph
of the uterine cycle.
The Uterin
terine Cycle
• After ovulation, estroge
rogen & progesterone
stimulate the maintenan
enance of the lining and
growth of endometrial
rial gglands that secrete
nutrient fluid to sustain
tain an embryo before
implantation.
– The luteal phase of the
he ovarian
o
cycle and the
secretory phase of the
he u
uterine cycle are
coordinated.
The Uterin
terine Cycle
• If the egg is not fertilize
ilized, the corpus luteum
disintegrates, and produ
roduction of estrogen and
progesterone drops sha
sharply. This triggers
breakdown of the endo
ndometrium –
menstruation.
Male Reproduc
oductive System
• In males, the principle
ple ssex hormones are
androgens, including testosterone.
te
– Produced mainly by Leydig
Ley cells in the testes.
– Responsible for seconda
ndary sexual characteristics.
– Important determinants
ants of behavior in
vertebrates.
• Sex drive
• Aggression
• Calling in birds & frogs
Male Reproducti
uctive System
• As in females, GnRH
from the
hypothalamus
stimulates release of
FSH and LH from the
pituitary.
– FSH promotes
spermatogenesis.
– LH stimulates Leydig
cells to make
testosterone.
Pregnan
nancy
• Conception,
fertilization of the
egg, occurs in the
oviduct.
– Results in zygote.
• Cleavage, rapid
mitotic divisions,
starts after 24 hrs.
Pregna
egnancy
• After about a week,, the ball of cells produced
during cleavage develop
elops a cavity and is now
called a blastocyst.
• It then implants into
o the endometrium.
Pregna
egnancy
• The embryo secretess hormones
ho
including
human chorionic gonad
nadotropin (hCG) that act
like LH to maintain secre
secretion of progesterone
and estrogen to maintai
intain the lining of the
uterus.
First Trim
Trimester
• For the first few weeks
eks tthe embryo gets
nutrients from the endo
ndometrium.
• The outer layer of the
he b
blastocyst – the
trophoblast grows into the endometrium and
forms the placenta.
Placental Circulation
Circ
• The placenta contains clos
closely entwined embryonic
& maternal blood vessels
els for
f the exchange of
nutrients and wastes.
Hormone
ne LLevels
• hCG is produced by the
placenta.
• Estrogen and
progesterone are
produced by the
corpus luteum, then by
the placenta.
First Trim
Trimester
• Organogenesis is occurr
curring during the first
trimester.
– The heart starts beating
ting about the fourth week.
– At 8 weeks, all majorr organs
org
are present in
rudimentary form.
• Now called a fetus.
Second Trimester
Trim
• The fetus grows to about
ut 30
3 cm and is very active.
• Hormone levels stabilize,
ize, h
hCG declines, the corpus
luteum disintegrates and
nd the
t placenta takes over
production of progesteron
erone.
Third Trim
Trimester
• Fetal activity may decre
ecrease as space becomes
limited.
– Fetus grows to aboutt 50 cm and 3-4 kg.
• Development of organs
ans is completed.
• Neural developmentt continues
co
even after
birth.
Labor & Delivery
Del
• Birth, parturition,
occurs through strong
rhythmic contractions
of the uterus.
– Dilation
– Expulsion
– Delivery of placenta
Lactat
ctation
• One defining characteri
teristic of mammals is
that we have mammary
ary glands.
• After birth, progesteron
erone levels fall
stimulating the product
duction of prolactin which
stimulates milk product
duction.
– The release of milk iss controlled
con
by oxytocin.
Multiple
le Births
B
• Humans are usually
uniparous – one offspring
ng
at a time.
– Multiparous animals
have several.
• Fraternal twins result
from ovulation &
fertilization of two eggs.
• Identical twins result
from the splitting of one
zygote.
YANG
RELEVAN
Latar Belakang
gai berikut :
• Pada K-13 terdapat KD sebagai
3.2 Memahami reproduksi pada tumbuhan
tum
dan hewan, sifat
keturunan, serta kelangsungan
an makhluk hidup
4.2 Menyajikan karya hasil perkemb
embangbiakan pada tumbuhan
• Kemampuan apa saja yang haru
arus dilatihkan ke siswa?
• Materi apa saja yang harus dipe
ipelajari siswa?
• Bagaimana kegiatan belajar yang sesuai dengan kemampuan
dan materi tersebut?
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Application
ation – 80’
"
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1
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3.2 Memahami reproduksi pada
da tumbuhan dan hewan, sifat
keturunan, serta kelangsungan makhluk
m
hidup
4.2 Menyajikan karya hasil perke
kembangbiakan pada tumbuhan
2
3
*
KD 3.3
KD 4.3
Berbagi Gagasan
•Sajikanlah hasil diskusi kelom
kelompok Saudara
kepada kelompok lain
•Kelompok lain: Berikan komentar,
kom
khususnya
terkait KETEPATAN jawaban
an aatas pertanyaan
tadi.
SISTEM REPRODUK
DUKSI TUMBUHAN
• Vegetatif (asexual)
Lebih sering terjadi
pada Tumbuhan.
Tidak melibatkan
pertemuan gamet
jantan dan gamet
betina.
• Generatif (sexual)
Terjadi baik pada
Tumbuhan maupun
Hewan
Melibatkan pertemuan
gamet jantan dan
betina.
BEBERAPA CONTOH REPRODUK
DUKSI SECARA VEGETATIF ALAMI
DAN BUATAN PAD
PADA TUMBUHAN
•
Alami
1. Tunas (pisang, tebuh, pohon
pinang dan bambu).
2. Spora (Lumut dan tumbuhan
paku)
3. Tunas adventif (cocor bebek)
4. Stolon / geragih (pegagan,
strawberry, semanggi)
5. Rizoma / rimpang (Kunyit, jahe,
Bangle, lengkuas dan tebuh.
6. Umbi batang (kentang, ubi jalar)
7. Umbi lapis (bawang-bawangan
dan bunga tulip).
• Buatan
Mencangkok
Menempel/Okulasi
Menyambung atau Enten
Merunduk
Stek
Kultur jaringan
Asexual Reproduction
Repr
• Asexual reproduction
tion is natural “cloning.”
Parts of the plant, suc
such as leaves or stems,
produce roots and become
bec
an independent
plant.
Sexual Repr
eproduction
• Sexual reproduction
on re
requires fusion of male
cells in the pollen grai
grain with female cells in
the ovule.
Pergiliran
n Ke
Keturunan
• Plants have a double
ble llife cycle with two
distinct forms:
– Sporophyte: produce
ce diploid
d
spores by mitosis.
– Gametophyte: produce
uce gametes by meiosis
Reproduksii Generatif
Gen
pada
Tumbu
mbuhan
Flower
er Parts
P
Klasifikasi
ikasi Bunga
• Bunga lengkap dan bunga
bun tak lengkap
• Bunga sempurna dan
n Bu
Bunga tidak sempurna
MACAM MACAM
AM PENYERBUKAN
BERDASARKAN ASAL
ASA SERBUK SARI
•
•
•
•
Penyerbukan sendiri (aut
autogami)
Penyerbukan tetangga(ge
geitonogami)
Penyerbukan silang(allog
llogami / xenogami)
Penyerbukan bastar (hyb
hybridogami)
MACAM MACAM
AM PENYERBUKAN
BERDASARKAN VEKTOR/PERANTARA.
VEKT
Anemogami (perantaraan
raan angin).
Hidrogami (perantaraan
aan air).
Antropogami (perantaraa
taraan manusia).
Zoidiogami (perantaraan
raan hewan).
siput
serangga
kelelawar
burung
: malakogami
mi
: entomogami
ami
: kiropterogam
gami
: ornitogami
Perkembangan Gener
neratif pada Tumbuhan
•
•
•
•
Konjugasi, yaitu reproduksi generatif
ratif pada tumbuhan yang belum jelas alat
kelaminnya. Contoh: Spyrogyra (ganggang
(gan
hijau) yang koloninya berbentuk
benang.
amet atau kelamin yang sama besar.
Isogami, yaitu peleburan 2 sel game
Contoh:Clamydomonas (ganggang
ng biru)
b
Anisogami, yaitu peleburan 2 sell gamet
gam yang besarnya tidak sama. Gamet
1 lebih kecil (mikrogamet) dan game
amet 2 lebih besar (makrogamet). Contoh:
Ulva (ganggang yang berbentuk lem
lembaran).
Penyerbukan yang diikuti dengan
n pembuahan.
pe
Terjadi pada tumbuhan
berbunga (Antophyta) atau tumbuha
buhan berbiji (Spermatophyta). Alat
kelamin jantan berupa benang sari
ari dan
d alat kelamin betinanya berupa
putik.
MACAM – MACAM
CAM PEMBUAHAN
• GYMNOSPERMAE
terjadi pembuahan
tunggal ( hanya
terbentuk biji)
• ANGIOSPERMAE
terjadi pembuahan
ganda ( terbentuk biji
dan buah)
Angiosperm
erm Life Cycle
Gametogenes
genesis: Male
Gametogenes
enesis: Female
Doublee Fertilization
Fert
LIFE CYCLE
LE O
OF PINUS
STROBI
OBILUS
• Strobilus yang telah
pecah.
• Strobilus yang belum
pecah
TUGAS KELOMPOK
KEL
• Tiap kelompok
Flower
er to Fruit
Ovule
le to Seed
Seed Ana
Anatomy
Seed Germ
ermination
• Umbi bawang merah meng
engandung senyawa
turunan asam amino yang
ang mengandung sulfur yaitu
Sikloalliin 2%, propilalliin
liin dan
d propenilalliin. Bila selsel umbi pecah senyawaa tersebut
te
akan berubah
menjadi bentuk ester ( ester
est asam tiosulfinat),
sulfinil disulfida (Kepaen),
en), disulfida dan polisulfida,
begitu juga tiofen. Di samp
amping itu terbentuk pula
propantial-S-oksida (suatu
atu senyawa yang dapat
menyebabkan keluarnya
ya aair mata).
Disamping turunan asam
am amino,
a
ditemukan pula
adenosine dan prostagland
landin.8,11)
• www.wou.edu
• Buku solomon
Animal Reprodu
oductive Process
Reproduct
duction
• Reproduction is one off the ubiquitous properties of
life.
• Evolution is inextricably
ly linked
lin
to reproduction.
• Two modes of reproductio
ction are recognized:
– Asexual
– Sexual
Asexual vs. Sexua
xual Reproduction
• Asexual reproduction – the production of
offspring whose genes
es aall come from one
parent without the fusio
fusion of egg and sperm.
– Usually diploid eggs are produced by mitosis
which then develop dire
directly.
Asexual vs. Sexual
ual R
Reproduction
• Sexual reproduction – the
production of offspring by
the fusion of haploid
gametes (eggs & sperm)
from two parents to form
a diploid zygote (fertilized
egg).
– Gametes arise by meiosis.
– Genetic variability is
increased by the random
combinations of genes from
the parents.
Asexual Repro
eproduction
• Bacteria and many
protozoa can
reproduce by
binary fission –
separating into two
or more individuals
approximately the
same size.
Asexual Repro
eproduction
• Budding is a form of
asexual reproduction
where new individuals
form as offshoots of a
parent.
• The offspring may
separate or remain
attached to form
colonies.
Asexual Reproduction
Repr
• Freshwater sponges rele
release specialized
groups of cells called gemmules
ge
that can
grow into new individua
iduals.
Asexual Reproduction
Repr
• Fragmentation results
ults w
when an organism’s
body is broken into sev
several pieces and each
piece grows into a new organism.
– Regeneration – the regr
regrowth of lost body parts.
Asexual Repro
eproduction
• Fragmentation occurs
in some sponges,
cnidarians, polychaete
annelids, tunicates.
– Sea stars can
regenerate lost limbs,
but only species in the
genus Linckia can form
new individuals from
broken arms.
Asexual Reproduction
ction - Advantages
• Animals living far from memb
mbers
of their own species can
reproduce without having to
search for a mate.
• Numerous offspring quickly –
ideal for colonizing a new area
area.
• Advantageous in a stable,
favorable environment because
cause
it reproduces a successful
genotype precisely.
Sexual Repr
eproduction
• Generally involves two parents.
pare
• Special germ cells unite to fform a zygote.
• Sexual reproduction recom
combines parental characters.
– A richer, more diversified
d population
po
results.
• In haploid asexual organism
nisms mutations are
expressed and selected quickly.
qui
• In sexual reproduction a normal
no
gene on the
homologous chromosome
me m
may mask a gene
mutation.
Sexual Repr
eproduction
• Why do so many animals
ls re
reproduce sexually rather
than asexually?
• The costs of sexual reprodu
roduction are greater than
asexual methods:
–
–
–
–
More complicated.
Requires more time.
Uses more energy.
The cost of meiosis to thee female
fe
is passage of only half of
her genes to offspring.
uces resources for females that
– Production of males reduce
could produce eggs.
Sexual Repr
eproduction
• However:
ce more
m
novel genotypes to
– Sexual organisms produce
survive in times of environm
onmental change.
– In crowded habitats, selectio
ection is intense and diversity
prevents extinction.
– On a geological time scale
le sexual
se
lineages with less
variation are prone to extinc
xtinction.
– Many invertebrates with both
bo sexual and asexual modes
enjoy the advantages of both.
bot
Parthenog
enogenesis
• Parthenogenesis involv
volves the development of
an embryo from an unfe
unfertilized egg or one
where sperm & egg nuclei
nuc did not fuse.
– Ameiotic parthenogene
enesis – no meiosis, egg is
formed by mitosis (diplo
iploid)
– Meiotic parthenogenesi
nesis – haploid ovum formed
by meiosis, it may be activated
act
by a male (or not).
Parthenog
enogenesis
• In some animals (aphids
hids (kutu daun), rotifers,
Daphnia (crustacea air ttawar)) the females
can produce two types
pes of
o eggs depends on
environment condition.
ion.
– One must be fertilized.
– One type will develop direct
irectly into haploid adults –
parthenogenesis.
duce eggs by mitosis.(hewan
• Haploid females produce
dewasa yang dihasilkan
an bersifat
b
haploid) dan sel-selnya
tidak mengalami miosis
sis dalam
d
pembentukan telur
baru.
Parthenog
enogenesis
• Daphnia reproduce asexually
lly (parthenogenesis)
(p
when
conditions are favorable.
antung musim, reproduksi
• pergantian reproduksi tergantu
aseksual terjadi pada kondisi
isi yang
ya menguntungkan dan
reproduksi seksual terjadi ketik
etika adanya cekaman lingkungan.
• In times of environmental stress,
tress, they utilize sexual
reproduction.
– Increases variation!
Parthenog
enogenesis
• In many social insects,
ts, like
l honeybees, males
(drones) (lebah madu
du ja
jantan) are haploid and
are produced by parthe
rthenogenesis while
females (workers & queens)
que
develop from
fertilized eggs.
Parthenog
enogenesis
• Parthenogenesis occurs
curs in vertebrates in
some fishes, amphibian
bians, lizards, and has
recently been discovere
vered in snakes.
– After meiosis, the chromoso
osomes are doubled, creating
diploid “zygotes”.
– Often mating behavior iss required
req
to stimulate
development of offspring.
rtenogenesis yang kompleks yang
– Bereproduksi melalui parten
melibatkan penggandaan
n kromosom,
kr
contoh 15 spesies
kadal.
Hermaphrod
hroditism
• Hermaphroditism occurs
when an organism has
both male and female
reproductive systems.
– Monoecious
– Some can fertilize
themselves.
– Usually a mate is
required – they can
fertilize each other.
Sequential Herma
ermaphroditism
• In sequential
hermaphroditism, an
individual reverses its sex
during its lifetime.
– In wrasses, sex reversal is
associated with age, size
and social conditions.
– Fish are female first.
– The largest female
becomes male if the
previous male dies.
Sequential Herm
ermaphroditism
• There are also sequenti
ential hermaphrodites
that are male first, later
ater changing to female.
• This occurs in species
es th
that produce more eggs
at a bigger size – so it is advantageous to have
larger females.
– Oysters
Perbalikan jenis
is kel
kelamin pada ikan
karang,
g, wrasse
w
• Semua spesies pada ika
ikan ini terlahir betina,
tetapi indvidu yang tert
tertua dan terbesar
mengalami perubahan
an kkelamin menjadi dan
menyelesaikan kehidup
dupannya sebagai jantan
• Perubahan jenis kelamin
amin dikaitkan dengan
ukuran tubuh
Fertilizati
lization
• Fertilization – fusion of
egg and sperm into a
single diploid cell, the
zygote.
– External
– Internal
External Ferti
ertilization
• External fertilization –
fertilization takes place
outside the female’s
body.
– A wet environment is
required so gametes
don’t dry out and so
sperm may swim to
the eggs.
Ensuring Surviva
vival of Offspring
• Species with external
al fe
fertilization produce
huge quantities of game
ametes that result in lots
of zygotes.
– Predation on young is high.
hi
– Few will survive to repro
eproduce.
Ensuring Survival
ival of
o Offspring
• Species with internal
fertilization produce fewer
zygotes, but protect them
more from predation.
– Tough eggshells
– Embryo may develop in
reproductive tract of
female
– Parental care of eggs &
offspring
(Kutu air raksasa)
Perlindungan telur
telu pada Kutu air
raksa
aksasa
• Kutu air raksasa menghasilk
asilkan keturunan dalam
jumlah relatif sedikit tetapi
tapi perlindungan dari induk
meningkatkan kelangsunga
ngan hidup keturunan
tersebut
• Fertilisasi internal dan betin
etina menempelkan telur
yang sudah dibuahi ke bagian
bagi belakang jantan
• Kutu air jantan membawa
wa ttelurnya dan menjaganya
supaya tetap lembab dan
an terhindar
te
dari parasit.
Advantages of Sexu
Sexual Reproduction
• Sexual reproduction has costs including
finding mates, greater
ter energy
e
cost, reduced
proportion of genes pas
passed on to offspring,
and slower population
ion growth.
g
• However, sexual reprod
roduction increases
variability in the popula
pulation – important
during times of environ
ironmental change.
TUGASS kelompok
kel
•
•
•
•
•
•
•
TIAP KELOMPOK MEMB
EMBAHAS
1. PARTHENOGENESIS
2. BUDDING
3.FRAGMENTATION
4. BINER FUSION
5.EXTERNAL FERTILIZAT
IZATION(ikan, katak)
6. Hermafrodit
Gamete Producti
uction & Delivery
• Gametes (eggs & sperm
erm) are required for
sexual reproduction.
• Usually, gametes aree produced
pro
in gonads
(ovaries & testes).
• Germ cells are set aside
side early in
development. They will produce only
gametes.
Migration off Germ
Ger Cells
• Germ cells arise in the
yolk-sac endoderm of
vertebrates – not in
the gonads.
• They migrate to the
gonads using
amoeboid movement.
Gametog
etogenesis
• Gametogenesis – thee pr
production of gametes.
– Spermatogenesis – each primary spermatocyte
divides to form 4 sperm.
rm.
– Oogenesis – each primar
imary oocyte divides to form 1
ovum and 2-3 polar bodies.
bodi
• In oogenesis, cytokinesis
esis is unequal, most of the
cytoplasm goes to onee daughter
d
cell which becomes
the ovum. The other cells,
cell polar bodies, degenerate.
Spermatog
atogenesis
• Outermost layer of the seminiferous tubules
contain spermatogonia
nia, diploid cells that
grow to become primar
imary spermatocytes.
• After the first meiotic
tic division,
di
they are called
secondary spermatocyt
ocytes.
• When meiosis is comple
mplete the haploid cells
are spermatids.
Spermatog
atogenesis
Spermatogen
togenesis
• Spermatids mature
into motile sperm with
a tail for locomotion,
and a head containing
an acrosome as well as
the nucleus.
Oogen
genesis
• In the ovary, early germ cells
cel called oogonia are
diploid.
• Oogonia grow to becomee primary oocytes.
• After the first meiotic divisi
ivision, the cytoplasm divides
unequally and only one secondary
sec
oocyte and one
polar body result.
• Following the second meiot
eiotic division, one ootid and
another polar body result.
ult.
• The ootid develops into a functional
fu
ovum.
Oogen
genesis
Oogen
genesis
• Meiosis is usually arrest
rrested at the beginning of
meiosis and is not comp
ompleted until ovulation
or fertilization.
Reproductive
ctive Patterns
• Oviparous – animals that
at lay
la eggs.
– Most invertebrates, many
ny vertebrates
ve
• Ovoviviparous – animals
ls that
th retain the eggs within
their bodies. Nourishment
ent ccomes from the egg.
– Some annelids, insects, som
some fishes, reptiles.
• Viviparous – eggs develop
lop in
i oviduct or uterus,
nourishment from mother.
her.
– Mammals, some sharks,
s, scorpions.
sco
Invertebrate Reprodu
roductive Systems
• Many insects have
separate sexes,
internal fertilization
and have complex
reproductive systems.
– Female crickets use
long ovipositors to
deposit eggs.
Gamete Producti
uction & Delivery
• In vertebrates, reprodu
roductive systems are
similar with a few impo
important variations.
– Nonmammalian verteb
rtebrates usually have one
combined opening, the cloaca, for the digestive,
excretory, and reproduc
oductive systems.
– The uterus is partly or completely
c
divided into
two chambers in most
ost vvertebrates.
• Humans & other mamm
ammals with few young, birds &
snakes have a singlee structure.
str
Female Reproduc
ductive System
• Ovaries are where female gametes,
gam
egg cells, are
produced.
cel as well as follicle cells that
– A follicle contains one egg cell
nurture the developing egg.
– Most/all of the follicles a woman
wom will produce have formed
before birth.
Female Reprodu
roductive System
• Each month from puber
uberty through
menopause one follicle
licle ruptures and releases
its egg cell – ovulation
tion.
– The corpus luteum form
orms from the ruptured
follicle and secretes estrogen
estr
and progesterone to
help maintain the uterin
erine lining during pregnancy.
If the egg is not fertilized
lized the lining disintegrates.
Female Reproduc
ductive System
• After ovulation, the eggg le
leaves the ovary and
enters the oviduct, which
ich it follows to the uterus.
Male Reproduc
oductive System
• Testes are where male
ale ggametes, sperm cells,
are produced.
miniferous tubules where
– Testes contain the semin
sperm are formed.
– Leydig cells scattered
d between
be
the tubules
produce testosterone & other androgens.
– Sperm production can’t
n’t occur at normal body
temperature in mammal
mals, so the testes are held
outside the body abdom
dominal cavity in the scrotum.
Male Reproducti
uctive System
• After leaving the
testes, sperm pass
through the
epididymis where they
become motile and
gain the ability to
fertilize an egg.
• Sperm leave the body
through the vas
deferens and urethra.
Reproductiv
uctive Cycles
• Males produce sperm
m continuously,
c
whereas
females only releasee one
on or a few eggs at
certain intervals.
Reproductive Cycles
es in Female Mammals
• Humans & some other
her primates
p
have a
menstrual cycle while
ile o
other mammals have
an estrous cycle.
– In both, ovulation occurs
curs at a time when the
endometrial lining off the uterus is ready for an
embryo to implant.
– If no egg is fertilized,, the lining is shed
(menstruation) in human
mans & other primates and is
reabsorbed in other mammals.
mam
Reproductive Cycles
es in Female Mammals
• Female mammals that
at have
h
estrous cycles
may have more behavio
avioral changes.
• Estrous cycles may be m
more closely tied to
season and climate.
• Females will usually only
onl mate when in estrus
– the time surrounding
ing ovulation.
Female Reprod
roductive Cycle
• The female reproductive
ctive cycle in humans
contains two parts:
– Uterine (menstrual) cycle
– Ovarian cycle
• One integrated cyclee involving
inv
the uterus &
ovaries.
Female Reproductive
ctive Cycle
• The ovarian and
uterine cycles are
regulated by changing
hormone levels in the
blood.
The Ovaria
varian Cycle
• GnRH (gonadotropin-re
releasing hormone) is
released from the hypo
ypothalamus which
stimulates the release
se of
o LH (luteinizing
hormone) and FSH (follicle
(folli stimulating
hormone) from the pituitary
pitu
gland.
• FSH stimulates follicle
le growth,
g
aided by LH.
• The follicle cells start
rt producing
pr
estrogen.
– Rise in estrogen during
ing the
t follicular phase.
The Ovaria
varian Cycle
• When the secretion of estrogen
e
begins to rise
steeply, the release of FSH
F and LH rise rapidly
as well.
– Low levels of estrogen
n in
inhibit FSH & LH
production.
en sstimulate FSH & LH
– High levels of estrogen
production. (Positive feedback)
fee
The Ovaria
varian Cycle
• The maturing folliclee develops
de
an internal
fluid filled cavity and
d gro
grows very large.
– The follicular phase ends with ovulation. The
follicle ruptures releasing
asing the secondary oocyte.
The Ovaria
varian Cycle
• Following ovulation,, du
during the luteal phase,
LH stimulates transform
formation of the follicle
into the corpus luteum
um.
– The corpus luteum secre
ecretes estrogen and
progesterone.
th
hormones rises,
– As the combination of these
GnRH production in the hypothalamus is inhibited.
(Negative feedback)
The Ovaria
varian Cycle
• At the end of the luteal
teal phase, the corpus
luteum disintegratess and
an production of
estrogen and progestero
sterone drops.
• Now, the hypothalamus
mus will start producing
GnRH and the cycle star
starts over.
The Uterin
terine Cycle
• Estrogen and progestero
sterone secreted in the
ovary affect the uterus.
rus.
• Increasing amounts of eestrogen released by
the growing follicless cau
causes the lining of the
uterus (endometrium)) to
t thicken.
– The follicular phase of the
th ovarian is coordinated
with the proliferative
e phase
ph
of the uterine cycle.
The Uterin
terine Cycle
• After ovulation, estroge
rogen & progesterone
stimulate the maintenan
enance of the lining and
growth of endometrial
rial gglands that secrete
nutrient fluid to sustain
tain an embryo before
implantation.
– The luteal phase of the
he ovarian
o
cycle and the
secretory phase of the
he u
uterine cycle are
coordinated.
The Uterin
terine Cycle
• If the egg is not fertilize
ilized, the corpus luteum
disintegrates, and produ
roduction of estrogen and
progesterone drops sha
sharply. This triggers
breakdown of the endo
ndometrium –
menstruation.
Male Reproduc
oductive System
• In males, the principle
ple ssex hormones are
androgens, including testosterone.
te
– Produced mainly by Leydig
Ley cells in the testes.
– Responsible for seconda
ndary sexual characteristics.
– Important determinants
ants of behavior in
vertebrates.
• Sex drive
• Aggression
• Calling in birds & frogs
Male Reproducti
uctive System
• As in females, GnRH
from the
hypothalamus
stimulates release of
FSH and LH from the
pituitary.
– FSH promotes
spermatogenesis.
– LH stimulates Leydig
cells to make
testosterone.
Pregnan
nancy
• Conception,
fertilization of the
egg, occurs in the
oviduct.
– Results in zygote.
• Cleavage, rapid
mitotic divisions,
starts after 24 hrs.
Pregna
egnancy
• After about a week,, the ball of cells produced
during cleavage develop
elops a cavity and is now
called a blastocyst.
• It then implants into
o the endometrium.
Pregna
egnancy
• The embryo secretess hormones
ho
including
human chorionic gonad
nadotropin (hCG) that act
like LH to maintain secre
secretion of progesterone
and estrogen to maintai
intain the lining of the
uterus.
First Trim
Trimester
• For the first few weeks
eks tthe embryo gets
nutrients from the endo
ndometrium.
• The outer layer of the
he b
blastocyst – the
trophoblast grows into the endometrium and
forms the placenta.
Placental Circulation
Circ
• The placenta contains clos
closely entwined embryonic
& maternal blood vessels
els for
f the exchange of
nutrients and wastes.
Hormone
ne LLevels
• hCG is produced by the
placenta.
• Estrogen and
progesterone are
produced by the
corpus luteum, then by
the placenta.
First Trim
Trimester
• Organogenesis is occurr
curring during the first
trimester.
– The heart starts beating
ting about the fourth week.
– At 8 weeks, all majorr organs
org
are present in
rudimentary form.
• Now called a fetus.
Second Trimester
Trim
• The fetus grows to about
ut 30
3 cm and is very active.
• Hormone levels stabilize,
ize, h
hCG declines, the corpus
luteum disintegrates and
nd the
t placenta takes over
production of progesteron
erone.
Third Trim
Trimester
• Fetal activity may decre
ecrease as space becomes
limited.
– Fetus grows to aboutt 50 cm and 3-4 kg.
• Development of organs
ans is completed.
• Neural developmentt continues
co
even after
birth.
Labor & Delivery
Del
• Birth, parturition,
occurs through strong
rhythmic contractions
of the uterus.
– Dilation
– Expulsion
– Delivery of placenta
Lactat
ctation
• One defining characteri
teristic of mammals is
that we have mammary
ary glands.
• After birth, progesteron
erone levels fall
stimulating the product
duction of prolactin which
stimulates milk product
duction.
– The release of milk iss controlled
con
by oxytocin.
Multiple
le Births
B
• Humans are usually
uniparous – one offspring
ng
at a time.
– Multiparous animals
have several.
• Fraternal twins result
from ovulation &
fertilization of two eggs.
• Identical twins result
from the splitting of one
zygote.