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Chapter 27
Reproduction and Embryonic Development
PowerPoint Lectures for
Biology: Concepts & Connections, Sixth Edition
Campbell, Reece, Taylor, Simon, and Dickey
Copyright © 2009 Pearson Education, Inc.
Lecture by Richard L. Myers
Translated by Nabih A. Baeshen
ASEXUAL AND SEXUAL
REPRODUCTION
Copyright © 2009 Pearson Education, Inc.
27.1 Asexual reproduction results in the generation of genetically
identical offspring
 Asexual reproduction
– One parent produces genetically identical offspring
– Very rapid reproduction
– Can proceed via
– Budding /
Asexual reproduction of an aggregating sea
anemone (Anthopleura elegantissima) by fission
– Fission /
– Fragmentation/regeneration
Copyright © 2009 Pearson Education, Inc.
27.2 Sexual reproduction results in the generation of genetically
unique offspring
 Some animals exhibit hermaphroditism
– One individual with male and female reproductive
systems
– Easier to find a mate for animals less mobile or solitary
Hermaphroditic
earthworms mating
Copyright © 2009 Pearson Education, Inc.
27.2 Sexual reproduction results in the generation of genetically
unique offspring
 Sperm may be transferred to the female by
– External fertilization
– Many fish and amphibian species
– Eggs and sperm are discharged near each other
– Internal fertilization
– Some fish and amphibian species
– Nearly all terrestrial animals
– Sperm is deposited in or near the female
reproductive tract
Frogs in an embrace that
triggers the release of
eggs and sperm
Copyright © 2009 Pearson Education, Inc.
HUMAN REPRODUCTION
Copyright © 2009 Pearson Education, Inc.
27.3 Reproductive anatomy of the human female
 Both sexes in humans have
– A set of gonads where gametes are
produced
– Ducts for gamete transport
– Structures for copulation
Copyright © 2009 Pearson Education, Inc.
27.3 Reproductive anatomy of the human female
 Ovaries contain follicles that Nurture eggs and
Produce sex hormones
 Oviducts convey eggs to the uterus where
embryos develop
 The uterus opens into the vagina through the
 The vagina
– Receives the penis during sexual intercourse
– Forms the birth canal
Copyright © 2009 Pearson Education, Inc.
Oviduct
Ovaries
Follicles
Corpus luteum
Wall of uterus
Uterus
Endometrium
(lining of uterus)
Cervix
(“neck” of uterus
Vagina
Front view of female reproductive anatomy (upper portion)
27.4 Reproductive anatomy of the human male
 Testes (singular testis) produce Sperm and Male
hormones
 Epididymis stores sperm as they develop further
 Several glands contribute to semen
– Seminal vesicles
– Prostate
– Bulbourethral
Copyright © 2009 Pearson Education, Inc.
Urinary
Bladder
Prostate gland
Seminal
Vesicle
(behind
Bladder)
Bulbourethral gland
Erectile tissue of penis
Vas deferens
Urethra
Scrotum
Epididymis
Testis
Glans of
Penis
Front view of male reproductive anatomy
27.4 Reproductive anatomy of the human male
 Sperm production
– Regulated by a negative feedback
system of hormones
– Involves the hypothalamus,
pituitary, and testes
Copyright © 2009 Pearson Education, Inc.
Stimuli from other
areas in the brain
Releasing
Hormone
Anterior
Pituitary
FSH
LH
Negative feedback
Hypothalamus
Androgen
production
Testis
Sperm production
Hormonal control of the testis
27.5 The formation of sperm and egg requires meiosis
 Spermatogenesis
– Occurs in seminiferous tubules
– Primary spermatocytes
– Formed by mitosis
– Divide by meiosis I to produce secondary
spermatocytes
– Secondary spermatocytes divide by meiosis II to
produce spermatids
– Round spermatids differentiate into elongate sperm
– Mature sperm released into seminiferous tubule
Copyright © 2009 Pearson Education, Inc.
Epididymis
Testis
Penis
Scrotum
Testis
Seminiferous
Tubule
Cross section of
seminiferous tubule
Diploid cell
Primary spermatocyte
(in prophase of Meiosis I)
Secondary spermatocyte
(haploid; double chromatids)
Developing sperm cells
(haploid; single chromatids)
Sperm cells
(haploid)
Center of seminiferous tubule
2n
Diploid cell
Differentiation and
onset of Meiosis I
2n
Primary spermatocyte
(in prophase of Meiosis I)
Meiosis I completed
n
Secondary spermatocyte
n
(haploid; double chromatids)
Meiosis II
n
n
n
n
Developing sperm cells
(haploid; single chromatids)
Differentiation
n
n
n
n
Sperm cells
(haploid)
27.5 The formation of sperm and egg requires meiosis
 Oogenesis
– Begins before birth: diploid cells start meiosis and
stop
– Each month about one primary oocyte resumes
meiosis
– A secondary oocyte arrested at metaphase of
meiosis II is ovulated
– Meiosis of the ovum is completed after
fertilization
Copyright © 2009 Pearson Education, Inc.
2n
Diploid cell in embryo
Differentiation
and onset of
Meiosis I
Ovary
2n
Completion
of Meiosis I
and onset of
Meiosis II
n
Entry of sperm
triggers completion
of Meiosis II
Primary oocyte
(arrested in prophase
of Meiosis I; present
at birth)
Corpus
First
n polar body
luteum
Secondary oocyte
(arrested at metaphase of Meiosis II;
released from ovary)
Growing
Follicle
n Second
polar body
n
Ovum
(haploid)
Mature follicle
Sperm
Ovulation
Ruptured follicle
Oogenesis and the development of an ovarian follicle
27.6 Hormones synchronize cyclic changes in the ovary
and uterus
 Ovarian and menstrual cycles
– Occur about every 28 days
– Hypothalamus signals the anterior pituitary to
secrete follicle-stimulating hormone (FSH) and
leuteinizing hormone (LH), which trigger
– Growth of a follicle
– Ovulation
Copyright © 2009 Pearson Education, Inc.
27.6 Hormones synchronize cyclic changes in the ovary and uterus
 After ovulation, ovarian follicle becomes corpus
luteum
 Corpus luteum secretes estrogen and
progesterone, which
– Stimulate the endometrium to thicken
– Prepare the uterus for implantation of the
embryo
– Inhibit hypothalamus, reducing FSH and LH
secretion
Copyright © 2009 Pearson Education, Inc.
27.6 Hormones synchronize cyclic changes in the ovary and uterus
 If egg is fertilized
– Developing embryo releases hormones(human chorionic
gonadotropin) that maintain the corpus luteum which
continue to secrete progesterone and estrogen
maintaining uterine lining to complete the pregnancy.
– Menstruation does not occur
 If egg is not fertilized
– Drop in LH shuts down corpus luteum and stop secreting
its hormones(progesterone and estrogen )
– Menstruation is triggered
– Hypothalamus and pituitary stimulate development of a
new follicle
Copyright © 2009 Pearson Education, Inc.
PRINCIPLES OF
EMBRYONIC DEVELOPMENT
Copyright © 2009 Pearson Education, Inc.
27.9 Fertilization results in a zygote and triggers embryonic development
 Embryonic development begins with fertilization
– The union of sperm and egg
– To form a diploid zygote
 Sperm are adapted to reach and fertilize an egg
 Streamlined shape moves more easily through
fluids
 Many mitochondria provide ATP for tail movements
 Head contains a haploid nucleus Tipped with an
acrosome containing penetrating enzymes
Copyright © 2009 Pearson Education, Inc.
Neck
Plasma membrane
Head
Middle piece
Tail
Mitochondrion
(spiral shape)
Nucleus
Acrosome
The structure of a human sperm cell
27.9 Fertilization results in a zygote and triggers embryonic
development
 Fertilization events
– Sperm squeeze past follicle cells
– Acrosomal enzymes pierce egg’s coat
– Sperm binds to vitelline layer
– Sperm and egg plasma membranes fuse
– Egg is stimulated to develop further
– Egg and sperm nuclei fuse(become diploid)
Copyright © 2009 Pearson Education, Inc.
1
The sperm squeezes
through cells left
over from the follicle
2
The sperm’s
acrosomal
enzymes digest the
egg’s jelly coat
3
Proteins on the
sperm head bind to
egg receptors
4
Sperm
Nucleus
Plasma
membrane
The plasma membranes
of sperm and egg fuse
5
Acrosomal
enzymes
The sperm nucleus
enters the egg
cytoplasm
Acrosome
Sperm
head
6
A fertilization
envelope
forms
Receptor protein molecules
Plasma
membrane
Sperm
nucleus
Vitelline layer
‫الطبقة المحيه‬
Cytoplasm
Jelly coat
‫الغالف الهالمي‬
Egg
nucleus
7
The nuclei
of sperm and egg fuse
Egg cell
Zygote nucleus
27.10 Cleavage produces a ball of cells from the zygote
 Cleavage is a rapid series of cell
divisions
– More cells
– Embryo does not get larger
– Thus new cells are smaller in size
Copyright © 2009 Pearson Education, Inc.
Zygote
2 cells
4 cells
8 cells
Blastula
(hollow ball)
Cross section
of blastula
Many cells
(solid ball)
Blastocoel
Cleavage in a sea urchin
27.11 Gastrulation produces a three-layered embryo
 Gastrulation
– Cells migrate
– The basic body plan of three layers is established
– Ectoderm outside—becomes skin and nervous
systems
– Endoderm inside—becomes digestive tract
– Mesoderm in middle—muscle and bone
– A rudimentary digestive cavity forms
Copyright © 2009 Pearson Education, Inc.
Blastula
(end of cleavage)
Animal pole
Blastocoel
Vegetal pole
Gastrulation
(cell migration)
Blastocoel
shrinking
Formation of a
simple digestive
cavity
Blastopore
Gastrula
(end of gastrulation)
Simple
digestive
cavity
Ectoderm
Mesoderm
Endoderm
Development of the frog gastrula
You should now be able to
1. Explain how fertility drugs have affected multiple births in the United States
2. 2. Compare the types of asexual and sexual reproduction
3. Describe the structures and functions of the male and female human reproductive
tracts
4.
5.
6.
7.
Describe
Describe
Describe
Describe
and compare spermatogenesis and oogenesis
the events of the menstrual cycle
the nature of the most common STDs
the most common forms of birth control
8. Relate the structure of sperm to its roles in fertilization
9. Describe the processes of cleavage and gastrulation
10. Describe the functions of the four extraembryonic membranes
11 Describe the main changes that occur during each trimester of human
development
12. Describe the most common reproductive technologies
Copyright © 2009 Pearson Education, Inc.
‫‪Reproduction‬‬
‫تعــريف المصطـــلح‬
‫المصطلــــــــح‬
‫‪Angiosperms‬‬
‫كاسيات البذور‬
‫‪Sporophyte :The Diploid Generation.‬‬
‫النابت البوغي ‪:‬الجيل ثنائي العدد الكروموزومي‪.‬‬
‫‪Gametophyte: The Haploid Generation.‬‬
‫النابت الجاميطي ‪:‬الجيل أحادي العدد الكروموزومي‪.‬‬
‫‪Pollen Grain: The Male Gametophyte.‬‬
‫حبه لقاح ‪:‬النابت الجاميطي المذكر‪.‬‬
‫‪Embryo Sac: The Female Gametophyte.‬‬
‫الكيس الجنيني‪ :‬النابت الجاميطي األنثوي‪.‬‬
‫‪Endosperm: Central Cell Within The‬‬
‫اإلندوسبيرم ‪:‬خلية واحدة مركزية داخل الكيس الجنيني‬
‫‪Embryo Sac Has Two Nuclei.‬‬
‫لها نواتان‪.‬‬
‫‪Pollination :Transfer Of Pollen From Anther‬‬
‫عملية التلقيح‪ :‬نقل حبوب اللقاح من ال ُمتك إلى الميسم‪.‬‬
‫‪To Stigma.‬‬
‫‪Double Fertilization: One Sperm Fertilizes‬‬
‫االخصاب المزدوج‪ :‬تقوم إحدى الخليتين المنويتين‬
‫‪The Egg To Produce A Zygote, The Other‬‬
‫بتخصيب البيضة إلنتاج الالقحة‪ ,‬و تقوم األخرى باالندماج‬
‫‪Fuses With The Central Cell Nuclei To‬‬
‫مع النواة الخلية المركزية لتنتج نسيج اإلندوسبيرم ثالثي‬
‫‪Produce 3n Endosperm.‬‬
‫العدد الكروموزومي )‪.(3n‬‬
‫‪Seed Dormancy: Embryo Growth And‬‬
‫كمون البذرة‪ :‬توقف نمو و تكوين الجنين‪.‬‬
‫‪Development Are Suspended.‬‬
‫‪Two Cotyledons = Eudicot Seeds‬‬
‫فلقتان‬
‫‪Single Cotyledon = Monocot Seeds‬‬
‫فلقة واحدة‬
Reproduction
‫المصطلــــــــح‬
‫تعــريف المصطـــلح‬
Fruit: Developed Ovary.
.‫ مبيض مكتمل النمو‬:‫الثمرة‬
Germination
‫اإلنبات‬
Asexual Reproduction: One Parent
. ً ‫ ينتج أحد الوالدين ذرية متماثلة وراثيا‬:‫التكاثر الالجنسي‬
Produces Genetically Identical Offspring.
Hermaphroditism: One Individual With
. ‫ فرد واحد بأجهزة تكاثر ذكرية وأنثوية‬:‫الخنوثة‬
Male And Female Reproductive Systems.
External Fertilization: Eggs And Sperm Are ‫ يتم إطالق البيض والحيوانات المنوية‬:‫اإلخصاب الخارجي‬
Discharged Near Each Other.
.‫بالقرب من بعضها البعض‬
Internal Fertilization: Sperm Is Deposited
‫ يتم إيداع الحيوانات المنوية في أو‬:‫اإلخصاب الداخلي‬
In Or Near The Female Reproductive Tract.
. ‫قريبا ً من القناة التناسلية لألنثي‬
Gonads: Where Gametes Are Produced.
.‫ حيث يتم انتاج الجاميطات‬:‫المناسل‬
Ovaries: Contain Follicles That Nurture
‫ تحتوي على حويصالت والتي تقوم بــ تغذية‬:‫المبايض‬
Eggs And Produce Sex Hormones.
.‫البيض وانتاج هرمونات الجنس‬
Testes (Singular Testis): Produce Sperm And
‫ تنتج الحيوانات المنوية‬:)‫الخصي (مفردها خصية‬
Male Hormones.
. ‫هرمونات الذكورة‬
Epididymis: Stores Sperm As They Develop
.‫ يتم فيه تخزين الحيوانات المنوية وإنضاجها‬:‫البربخ‬
Further
Reproduction
‫المصطلــــــــح‬
Spermatogenesis: Formation Of Sperms.
Oogenesis: Formation Of Ovum.
Menstrual Cycle
Menstruation
Corpus Luteum
Endometrium
Cleavage: Rapid Series Of Cell Divisions.
Gastrulation: Cells Migrate And Basic Body
Plan Of Three Layers Is Established.
‫تعــريف المصطـــلح‬
‫عملية تكوين الحيوانات المنوية‬
‫عملية تكوين البيض‬
‫الدورة الشهرية‬
‫الحيض‬
‫الجسم األصفر‬
‫بطانة الرحم‬
.‫ هو سلسلة سريعة من االنقسامات الخلوية‬:‫التفلج‬
‫ هجرة الخاليا و يتم تأسيس الخطة األساسية‬:‫التبطن‬
. ‫للجسم ذو الثالث طبقات‬