reproduction or at least the parts that are tested…

Reproduction

Or at least the parts that are tested…

First: What is the difference between Asexual Reproduction and Sexual

Reproduction?• When you put “a-” in front of a word it usually

means “without”• “Asexual reproduction” means reproduction

without sex.

• When you put “a-” in front of a word it usually means “without”

• “Asexual reproduction” means reproduction without sex.

Sexual Reproduction= 2 parents Asexual Reproduction= 1 parent




Gametes from the two parents are combined to form offspring that are different from each other AND their parents





The single parent can usually only produce clones of itself…



The single parent can usually only produce clones of itself…

Provides Genetic Diversity and greater survivability for

the species

Usually Faster, and 100% of the genes of an individual

are passed on


Provides Genetic Diversity and greater survivability for

the species

Faster, and 100% of the genes of an individual are

passed on

ALL organisms

Yes, I said ALL! can do this

As you know, there are animals that can’t do this

What is a Gamete?

• Most of the cells of a Human being has 46 chromosomes, and are called Diploid.

• Human Gametes are cells that have only 23 chromosomes, and are called Haploid

Have you figured it out yet?

What is a Gamete?

• Most of the cells of a Human being has 46 chromosomes, and are called Diploid.

• Human Gametes are cells that have only 23 chromosomes, and are called Haploid


Sex Cells

What is a Gamete?• Most of the cells of a Human being has 46

chromosomes, and are called Diploid.• Human Gametes are cells that have only 23

chromosomes, and are called Haploid


Sex CellsAKA: Eggs and Sperm

Are animals the only ones with Gametes?

Are animals the only ones with Gametes?Of course NOT.

• Plants and fungi have their own forms of eggs and sperm, some of them spend most of their lives AS “eggs” and “sperm”

• Protists are so weird don’t be surprised about anything that they can do.

• Bacteria are so plentiful and variable that they can do almost anything. They have ways of reproducing that we can barely imagine…

But you DO need to know about plants…

Flowers=AngiospermsFlowers Fruits

Cones= Gymnosperms

BTW: Pollen IS Sperm

So where are human Gametes made?

• Gametes are made during meiosis (more on that in February…)

• Eggs cells are made in the _______• Sperm cells are made in the ________

So where are human Gametes made?

• Gametes are made during meiosis (more in that in February…)

• Eggs cells are made in the _______• Sperm cells are made in the ________

Ovaries!

Testes!

Let’s follow the sperm first…

Where are sperm made?

Where are sperm Stored?

Which of the following makes the fluid that the sperm swim in (semen)?

What is the tube that sperm travel through on their way to the penis?

What is the tube that sperm and urine travel through on their way out of the body?

The Female

Here’s another view…

So what’s going on in there?

Every little girl is born with about 40,000 immature eggs in two ovaries. They begin to die off and she usually has only a couple of thousand by the time she starts puberty. Once a month until menopause, her ovaries will pick one of the eggs to grow into maturity. When it is ready the egg is released—called ovulation. The part left behind—the corpus luteum—then releases chemical signals that regulate the menstrual cycle.

On the male side…Sperm are made fresh every day starting at puberty—often till death. They are stored in the Epididymis for about 4-5 days. If they aren’t “used” they are broken down and reabsorbed back into the body.

So what does that mean for you?

• The part of you that came from your dad is probably no more than a couple of days older than you.

• The part of you that came from your mom is older than her.

Eggs vs. Sperm

• Scientists decide whether an organism is a male or a female by looking at who makes the eggs.

• How do you know its an egg?

Eggs vs. Sperm

• Scientists decide whether an organism is a male or a female by looking at who makes the eggs.

• How do you know its an egg?–The larger gamete

• The larger the gamete, the more “expensive” it is to make, so there are less of them.

• Generally the parent that puts more effort into its offspring has fewer of them.

• This parent is usually called the “female”

So after ovulation the egg leaves the ovary and will be gently picked up by the Fimbriae and begin its passage down the

fallopian tubes (aka the oviduct).

http://www.youtube.com/watch?v=nLmg4wSHdxQ

Fertilization happens in the Fallopian tubes (oviduct). Sperm can live for a

few days in the fallopian tubes waiting for an egg to show up.

http://www.youtube.com/watch?v=BFrVmDgh4v4

Once the Egg is fertilized it is called a Zygote and it starts to divide. When it

becomes a hallow ball of cells it is called a blastocyst (or blastula).

http://www.youtube.com/watch?v=fUpc93T12bk

The blastula implants into the endometrial layer of the uterus—this begins pregnancy. Then the blastula starts to fold inward and the cells start to differentiate and form the

three germ layers of the new organism.

http://www.youtube.com/watch?v=UgT5rUQ9EmQ

At first the Embryo feeds off of nutrients stored in the yolk sac as the placenta

develops. Eventually it will live completely off of the nutrients provided by the

placenta from the mother’s blood. It is called a Fetus at the end of the eighth

week.

http://youtube.com/watch?v=_2MFFzldkYQ

Highlights of Fetal development1st trimester

• 5 weeks: heart starts to beat• 6 weeks: arm and leg buds start to appear• 8 weeks: fingers, toes, nose, and upper lip• 9 weeks: eyes develop, eye lids are still fused,

tail gone• 10 weeks: many organs start to function,

finger and toe nails start to grow

• 14 weeks: facial expressions, maybe thumb sucking• 15 weeks: can sense light but eyes are still closed• 16 weeks: sex can be determined by ultrasound• 18 weeks: mother may begin to feel movement• 19 weeks: baby can hear• 24 weeks: taste buds develop, hair may be growing• 27 weeks: practicing breathing

Highlights of Fetal development2nd trimester

Highlights of Fetal development3rd trimester

• 28 weeks: dreaming? Eyelashes ready, eyesight improving, growing fast, lungs not ready yet

• 34 weeks: almost ready to be born but would spend a couple of days in the neonatal unit

• 37 weeks: considered “done”• 40 weeks: considered “due”• 40+ weeks: considered “overdue” or “well done”– Mother is considered “cranky”

During labor the muscular uterine walls contract—getting stronger and stronger

—forcing the baby downwards. The Cervix gets softer, shortens, and widens

to 10 cm. After the baby is born the placenta detaches itself and follows.

http://www.youtube.com/watch?v=BgZ5z6RB06c

reproduction or at least the parts that are tested…

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