Final_Bio-Lectures

Ther are close to 1/2 million follicles in a woman's ovaries.

No, there are no signs of sperm in a boy's testes at the age of eight.

When puberty initially begins there are no outward signs, and it usually begins at night.

Gonadotropin is the name of the hormone produced in the brain that signals the onset of puberty.

Gonadotropin causes the cells of the testes to organize themselves into an enornous amount of tubes, where eventually the sperm will be produced.

Gonadotropins seep out of the tubes of the testes and cause these cells to produce the male sex hormone called testosterone.

Although hormone changes have begun at the age of eight, thirteen is the age at which a boy begins to change into a man.

Testosterone seeps out of the cells of the brain, soaking through dormant cells of the reproductive circuit, which transforms his brain, and gives him a drive for sex.

Yes, Natalie's brain over last five years has also been changing.

Gonadotropin brings to life Natalie's ovaries, and causes the follicles to grow and an egg inside to mature.

The female sex hormone is termed estrogen.

Yes, testosterone and estrogen have a definitive effect on your behavior!

Yes, the male reproductive circuits certainly is detrimental to the ability of a male to think properly.

Hormone levels tend to rise at night, which causes sexual arousal.

The male erection is 5-times larger than normal.

The female actually starts puberty later, but initally produces more estrogen, which has the effect of making her grow and become taller than a male of the same age, and makes her look more mature, even though she is not.

The male gets his estrogen for bone growth from transforming excess testosterone into estrogen, which happens at a slower rate than a girl. estrogen causes bone growth in both males and females.

Even though girls look more mature than boys of the same age, they are no closer to reproducing than boys are.

The female gets her testosterone from her adrenal glands, which also changes her brain circuitry and gives her a sex drive. Sex drive for both males and females is due to testosterone.

Testosterone behaviorally gives a person a sex drive and makes them more aggressive.

At high levels testosterone triggers the cells of the testes to give rise to sperm.

The follicles grows to 100-times greater size when mature.

A big testosterone surge causes your sebaceous (oil) gland to become bigger and more moist, which results in bacterial infections and what we term a pimple.

Estrogen keeps testosterone levels in-check in women.

Estrogen causes the chest, hips and posterior to draw fats out of there surrounding tissue and to be deposited in those areas, which makes a female more attractive to a male.

After a boy has created enough testosterone, it is then converted into estrogen and he gets a growth spurt. This is why his growth lags that of females.

The drawback of rapid growth for a boy is that it takes awhile for his brain to coordinate the muscles for the increased size of the limbs and he becomes a little uncoordinated.

Yes, testosterone causes the muscle to produce more fiber (which thickens them and is why they are bigger than a women's) and it cause the penis to growth in girth and length.

Testosterone in a female causes her to grow arm-pit and pubic hairs, which are breeding ground for bacteria that produces an odor that our ancestors (and some modern men) found/find sexually attractive.

Estrogen is produced by the ovarian follicle.

Gonadotropin is required for full follicle development.

When a girl does not enough estrogen levels in her blood-which  keeps seban (oil) levels down in her oil (sebaceous) gland-then her testosterone levels are relatively high an she develops pimples.

Also when the estrogen levels decline the lining of the uterus in the womb dies, which results in a period or menstruation.

In our ancestors aggression was necessary to fight for a mate.

Yes, the sex and aggression circuits of the brain are overlapped.

No, the sperm cell in the tubes of the testes is not capable of swimming. The tubes contract and force sperm into a special storage area (the epididymus) where they develop tails.

What is unique about a girls first period is that it has not been triggered by the production of a fertile egg cell. Which makes her incapable of reproducing at her first period.

The rate of sperm production at 18 years old is 1000/second! Since there are 60 seconds in an hour= 60x1000= 60,000/minute; with 60 minutes per hour 60,000 x 60= 3.6 million/hour; with 24 hours in a day is 24 x 3.6 million= 86.4 million sperm/day. (It takes 3 or 4 days on the average to give a male enough sperm to be fertile.)

The most momentous event of a full puberty for a female is the release of a mature egg from the ovary.

After the release of the egg -providing it is not fertilized- there are two weeks before the shedding of the lining of the womb.

A woman will produce an egg for 40 years. Since there are 12 months in a year that is 12 X 40= 480 total eggs in a lifetime.

No, you are not adult enough to have sex when you are reproductively mature?

Apparently, humans have such a long drawn-out puberty in order to learn the complex behavioral rules of our species before sex gets in the way!

The taxonomic characteristics of plants are: True multicellularity, cell walls with cellulose, sedentary, indeterminate growth, food stored as starch, multicellular gamete and spore chambers, retain embryos, and alternation of generation life cycle.

In the alternation of generation life cycle of plants a section of the sporophyte will undergo meiosis producing spores. The spores grow into the gametrophyte which produces the gametes.

Gametes have the capability (potential) of fusing with one another, whereas spores cannot do this, but can only grow into a gametrophyte.

The gametrophyte is always small and simple to make it possible for the sperm to swim to the egg. Which is the reason it is retained in the plant cycle.

No there is really no such thing as a gender in plants.

The three major areas of adaptations a plant must adjust to in inhabiting a dry terrestrial environment are; (1) Strengthing tissue to grow tall and resist the effects of gravity, (2) Prevent drying out, and (3) Sexually reproduce in a dry environment.

Mosses, liverworts and hornworts are examples of Non-vascular, Seedless plants.

Non-vascular seedless are small because they have no vascular tissue for strengthening and transport.

The two functions of vascular tissue are the transport of water, mineral and food, and support.

The non-vascular plants evolved 400 million years ago.

The non-vascular plants are neither well adapted structurally or repproductively to a terrestrial environment. They do not possess a cuticle or stomata.

The four main characteristics of vascular plants are: (1) True roots, stems and leaves, (2) Cuticle and stomata, (3) Sporophyte is dominant and complex, and (4) Much bigger than non-vascular plants.

Ferns, horsetails, club mosses (not a true moss), are examples of seedless vascular plants.

The ferns are structurally well adapted to an arid environment because they possess a cuticle with stomata to help regulate water loss.

Reproductively ferns are tied to a moist environment because they possess wimming sperm.

The three reproductive advances made by the seed plants over the ferns were: (1) Seeds, which allows a baby plant to wait to grow until it rains, (2) Retain the spores (no spore dispersal) and hence, the vulnerable gametrophyte is retained on the sporophyte, which is eventually wrapped up within the seed as food for the baby plant, and (3) Pollen grains, which are tailess sperm cells. The seed food is really a packaged gametophyte.

The three parts of a seed are the seed coat, food (the female gametophyte, really) and a baby plant.

A pollen grain is a tailless sperm.

Yes, all plants possess spores, but you do not notice them because the seed plants do not disperse their spores, but retain them, where they grow into very small gametophytes, either in the cones, or in the flowers.

Male cones contain pollen; female cones contain eggs and eventually the seeds. 

Pollen cones are expected to be found near the bottom of the tree help prevent self-pollination.

Pollen grains of conifers possess wings that aid in dispersal by the wind.

The two reproductive features of flowering plants that helped them out compete the conifers are the flowers and fruit (expanded ovaries).

The function of the flower is to attract pollinators.

The function of fruit is to disperse seeds.

The three vegetative parts of the plants are roots, stems and leaves. Vegetative parts are concerned with growth and maintenance of a plant.

The three reproductive parts of a plant are the flowers, fruits and seeds.

• Flower-to attract pollinators
• Fruit-to disperse seeds.
• Seeds-reproduction.

In the age of the planetwere considered into a year, plants first appeared at the begining of November.

Moving out of the water presented a serious problem of support, in order to withstand the effects of gravity.

The ancestors of plants was a green algae.

A swimming sperm keeps the mosses tied to the water.

Yes, the sperm of liverworts are mobile.

The Moss capsule contains microscopic grains of spores, which grow into new moss plants. Wind is the environmental factor that disperses the spores.

Each segment of a millipede has a spiracle (hole in the abdomen) for breathing.

The first animal hunters on the land were scorpions, while the first day-time hunters were the spiders.

Without water to transport the sperm to the egg animals had to get together.

The moss forests were only a few inches high.

No, mosses do not possess real roots, stems and leaves.

The next forests have thicker cell walls, which give them the ability to grow tall.

300 million years ago the horsetail forests were 90 feet tall (30 meters)

The tall tree ferns overcame the problem of height in sexual reproduction by continuing to produce spores, which grow into small gametophytes, where the sperm does not have a great distance to swim.

The smallness of the gametophyte makes it physically possible for the sperm to swim to the egg.

Spores of tree ferns are produced on the underside of its leaves.

Flight was the great achievement of the insects. They had the air to themselves for over 100 million years.

The sex cell producing stage of a fern would be safer if it took place in the top of the tree, but this would require some way of transferring the sex-cells from tree to tree. They could use the wind for this, or they could use insects.

The 1st kind of plants that kept the sex cell stage fixed to the tree stage were the cycads.

Pollen is contained in the male cones of cycads.

Petrified Forest of Arizona are 200 million-year-old fossils of conifers.

Yes, male and female cones are normally on the same tree.

Pollen falls out of male cones.

Conifers use the wind to transport their pollen.

Seeds fall out of female cones.

No, conifers do not need water for help in fertilization.

1/3 of the world's forests are conifers.

A Giant Sequoia Tree, name the General Sherman tree is the biggest living organism in the world. It is 112 meters (367 feet) tall with a 12 meter (40 foot) diameter.

The most effective predators on insects are the spiders.

No, the insects have stayed pretty much the same for the last 200 million years.

Flowering plants brought color to the land.