Notes for 4/2/18 ALL notes made by Rachel Willcutts

1. REPRODUCTION NOTES START HERE
• Instructions
• 1. Fill out the notes using the computers
• 2. Complete the exit tickets (you should be working independently)
• 3. Complete the concept map (you should be working independently)
• 4. Turn in the exit tickets and concepts maps at the end of class

2. What is the longest gestation (pregnancy)
period in the animal kingdom?

3. What is the longest gestation (pregnancy) period
in the animal kingdom?
• Elephants are pregnant for nearly TWO YEARS (600-660 days).

4. What is asexual reproduction?
• Asexual reproduction: offspring forms
______________________________.
• 4 types seen in animals:
1. Fission: parent splits into 2
offspring
2. Budding: new individual forms
from outgrowth of existing
individual
3. Fragmentation and regeneration:
Parent’s body breaks apart into
pieces (fragments) and some/all of
them develop into adults.
4. Parthenogenesis: offspring
develops from unfertilized egg.
Processing: Identify each type of asexual
reproduction in the pictures below.

5. What is asexual reproduction?
• Asexual reproduction: offspring forms
without fusion of gametes.
• 4 types seen in animals:
1. Fission: parent splits into 2
offspring
2. Budding: new individual forms
from outgrowth of existing
individual
3. Fragmentation and regeneration:
Parent’s body breaks apart into
pieces (fragments) and some/all of
them develop into adults.
4. Parthenogenesis: offspring
develops from unfertilized egg.
Processing: Identify each type of asexual
reproduction in the pictures below.

6. Asexual reproduction
Female
Sexual reproduction
Generation 1
Female
Male
Generation 4
Generation 3
Generation 2
What are the advantages of asexual reproduction?

7. Asexual reproduction
Female
Sexual reproduction
Generation 1
Female
Male
Generation 4
Generation 3
Generation 2
What are the advantages of asexual reproduction?
1. More offspring
2. Faster reproduction
3. No need to find a mate

8. What is the advantage of sexual reproduction?

9. What is the advantage of sexual reproduction?
Greater genetic diversity, meaning the population will be:
1. Better able to _______to a changing environment
2. More resistant to _________

10. What is the advantage of sexual reproduction?
Greater genetic diversity, meaning the population will be:
1. Better able to adapt to a changing environment
2. More resistant to diseases
Why would disease be a greater danger for
a genetically identical population produced
through asexual reproduction?

11. What is sexual reproduction?
• Sexual reproduction: offspring result from fusion of ________(sperm and egg).
• Some sexually reproducing species have male and female individuals.
• Others are ____________, meaning they have both male and female
reproductive organs, or can change from male to female and vice versa.
• Ex: Mollusks and worms have both male and female organs, and many
species of fish and amphibians can change from male to female and vice
versa.
What would be the
advantage of being
hermaphroditic?

12. What is sexual reproduction?
• Sexual reproduction: offspring result from fusion of gametes (sperm and egg).
• Some sexually reproducing species have male and female individuals.
• Others are ____________, meaning they have both male and female
reproductive organs, or can change from male to female and vice versa.
• Ex: Mollusks and worms have both male and female organs, and many
species of fish and amphibians can change from male to female and vice
versa.
What would be the
advantage of being
hermaphroditic?

13. What is sexual reproduction?
• Sexual reproduction: offspring result from fusion of gametes (sperm and egg).
• Some sexually reproducing species have male and female individuals.
• Others are hermaphroditic, meaning they have both male and female
reproductive organs, or can change from male to female and vice versa.
• Ex: Mollusks and worms have both male and female organs, and many
species of fish and amphibians can change from male to female and vice
versa.
What would be the
advantage of being
hermaphroditic?

14. What are the benefits of internal versus external fertilization?
• Internal fertilization occurs _______ one parent’s body, producing ______ offspring with
a ______ chance of survival.
• External fertilization occurs _______both bodies, producing ____offspring with a ______
chance of survival.

15. What are the benefits of internal versus external fertilization?
• Internal fertilization occurs inside one parent’s body, producing ______ offspring with a
______ chance of survival.
• External fertilization occurs _______both bodies, producing ____offspring with a ______
chance of survival.

16. What are the benefits of internal versus external fertilization?
• Internal fertilization occurs inside one parent’s body, producing fewer offspring with a
______ chance of survival.
• External fertilization occurs _______both bodies, producing ____offspring with a ______
chance of survival.

17. What are the benefits of internal versus external fertilization?
• Internal fertilization occurs inside one parent’s body, producing fewer offspring with a
higher chance of survival.
• External fertilization occurs _______both bodies, producing ____offspring with a ______
chance of survival.

18. What are the benefits of internal versus external fertilization?
• Internal fertilization occurs inside one parent’s body, producing fewer offspring with a
higher chance of survival.
• External fertilization occurs outside both bodies, producing ____offspring with a ______
chance of survival.

19. What are the benefits of internal versus external fertilization?
• Internal fertilization occurs inside one parent’s body, producing fewer offspring with a
higher chance of survival.
• External fertilization occurs outside both bodies, producing more offspring with a ______
chance of survival.

20. What are the benefits of internal versus external fertilization?
• Internal fertilization occurs inside one parent’s body, producing fewer offspring with a
higher chance of survival.
• External fertilization occurs outside both bodies, producing more offspring with a lower
chance of survival.

21. What are the main female reproductive organs?
• Ovaries produce gametes (eggs)
• Fallopian tubes carry gametes (and
zygotes) to the uterus
• Uterus supports a developing embryo
Processing:
1) Label the ovaries, Fallopian tubes,
and uterus in the diagram.
2) What would happen if the
Fallopian tube was severed (cut)?

22. What are the main female reproductive organs?
• Ovaries produce gametes (eggs)
• Fallopian tubes carry gametes (and
zygotes) to the uterus
• Uterus supports a developing embryo
Processing:
1) Label the ovaries, Fallopian tubes,
and uterus in the diagram.
2) What would happen if the
Fallopian tube was severed (cut)?

23. How do gametes form in the ovaries?

24. How do gametes form in the ovaries?
• ________(formation of egg) begins in female embryos, but isn’t completed until years later after puberty begins.
• Each ovary contains many ______, which contain a partially developed egg (______) surrounded by support cells.
• Once a month during the process of ________, the oocyte in one of the follicles matures into a secondary oocyte
and is released into the Fallopian tube, where fertilization can take place.
Processing: Label where
the process of ovulation
occurs.

25. How do gametes form in the ovaries?
• Oogenesis (formation of egg) begins in female embryos, but isn’t completed until years later after puberty begins.
• Each ovary contains many ______, which contain a partially developed egg (______) surrounded by support cells.
• Once a month during the process of ________, the oocyte in one of the follicles matures into a secondary oocyte
and is released into the Fallopian tube, where fertilization can take place.
Processing: Label where
the process of ovulation
occurs.

26. How do gametes form in the ovaries?
• Oogenesis (formation of egg) begins in female embryos, but isn’t completed until years later after puberty begins.
• Each ovary contains many follicles, which contain a partially developed egg (______) surrounded by support cells.
• Once a month during the process of ________, the oocyte in one of the follicles matures into a secondary oocyte
and is released into the Fallopian tube, where fertilization can take place.
Processing: Label where
the process of ovulation
occurs.

27. How do gametes form in the ovaries?
• Oogenesis (formation of egg) begins in female embryos, but isn’t completed until years later after puberty begins.
• Each ovary contains many follicles, which contain a partially developed egg (oocyte) surrounded by support cells.
• Once a month during the process of ________, the oocyte in one of the follicles matures into a secondary oocyte
and is released into the Fallopian tube, where fertilization can take place.
Processing: Label where
the process of ovulation
occurs.

28. How do gametes form in the ovaries?
• Oogenesis (formation of egg) begins in female embryos, but isn’t completed until years later after puberty begins.
• Each ovary contains many follicles, which contain a partially developed egg (oocyte) surrounded by support cells.
• Once a month during the process of ovulation, the oocyte in one of the follicles matures into a secondary oocyte
and is released into the Fallopian tube, where fertilization can take place.
Processing: Label where
the process of ovulation
occurs.

29. How do FSH and LH regulate ovulation?

30. How do FSH and LH regulate ovulation?
• ____ (follicle-stimulating
hormone) and __ (luteinizing
hormone) both cause one
follicle (containing an egg) to
grow and mature inside one
of the ovaries.
• A sharp increase in LH causes
the secondary oocyte (egg)
to be released from the ovary
(_________).

31. How do FSH and LH regulate ovulation?
• FSH (follicle-stimulating
hormone) and LH (luteinizing
hormone) both cause one
follicle (containing an egg) to
grow and mature inside one
of the ovaries.
• A sharp increase in LH causes
the secondary oocyte (egg)
to be released from the ovary
(_________).

32. How do FSH and LH regulate ovulation?
• FSH (follicle-stimulating
hormone) and LH (luteinizing
hormone) both cause one
follicle (containing an egg) to
grow and mature inside one
of the ovaries.
• A sharp increase in LH causes
the secondary oocyte (egg)
to be released from the ovary
(ovulation).

33. How do estrogen and progesterone regulate menstruation?

34. How do estrogen and progesterone regulate menstruation?
• Estradiol (a form of _______)
and ___________both cause
the endometrium (uterine
lining) to ________.
• A sharp __________in the
production both hormones
causes menstruation.

35. How do estrogen and progesterone regulate menstruation?
• Estradiol (a form of estrogen)
and progesterone both cause
the endometrium (uterine
lining) to ________.
• A sharp __________in the
production both hormones
causes menstruation.

36. How do estrogen and progesterone regulate menstruation?
• Estradiol (a form of estrogen)
and progesterone both cause
the endometrium (uterine
lining) to thicken.
• A sharp __________in the
production both hormones
causes menstruation.

37. How do estrogen and progesterone regulate menstruation?
• Estradiol (a form of estrogen)
and progesterone both cause
the endometrium (uterine
lining) to thicken.
• A sharp decrease in the
production both hormones
causes menstruation.

38. What are the main male reproductive organs?
• Testes produce gametes (sperm)
• Vas deferens carry gametes to the penis
• Penis allows sperm and urine to leave the
through the urethra
Processing:
1) Label the testes, vas deferens, and
penis in the diagram.
2) What female organs are similar to
the testes and vas deferens?
3) What would happen if the vas
deferens was severed (cut)?

39. What are the main male reproductive organs?
• Testes produce gametes (sperm)
• Vas deferens carry gametes to the penis
• Penis allows sperm and urine to leave the
through the urethra
Processing:
1) Label the testes, vas deferens, and
penis in the diagram.
2) What female organs are similar to
the testes and vas deferens?
3) What would happen if the vas
deferens was severed (cut)?

40. How do gametes form in the testes?
• Sperm form in the ________.
• _______________(sperm production)
cannot occur at the body temperatures
of mammals, so the testes descend
below the body during puberty.
• Spermatogenesis takes about 7 weeks
and happens continuously in adult
males, producing hundreds of millions
of sperm each day.

41. How do gametes form in the testes?
• Sperm form in the testes.
• _______________(sperm production)
cannot occur at the body temperatures
of mammals, so the testes descend
below the body during puberty.
• Spermatogenesis takes about 7 weeks
and happens continuously in adult
males, producing hundreds of millions
of sperm each day.

42. How do gametes form in the testes?
• Sperm form in the testes.
• Spermatogenesis (sperm production)
cannot occur at the body temperatures
of mammals, so the testes descend
below the body during puberty.
• Spermatogenesis takes about 7 weeks
and happens continuously in adult
males, producing hundreds of millions
of sperm each day.

43. How do oogenesis and spermatogenesis differ?

44. How do oogenesis and spermatogenesis differ?
Spermatogenesis
1. ______daughter cells from meiosis
become mature sperm.
2. Begins in _____________and happens
continuously.
Oogenesis
1. _________ daughter cell receives all the
cytoplasm and becomes the egg cell. The other
3 “polar bodies” degenerate and die.
2. Begins ___________, but doesn’t continue
until after puberty, once a month, one gamete
at a time.

45. How do oogenesis and spermatogenesis differ?
Spermatogenesis
1. All 4 daughter cells from meiosis
become mature sperm.
2. Begins in _____________and happens
continuously.
Oogenesis
1. _________ daughter cell receives all the
cytoplasm and becomes the egg cell. The other
3 “polar bodies” degenerate and die.
2. Begins ___________, but doesn’t continue
until after puberty, once a month, one gamete
at a time.

46. How do oogenesis and spermatogenesis differ?
Spermatogenesis
1. All 4 daughter cells from meiosis
become mature sperm.
2. Begins in adolescence and happens
continuously.
Oogenesis
1. _________ daughter cell receives all the
cytoplasm and becomes the egg cell. The other
3 “polar bodies” degenerate and die.
2. Begins ___________, but doesn’t continue
until after puberty, once a month, one gamete
at a time.

47. How do oogenesis and spermatogenesis differ?
Spermatogenesis
1. All 4 daughter cells from meiosis
become mature sperm.
2. Begins in adolescence and happens
continuously.
Oogenesis
1. Only 1 daughter cell receives all the cytoplasm
and becomes the egg cell. The other 3 “polar
bodies” degenerate and die.
2. Begins ___________, but doesn’t continue
until after puberty, once a month, one gamete
at a time.

48. How do oogenesis and spermatogenesis differ?
Spermatogenesis
1. All 4 daughter cells from meiosis
become mature sperm.
2. Begins in adolescence and happens
continuously.
Oogenesis
1. Only 1 daughter cell receives all the cytoplasm
and becomes the egg cell. The other 3 “polar
bodies” degenerate and die.
2. Begins before birth, but doesn’t continue until
after puberty, once a month, one gamete at a
time.

49. Exit Ticket
1. Identify and describe one
type of asexual
reproduction.
2. Contrast the benefits of
sexual versus asexual
reproduction.
3. Based on the chart, predict
what would happen if the
ovaries continued to
produce high amounts of
progesterone after day 20.

50. DEVELOPMENT

51. When does a fetus begin to kick?

52. When does a fetus begin to kick?
• This begins in the 2nd trimester (usually around 18 weeks).
• Other milestones:
• 5 weeks: heart starts beating
• 6 weeks: eyes, nostrils, and limb buds form
• 9 weeks: tail disappears
• 10 weeks: fingernails and toenails start to form
• 11 weeks: bones harden, and hiccups can occur
• 14 weeks: thumb-sucking begins
• 19 weeks: able to hear voices and noises
• 24 weeks: hair starts to grow
• 27 weeks: able to open and close eyes
• 28 weeks: begins dreaming

53. What happens after fertilization?

54. What happens after fertilization?
1. __________: Sperm fuses with an egg in the Fallopian tube, forming a zygote
2. _______: Zygote divides (“cleavage”) forming a blastula (hollow ball of cells)
3. __________: Embryo attaches to uterus lining (1 week after fertilization). As a result:
• Implanted embryo secretes hCG, a hormone that signals ovaries to keep producing ___________(prevents menstruation)
• ________forms – a large organ (up to 1 kg) that surrounds embryo, allowing beneficial substances (nutrients, vitamins,
oxygen, and antibodies) and harmful substances (like drugs and alcohol) to be exchanged between mother and child.
4. ____________: Blastula folds in on itself, forming the 3 tissue layers
5. _______________: Organs form (week 2 – week 8)
Which stages can you identify in this video?
https://www.youtube.com/watch?v=jsFn-
_SC2Q8
Which stages can you identify
in this diagram?

55. What happens after fertilization?
1. Fertilization: Sperm fuses with an egg in the Fallopian tube, forming a zygote
2. _______: Zygote divides (“cleavage”) forming a blastula (hollow ball of cells)
3. __________: Embryo attaches to uterus lining (1 week after fertilization). As a result:
• Implanted embryo secretes hCG, a hormone that signals ovaries to keep producing ___________(prevents menstruation)
• ________forms – a large organ (up to 1 kg) that surrounds embryo, allowing beneficial substances (nutrients, vitamins,
oxygen, and antibodies) and harmful substances (like drugs and alcohol) to be exchanged between mother and child.
4. ____________: Blastula folds in on itself, forming the 3 tissue layers
5. _______________: Organs form (week 2 – week 8)
Which stages can you identify in this video?
https://www.youtube.com/watch?v=jsFn-
_SC2Q8
Which stages can you identify
in this diagram?

56. What happens after fertilization?
1. Fertilization: Sperm fuses with an egg in the Fallopian tube, forming a zygote
2. Cleavage: Zygote divides (“cleavage”) forming a blastula (hollow ball of cells)
3. __________: Embryo attaches to uterus lining (1 week after fertilization). As a result:
• Implanted embryo secretes hCG, a hormone that signals ovaries to keep producing ___________(prevents menstruation)
• ________forms – a large organ (up to 1 kg) that surrounds embryo, allowing beneficial substances (nutrients, vitamins,
oxygen, and antibodies) and harmful substances (like drugs and alcohol) to be exchanged between mother and child.
4. ____________: Blastula folds in on itself, forming the 3 tissue layers
5. _______________: Organs form (week 2 – week 8)
Which stages can you identify in this video?
https://www.youtube.com/watch?v=jsFn-
_SC2Q8
Which stages can you identify
in this diagram?

57. What happens after fertilization?
1. Fertilization: Sperm fuses with an egg in the Fallopian tube, forming a zygote
2. Cleavage: Zygote divides (“cleavage”) forming a blastula (hollow ball of cells)
3. Implantation: Embryo attaches to uterus lining (1 week after fertilization). As a result:
• Implanted embryo secretes hCG, a hormone that signals ovaries to keep producing ___________(prevents menstruation)
• ________forms – a large organ (up to 1 kg) that surrounds embryo, allowing beneficial substances (nutrients, vitamins,
oxygen, and antibodies) and harmful substances (like drugs and alcohol) to be exchanged between mother and child.
4. ____________: Blastula folds in on itself, forming the 3 tissue layers
5. _______________: Organs form (week 2 – week 8)
Which stages can you identify in this video?
https://www.youtube.com/watch?v=jsFn-
_SC2Q8
Which stages can you identify
in this diagram?

58. What happens after fertilization?
1. Fertilization: Sperm fuses with an egg in the Fallopian tube, forming a zygote
2. Cleavage: Zygote divides (“cleavage”) forming a blastula (hollow ball of cells)
3. Implantation: Embryo attaches to uterus lining (1 week after fertilization). As a result:
• Implanted embryo secretes hCG, a hormone that signals ovaries to keep producing progesterone (prevents menstruation)
• ________forms – a large organ (up to 1 kg) that surrounds embryo, allowing beneficial substances (nutrients, vitamins,
oxygen, and antibodies) and harmful substances (like drugs and alcohol) to be exchanged between mother and child.
4. ____________: Blastula folds in on itself, forming the 3 tissue layers
5. _______________: Organs form (week 2 – week 8)
Which stages can you identify in this video?
https://www.youtube.com/watch?v=jsFn-
_SC2Q8
Which stages can you identify
in this diagram?

59. What happens after fertilization?
1. Fertilization: Sperm fuses with an egg in the Fallopian tube, forming a zygote
2. Cleavage: Zygote divides (“cleavage”) forming a blastula (hollow ball of cells)
3. Implantation: Embryo attaches to uterus lining (1 week after fertilization). As a result:
• Implanted embryo secretes hCG, a hormone that signals ovaries to keep producing progesterone (prevents menstruation)
• Placenta forms – a large organ (up to 1 kg) that surrounds embryo, allowing beneficial substances (nutrients, vitamins,
oxygen, and antibodies) and harmful substances (like drugs and alcohol) to be exchanged between mother and child.
4. ____________: Blastula folds in on itself, forming the 3 tissue layers
5. _______________: Organs form (week 2 – week 8)
Which stages can you identify in this video?
https://www.youtube.com/watch?v=jsFn-
_SC2Q8
Which stages can you identify
in this diagram?

60. What happens after fertilization?
1. Fertilization: Sperm fuses with an egg in the Fallopian tube, forming a zygote
2. Cleavage: Zygote divides (“cleavage”) forming a blastula (hollow ball of cells)
3. Implantation: Embryo attaches to uterus lining (1 week after fertilization). As a result:
• Implanted embryo secretes hCG, a hormone that signals ovaries to keep producing progesterone (prevents menstruation)
• Placenta forms – a large organ (up to 1 kg) that surrounds embryo, allowing beneficial substances (nutrients, vitamins,
oxygen, and antibodies) and harmful substances (like drugs and alcohol) to be exchanged between mother and child.
4. Gastrulation: Blastula folds in on itself, forming the 3 tissue layers
5. _______________: Organs form (week 2 – week 8)
Which stages can you identify in this video?
https://www.youtube.com/watch?v=jsFn-
_SC2Q8
Which stages can you identify
in this diagram?

61. What happens after fertilization?
1. Fertilization: Sperm fuses with an egg in the Fallopian tube, forming a zygote
2. Cleavage: Zygote divides (“cleavage”) forming a blastula (hollow ball of cells)
3. Implantation: Embryo attaches to uterus lining (1 week after fertilization). As a result:
• Implanted embryo secretes hCG, a hormone that signals ovaries to keep producing progesterone (prevents menstruation)
• Placenta forms – a large organ (up to 1 kg) that surrounds embryo, allowing beneficial substances (nutrients, vitamins,
oxygen, and antibodies) and harmful substances (like drugs and alcohol) to be exchanged between mother and child.
4. Gastrulation: Blastula folds in on itself, forming the 3 tissue layers
5. Organogenesis: Organs form (week 2 – week 8)
Which stages can you identify in this video?
https://www.youtube.com/watch?v=jsFn-
_SC2Q8
Which stages can you identify
in this diagram?

62. Question from last year: What happens if a zygote implants in the Fallopian tube?
• This results an ectopic pregnancy. (Happens
in 1-2% of pregnancies.)
• The embryo is not viable (won’t survive).
• 50% of the time, this results in a natural
miscarriage.
• If the pregnancy doesn’t miscarry naturally,
the Fallopian tube will rupture, causing severe
bleeding and possibly killing the mother.
• Ectopic pregnancies that do not miscarry on
their own are usually aborted in places where
women have access to abortion.

63. Processing:
1) Which process is shown here?
2) What is the hollow ball of the cells at the end called?
3) Which process will happen next?
(a) Fertilized egg (b) Four-cell stage (c) Early blastula (d) Later blastula

64. Figure 47.9a-5
Key Mouth
Mesenchyme
(mesoderm forms
future skeleton)
Anus
(from blastopore)
Digestive tube
(endoderm)
Ectoderm
Future ectoderm
Future mesoderm
Future endoderm
Processing:
1) Which process is shown here?
2) Which process will happen next?
3) What are the 3 tissue layers that develop here?
4) What body systems will form from each of the 3 layers?

65. What organs arise from each of the 3 tissue layers?

66. • Ectoderm  skin, central nervous system, respiratory system
• Mesoderm  bones, muscle, circulatory system, kidneys
• Endoderm  digestive tract, lungs
What organs arise from each of the 3 tissue layers?

67. (b) Neural tube formation
Neural
fold
Neural plate
Figure 47.13b-1
1) What is forming here?
2) Can you guess what this
will later develop into?

68. (b) Neural tube formation
Neural
fold
Neural plate
Neural
crest cells
Figure 47.13b-2
1) What is forming here?
2) Can you guess what this
will later develop into?

69. (b) Neural tube formation
Neural
fold
Neural plate
Neural
crest cells
Outer layer
of ectoderm
Neural
crest cells
Neural
tube
Figure 47.13b-3
1) What is forming here?
2) Can you guess what this
will later develop into?

70. What happens during organogenesis?
• During ___________, organs arise
from the 3 tissue layers.
• During early organogenesis:
• The _________, which later
becomes the CNS, arises from
the ectoderm
• The _________arises from the
mesoderm.
• The coelom (body cavity)
forms from the mesoderm.

71. What happens during organogenesis?
• During organogenesis, organs arise
from the 3 tissue layers.
• During early organogenesis:
• The _________, which later
becomes the CNS, arises from
the ectoderm
• The _________arises from the
mesoderm.
• The coelom (body cavity)
forms from the mesoderm.

72. What happens during organogenesis?
• During organogenesis, organs arise
from the 3 tissue layers.
• During early organogenesis:
• The neural tube, which later
becomes the CNS, arises from
the ectoderm
• The _________arises from the
mesoderm.
• The coelom (body cavity)
forms from the mesoderm.

73. What happens during organogenesis?
• During organogenesis, organs arise
from the 3 tissue layers.
• During early organogenesis:
• The neural tube, which later
becomes the CNS, arises from
the ectoderm
• The notochord arises from the
mesoderm.
• The coelom (body cavity)
forms from the mesoderm.

74. What happens during organogenesis?

75. What happens during organogenesis?
• During late organogenesis, many
organs begin to form, including:
• The brain
• The eyes
• The heart
• The blood vessels

76. What are cell determination and cell differentiation?

77. What are cell determination and cell differentiation?
• ____________: a cell becomes committed to a particular fate.
• ____________: a stem cell becomes a specialized cell.

78. What are cell determination and cell differentiation?
• Determination: a cell becomes committed to a particular fate.
• Differentiation: a stem cell becomes a specialized cell.

79. 1) When is the fate of the dark grey cells determined?
2) When does differentiation occur?
64-cell embryos
Blastomeres
injected with dye
Larvae
(b) Cell lineage analysis in a tunicate

80. What determines the body axes of an embryo?

81. What determines the body axes of an embryo?
• Anterior-posterior axis is determined during _________
(egg formation)
• Dorsal-ventral axis is determined at ____________

82. What determines the body axes of an embryo?
• Anterior-posterior axis is determined during oogenesis
(egg formation)
• Dorsal-ventral axis is determined at ____________

83. What determines the body axes of an embryo?
• Anterior-posterior axis is determined during oogenesis
(egg formation)
• Dorsal-ventral axis is determined at fertilization

84. How is the fate of embryonic cells determined?
1) What is happening here?
2) Are these signal molecules
(inducers) water soluble or
lipid soluble? How can you
tell?
3) What is a signal
transduction pathway?

85. How is the fate of embryonic cells determined?
• Embryonic cells remain _________ (can develop
into any cell) until the 8-cell stage.
• As cells differentiate, they help determine the
fate of nearby cells by releasing signal molecules.
This is called ________.
• Inductive signal molecules cause genes in the
target cell to be _________________, which
determines how the cell will ___________.

86. How is the fate of embryonic cells determined?
• Embryonic cells remain totipotent (can develop
into any cell) until the 8-cell stage.
• As cells differentiate, they help determine the
fate of nearby cells by releasing signal molecules.
This is called ________.
• Inductive signal molecules cause genes in the
target cell to be _________________, which
determines how the cell will ___________.

87. How is the fate of embryonic cells determined?
• Embryonic cells remain totipotent (can develop
into any cell) until the 8-cell stage.
• As cells differentiate, they help determine the
fate of nearby cells by releasing signal molecules.
This is called induction.
• Inductive signal molecules cause genes in the
target cell to be _________________, which
determines how the cell will ___________.

88. How is the fate of embryonic cells determined?
• Embryonic cells remain totipotent (can develop
into any cell) until the 8-cell stage.
• As cells differentiate, they help determine the
fate of nearby cells by releasing signal molecules.
This is called induction.
• Inductive signal molecules cause genes in the
target cell to be expressed or repressed, which
determines how the cell will ___________.

89. How is the fate of embryonic cells determined?
• Embryonic cells remain totipotent (can develop
into any cell) until the 8-cell stage.
• As cells differentiate, they help determine the
fate of nearby cells by releasing signal molecules.
This is called induction.
• Inductive signal molecules cause genes in the
target cell to be expressed or repressed, which
determines how the cell will differentiate.

90. How does induction regulate the formation of limbs?
• The cells in specific areas of a limb bud release ______________________.
• In response to inductive signal molecules:
• Certain genes in target cells are ___________________, causing the cell to ___________.
• Some target cells are stimulated to undergo _________(programmed cell death) to create
space between the digits (fingers and toes)
Which of these cells
would you expect to
undergo apoptosis?

91. How does induction regulate the formation of limbs?
• The cells in specific areas of a limb bud release signal molecules (inducers).
• In response to inductive signal molecules:
• Certain genes in target cells are ___________________, causing the cell to ___________.
• Some target cells are stimulated to undergo _________(programmed cell death) to create
space between the digits (fingers and toes)
Which of these cells
would you expect to
undergo apoptosis?

92. How does induction regulate the formation of limbs?
• The cells in specific areas of a limb bud release signal molecules (inducers).
• In response to inductive signal molecules:
• Certain genes in target cells are expressed or repressed, causing the cell to ___________.
• Some target cells are stimulated to undergo _________(programmed cell death) to create
space between the digits (fingers and toes)
Which of these cells
would you expect to
undergo apoptosis?

93. How does induction regulate the formation of limbs?
• The cells in specific areas of a limb bud release signal molecules (inducers).
• In response to inductive signal molecules:
• Certain genes in target cells are expressed or repressed, causing the cell to differentiate.
• Some target cells are stimulated to undergo _________(programmed cell death) to create
space between the digits (fingers and toes)
Which of these cells
would you expect to
undergo apoptosis?

94. How does induction regulate the formation of limbs?
• The cells in specific areas of a limb bud release signal molecules (inducers).
• In response to inductive signal molecules:
• Certain genes in target cells are expressed or repressed, causing the cell to differentiate.
• Some target cells are stimulated to undergo apoptosis (programmed cell death) to create
space between the digits (fingers and toes)
Which of these cells
would you expect to
undergo apoptosis?

95. Exit Ticket (Development)
1. Explain the role of cell signaling (induction) in embryonic development.
2. Draw (or describe in words) what happens during:
a) Fertilization
b) Cleavage
c) Implantation
d) Gastrulation
e) Organogenesis