Fertilization & Development
Homework: Read pgs 67-68 in RB and answer questions 22-31 on loose leaf paper.
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https://www.youtube.com/watch?v=_5OvgQW6FG4
Types of Fertilization
1. External: gametes fuse outside the body of the female Occurs in animals that breed in the water (most
invertebrates- Fish/amphibian) The two parents release their eggs into the water, and
the sperm fertilizes the eggs.
2. Internal – gametes fuse inside the body of a female
Fertilization occurs inside the female body where it is moist
Occurs mostly in animals that reproduce on land and some aquatic animals like sharks, reptiles, and mammals
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COMPARISONCOMPARISON
PROS Large numbers of eggs
and sperm are released to increase chances of survival.
Gametes released at the same time
CONS Sperm may not find the eggs. Predators may find and eat
eggs or small offspring. Changes in temperature or
oxygen content of the water may cause death.
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Fewer eggs need to be released.
Hormones and “mating signals” trigger the release of the eggs and sperm. Ex. Singing, special feathers, and pheromones.
Mating must take place within ~ 24 hours for fertilization to occur
EXTERNAL
INTERNAL
A. When sperm penetrates egg
1. Sperm releases special enzymes to do this
2. Forms a ZYGOTE
3. Recombination occurs:
a. Combining of genetic info from both parents
(n=23) (n=23) (2n=46)
Sperm + egg = zygote
C. Occurs in the oviduct (fallopian tube)
FERTILIZATION
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D. Multiple births:
fraternal twins- 2 eggs identical twins- one egg
that splits in two, always the same
Conjoined (Siamese) twins are identical twins whose bodies
are joined in utero.
Abby & Brittany Hensel
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Occurs in the oviduct (fallopian tube) Zygote begins a series of mitotic divisions (cleavage) to undergo differentiation Division process is rapid - no increase in size, just the number of cells:
1 cell→ 2 cells→ 4→ 8→ 16→32→64→ 128 …etc
Implantation of zygote in uterus occurs around day 7
Early Development- The First WeekEarly Development- The First Week
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EMBRYONIC DEVELOPMENT
Period of the zygote (silent video) http://www.bing.com/videos/search?q=Gastrulation+Animation&Form=VQFRVP#view=detail&mid=634F58C4C7A9487B3990634F58C4C7A9487B3990Follicle Development http://www.bing.com/videos/search?q=Ovarian+Cycle+Animation&Form=VQFRVP&adlt=strict&mid=59F979C28F731BF7FD6D59F979C28F731BF7FD6D%20-%20view=detail&mid=59F979C28F731BF7FD6D59F979C28F731BF7FD6D#view=detail&mid=AF57AA0A9AB206C6F4A4AF57AA0A9AB206C6F4A4
Embryonic Layers and FunctionsGASTRULATION
Cells in zygote form into 3 distinct layers
The cells within each layer The cells within each layer DIFFERENTIATE DIFFERENTIATE to formto form specialized cellsspecialized cells (muscle, liver, heart, etc) then tissue and (muscle, liver, heart, etc) then tissue and organs. organs. This is caused by This is caused by gene activationgene activation which can be which can be
influenced by the environment.influenced by the environment.
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EctodermEctoderm
• skin and nervous system
EndodermEndoderm• lining of
digestive and Respiratory
tract (body organs)
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MesodermMesoderm• Muscular,
circulatory skeletal, excretory and reproduction systems
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These developing cells are now called an embryonic stems cells and can be used as for medical research and application
http://www.brainpop.com/science/cellularlifeandgenetics/stemcells/
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HUMAN FETAL DEVELOPMENT
1. Placenta – Develops at 3 weeks Placenta is a fetal organ Connects mother and fetus
Food, gases and wastes DIFFUSE across blood vessels
watch
2. Umbilical cord- rope-like structure that connects the fetus to the placenta
3. Amnion- membrane surrounding the fetus
4. Amniotic fluid – fills the amnion, protects the fetus, and absorbs shock
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Most critical time of development is the 1st trimester when organs are developing
Harmful environmental risk factors include drugs, rugs, alcoholalcohol tobaccotobacco medicinesmedicines poor dietpoor diet, , toxic substancestoxic substances infections infections
This can halt development or cause major developmental issues
Not taking care can result in miscarriage or can severely damage embryo/fetus
First and Second Trimester Dangers!!!!
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8 weeks = FETUS
Umbilical cord forms at 3 months
Body systems become more specialized
Fetus becomes bigger
BirthBirth (36 weeks (36 weeks)
Later Development
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The end of the journey!
And you think 9 months of
Biology is hard!
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REPRODUCTIVE TECHNOLOGYIn vitro Fertilization Process – assisted reproduction
Simulation http://www.sumanasinc.com/webcontent/animations/content/invitrofertilization.html
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Directions: READ your review book pageS 71-72. Fill out the blank columns for each of the 4 technologies listed.
Technology Purpose
Agriculture 1.
2.
Ecology 1.
2.
Health Care 1.
2.
3.
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Directions: READ your review book pageS 71-72. Fill out the blank columns for each of the 4 technologies listed.
Technology Purpose
Agriculture
GMO’s –genetically modified organisms
1. Alter plants so they are resistant
to insects, frost etc. 2. Artificial insemination of farm
animals allows desired traits
Ecology
Health Care
2015 Reproduction -SMP
Directions: READ your review book pageS 71-72. Fill out the blank columns for each of the 4 technologies listed.
Technology Purpose
AgricultureGMO’s –genetically
modified organisms
1. Alter plants so they are resistant
to insects, frost etc. 2. Artificial insemination of farm
animals allows desired traits
Ecology 1. Build up of endangered populations 2. Use of hormones to regulate pest populations instead of harmful chemicals
Health Care
Directions: READ your review book pageS 71-72. Fill out the blank columns for each of the 4 technologies listed.
Technology Purpose
AgricultureGMO’s –genetically
modified organisms
1. Alter plants so they are resistant
to insects, frost etc. 2. Artificial insemination of farm
animals allows desired traits
Ecology 1. Build up of endangered populations 2. Use of hormones to regulate pest populations instead of harmful chemicals
Health Care 1. Hormone therapy Future of Infertility Treatment | Watch the video - Yahoo Finance
2. In Vitro Fertilization 3. Ultrasounds Video: Fetal ultrasound - Mayo Clinic
Answers for RB questions 32-52, pg 72-73
32) 2
33) 3
34) 2
35) 1
36) 1
37) 1
38) 3
39) 2
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49) Sperm nucleus contains half the chromosomes needed to form a normal frog
50) hormones
51) An ovary
52) 2
40) 2
41) 3
42) 3
43) 2
44) 3
45) 1
46) 4
47) 1
48) 1
Practice ANSWERS from notes:1)C2)B3)A4)B5)B6)A7)A8)D9)D10)C11)B12)a) placenta b) ie. Drugs, alcohol (see pg 4 of notes for other responses) – FAS (fetal alcohol syndrome) or low birthweight or brain/organ damage13)Interfere with development or cause low birthweight or FAS or death to fetus14)A15)C
Male Sexual DevelopmentTestosterone is the male reproductive hormoneSecreted in small amounts until puberty
Puberty begins when:Hypothalamus Pituitary increased
FSH and LH GONADS (TESTES)GONADS TESTOSTERONETestosterone produces male 2ndary sex
characteristics Ex. body hair, muscle development, deep
voice
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Male Reproductive PartsA. Testes:
Male reproductive gland Sperm and testosterone produced
B. Scrotum: Protective sac around testes Keeps testes cool (this keeps the
sperm at an optimum temperature for development
C. Epididymus: Stores sperm while they mature
D. Vas Deferens: Tube that carries sperm from
epididymis to urethra
Diagram of Testicle
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Male Reproductive PartsE. Prostate gland -- the largest of several glands which add lubricating and other fluids to the sperm
F. Urethra: tube through the penis
carrying sperm to the outside of the body
G. Other glands work together to produce seminal fluid.
Combination of sperm and seminal fluid = semen
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H. Penis- adaptation for internal fertilization of the female
Semen travels from testes →vas deferens→ urethra→ penis → outside of the body through ejaculation (uncontrolled muscle contractions)
Female Sexual Development
A. Estrogen is the female reproductive hormone
B. Puberty begins when:Hypothalamus Pituitary increased FSH
AND LH GONADS (OVARIES)GONADS Estrogen and progesterone
C. Estrogen produces female 2ndary sex characteristics
(broadening of pelvis, breast development, and are involved in the menstrual cycle and pregnancy).
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Female Reproductive PartsA. Ovaries:
Female Reproductive Gland Egg (ova) produced here Also contain follicles:
Place where eggs mature
B. Fallopian tubes (Oviduct): Tubes that carry an egg from
ovary to uterus Place of fertilization Egg Travel: From the
ovaries → fallopian tubes/oviducts → uterus
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C. Uterus:• Mostly muscle• implantation and
development of the embryo and fetus before birth occurs here
D. Vagina • Vagina (or birth canal)
entry point for sperm from the male and exit tube for the baby when it is born
Your turn
COMPLETE QUESTIONS ON: pages 3-4 of your notesPage 8 (use the diagram given)
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Answers for pages 3-4
1) B
2) A
3) A
4)D
5)C
6)B
7)C
8)D
9)C
10)A
11)D
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12) ADD LUBRICATION/NUTRIENTS FOR THE SPERM TO SWIM/TRAVEL IN
13) B
14) B
15) ESTROGEN OR PROGESTERONE OR FSH OR LH
16) D
17) A
The HORMONES-& Cycles
• Uses a negative feedback mechanism to maintain homeostasis
• Permanent cessation of the cycle is called Menopause
Add this to notes
The HormonesThe HormonesA. Secreted by the Pituitary gland:
FSH (Follicle Stimulating Hormone)Stimulates follicle to cause egg to mature
LH (Luteinizing Hormone)Causes release of mature ovum
(ovulation)Prepares uterus for implantation of
fertilized egg
B. Secreted by Ovaries: Estrogen
• Causes uterine lining to thicken Progesterone:
Works with estrogen to finish uterine lining thickening2015 Reproduction -SMP
Female Reproductive Cycle
Female Reproductive Cycle Video: 5:00 min
Menstruation Cycle of Female Reproductive Systemhttp://www.bing.com/videos/search?q=Ovarian+Cycle+Animation&Form=VQFRVP&adlt=strict&mid=59F979C28F731BF7FD6D59F979C28F731BF7FD6D#view=detail&mid=59F979C28F731BF7FD6D59F979C28F731BF7FD6D
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The CyclesThe Cycles1. Ovarian Cycle:
Occurs over 28 days in the ovaries
Process during which an ovum matures in a follicle and is released during ovulation
After ovulation, a corpus luteum (yellow body) is left behind
Ovarian Cycle (1:17) http://www.bing.com/videos/search?q=Ovarian+Cycle+Animation&Form=VQFRVP&adlt=strict#view=detail&mid=59F979C28F731BF7FD6D59F979C28F731BF7FD6D
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2. Menstrual (Uterine) Cycle:Occurs over 28 days
Process during which uterine lining is preparing for fertilized ovum
If fertilization occurs, this cycle stops until after birth
If not fertilized, lining sheds (menstruation!) and cycle begins again
THESE TWO CYCLES ARE GOING AT THE SAME TIME!!!!!!!!!!!
I REPEAT: THESE TWO CYCLES ARE GOING AT THE SAME TIME!!!!!!!!!!!
The Beginning to the end: The Beginning to the end: Phase 1-Menstruation• Occurs if egg is not
fertilized• Days 1- 5 • Corpus luteum
(yellow body) breaks down• This causes drop in
estrogen and progesterone
• Uterine lining sheds• FSH increases during
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Phase 2: Follicular PhaseDays 5 –13Low estrogen = FSH to be releasedThis stimulates growth of follicleEgg begins to
matureFollicle matures causing estrogen levels upUterine lining
begins to thicken again 2015 Reproduction -SMP
Phase 3: Ovulation http://www.bing.com/videos/search?q=Ovarian+Cycle+Animation&Form=VQFRVP&adlt=strict#view=detail&mid=59F979C28F731BF7FD6D59F979C28F731BF7FD6DDays 13-15Sudden rush of FSHMajor SPIKE of LHThis causes follicle
to break and release egg into fallopian tube
FERTILIZATION MOST LIKELY TO OCCUR AT END OF OVULATION!
Phase 4: Luteal PhaseDays 15-28LH and FSH levels crashCorpus luteum forms from broken follicleCorpus luteum secretes estrogen and progesterone This thickens uterine
lining to prepare for egg
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