Transcript Objective: Do Now: You will be able to draw

Objective: You will be able to draw
the early stages of development.
Do Now:
• Read “Fertilization” on p. 1016
• Define fertilization
• Define Zygote
Fertilization
• Meiosis creates sex cells with a monoploid
number of chromosomes
• When a sperm and an egg unite it restores
the diploid number of chromosomes
• The new cell that is formed is called a
zygote
Egg Cell
Sperm Cell
n
n
Fertilization
2n
Zygote
Cleavage
• The first few divisions after fertilization are
called cleavage
• Is the cell division done by mitosis or
meiosis?
• Cleavage ends up creating a hollow ball of
cells called the blastula
Figure 47.6x Sea urchin development, from single cell to larva
Figure 47.0 Human embryo
Figure 46.18 Human fetal development
Activity
• We will be viewing the stages of cleavage
in an animal under the microscope.
• Begin viewing the slide under the
microscope
• You will need to find the following stages:
-Zygote
-morula
-Two cell
-blastula
-Four cell
-gastrula
• For each stage draw what you see in your
notebook
Objective: You will be able to identify
and give the function of the parts of an egg.
Fertilization
• External fertilization is when the egg and
sperm unite outside the female
– Ex. Fish and frogs
• Internal fertilization is when the egg and
sperm unite inside the female
– Ex. Reptiles, birds and mammals
Development
• All animals need to grow in water
otherwise they will dry out
• External fertilization happens in the water
• Mammals have water environment inside
the female
• Reptiles and birds have internal
fertilization but lay eggs
– The egg contains the watery environemnt
What came first the chicken or the
egg?
Egg parts
• Amnion-
Fluid filled and surrounds the embryo
• Allantois-
Stores the waste produced by the embryo
• Yolk Sac-
Stores nutrient-rich food
• Chorion-
Regulates O2 going to embryo and CO2
leaving embryo
Figure 39–12 The Male
Reproductive System
Section 39-3
Figure 46.8 Reproductive anatomy of the human male (continued)
Figure 39–14 The Female
Reproductive System
Section 39-3
Figure 46.9 Reproductive anatomy of the human female (continued)
Figure 46.16 Formation of the zygote and early postfertilization events
Menstrual Cycle
• Occurs in women at the onset of puberty
• Refers to the cycle in which an egg is
released and the uterus is prepared for
pregnancy
Figure 46.13b Oogenesis
Concepts
• Involves three glands:
– Hypothalamus
– Pituitary
– Ovaries
• Involves many hormones including:
– Releasing hormone
– FSH and LH
– Estrogen
The phases
• Follicular phase- Involves the thickening of the
uterus by estrogen
– Makes egg grow in follicle
• Ovulation- Is the release of the egg from the ovary
– Caused by LH
• Luteal phase- Is the creation of the corpus luteum
which will maintain the pregnancy
– Caused by LH
• Menstruation-
Shedding of the uterus if
pregnancy does not occur
Sex Hormones
• Testosterone
– Cause the male secondary sex characteristics
• Estrogen
– Cause the female secondary sex
characteristics
Figure 38.2 Review of an idealized flower
Pistil
Objective: You will be able to identify
and give the function of the parts of a flower.
Do Now:
• Read pages 612 and 613
• For each part of the flower, write its
function
• This will take you a few minutes
Male parts
• Male part is called the stamen
• The stamen consist of the anther and
filament
• Anther
– Carries out meiosis to make pollen
– Sperm cells are inside the pollen
• Filament
– Holds the anther into the air
Female parts
• Female part is called the pistil
• The pistil is made of the stigma, style and
ovary
• Stigma is sticky to capture the pollen
• Style is a passageway to the ovary
• Ovary
– Carries out meiosis to make eggs
– The eggs are found within ovules
Objective: You will be able to describe
the events of pollination and fertilization.
Do Now:
• Read page 616
• What two things form from fertilization?
Figure 38.5 Pollen grains have tough, ornate, and distinctive walls
Pollination
• Pollination is the transfer of the pollen from
the anther to the stigma
• If the pollen lands on a flower on the
SAME plant it is called self-pollination
– If it lands on a different individual then it is
called cross-pollination
• Pollinators are used to move the pollen
Figure 38.3d1 Pollination modes
Figure 38.1 Simplified overview of angiosperm life cycle
Fertilization
• Fertilization occurs within the ovule
• There are actually two sperm cells
• The first will fertilize the egg and form a
zygote
– This zygote will undergo cleavage to from
an embryo
Fertilization
• The second sperm will fertilize a 2n cell
and form a 3n cell called the endosperm
– The endosperm is the food source for the
embryo
• This concept of two fertilizations is
called double fertilization
• It is unique to flowering plants.
After Fertilization
• The ovule itself will harden and become a
seed
• The ovary itself will change and become a
fruit
– The fruit is used for seed dispersal
Figure 38.12 Development of a pea fruit (pod)
Objective: You will be able to identify
and describe the parts of a seed.
Do Now:
• Read page 618
• Give examples of fruits that everyone
thinks are vegetables.
Figure 38.11 Seed structure
Seed Structure
• The embryo consists of the hypocotyl
and the epicotyl
– Hypocotyl becomes the root
– Epicotyl becomes the leaves and upper
part of stem
• Cotyledon is used as a food source
• The seed coat protects the seed
Seed germination
• Once proper conditions are met, the seed
will start to germinate.
• Seed germination depends on water,
oxygen and temperature
• Why not light?