Objective: You will be able to draw the early stages of development. Do Now: Read “Fertilization” on p. 1016 Define fertilization Define Zygote.

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

nn

Fertilization

2nZygote

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 -Two cell -Four cell -morula -blastula -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 SystemSection 39-3

Figure 46.8 Reproductive anatomy of the human male (continued)

Figure 39–14 The Female Reproductive SystemSection 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?