Reproduction & Development

Asexual Reproduction

Defined: only 1 parent, offspring are genetically identical to the parent & each other

Types: • Binary fission: cell undergoes mitosis example: ameoba, paramecium, bacteria • Budding: mitosis with unequal division of

cytoplasm example: hydra • Sporulation: spores are scattered & grow into new

identical organisms example: mushrooms • Regeneration: new organism produced from the

severed parts of a single organism example: planaria worm, starfish

Asexual Reproduction

Binary fissionBudding

Sporulation

Regeneration

Sexual Reproduction

• 2 parents • Each parent contributes half the genetic information

to the offspring • Offspring are genetically different from the parents

and each other (unless they are identical twins)

Fertilization & Development

A. Terms 1. Fertilization: process of sperm joining an egg 2. Development: series of events that give rise to

a fully grown organism 3. Zygote: formed by the union of gametes (egg

& sperm), 1st stage of development after fertilization, contains a complete set of DNA for the offspring

Types of Fertilization & Development

B. External Fertilization- External Development: example: most fish C. Internal Fertilization-External Development: example: birds & some reptiles D. External Fertilization-Internal Development:

example: species of fish that carries developing eggs in their mouth • Internal Fertilization-Internal Development: example: humans & most mammals

Human Reproductive System

A. Reproductive Glands: produce gametes and secrete sex hormones

female: ovaries male: testes B. Sexual Development:

1st 6 weeks: male & female embryos are identical

7th week: ovaries & testes form

40 weeks: Birth

Puberty: Reproductive organs are fully developed

Male Reproductive System

Hormones & their function:

Hormone FunctionFSH

(follicle stimulating hormone)

Stimulates cells in testes to produce testosterone

LH (luteinizing hormone)

Same as FSH

Testosterone Stimulates sperm development & secondary

sex characteristics

Main Structures & their Function

• Testes-produce sperm • Epididymis-stores sperm until fully

mature • Vas deferens- connects to urethra

(sperm move into it from the epididymis)

• Urethra-tube leading outside the body through the penis

• Penis-male reproductive organ

Male Reproductive System

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Female Reproductive System

Hormones & their function:

Hormone FunctionFSH Stimulates ovaries to produce estrogen;

causes follicle to matureLH Causes follicle to mature

Estrogen Causes uterine lining to thicken; stimulates development of secondary sex characteristics

Progesterone Adds finishing touches to the uterine lining

Main Female Structures

• Ovaries-produce eggs & secrete estrogen

• Fallopian Tubes- carry eggs to uterus • Uterus- receives & protects fertilized

egg • Vagina- blood, tissue & unfertilized

egg leave; birth canal

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Egg vs. Sperm Development

• Each ovary contains 400,000 immature eggs (primary follicles)-only use about 400

• Females do not produce any new eggs during her lifetime

• Males produce sperm throughout their lifetime

The Menstrual Cycle-28 day cycle (on average)

1. Follicular phase • approximately 10 days • Estrogen level is low • FSH & LH are released & cause follicle to mature • Maturing follicle causes an increase in estrogen,

causing uterine lining to thicken

Menstrual Cycle Cont.

2. Ovulation: process of releasing a mature egg from an ovary

• Approximately 3-4 days • A sudden rush of FSH & LH causes the follicle to

rupture & release a mature egg into one of the fallopian tubes

Menstrual Cycle Cont.

3. Luteal Phase: • Begins after ovulation ends • Ruptured follicle continues to release estrogen &

begins to produce progesterone • Both hormones stimulate cell growth & tissue

development in the lining of the uterus

Menstrual Cycle Cont.

4. Menstruation: • Occurs when fertilization does not • Estrogen & progesterone levels decrease • Uterine lining detaches from the uterine wall • Tissue, blood, & unfertilized egg are released

through the vagina

Human Fertilization & Development

• Even though hundreds of millions of sperm are released during each ejaculation, only about 1% will reach the upper region of each fallopian tube

A. Fertilization: occurs in the fallopian tubes B. Implantation: fertilized egg embeds itself in the

wall of the uterus C. Early Development: Zygote: fertilized egg Embryo: 1st 8 weeks of development Fetus: after 8 weeks of development

Differentiation & Specialization

• Zygotes divide by mitosis • Cells begin to differentiate (become different from

one another) to form the specialized structures of multi-cellular organisms (example: tissues & organs)

• All cells contain a complete set of genetic information; however not all cells use every part of the DNA

• Specific genes (segments of DNA) are turned on or off depending on the function of the cell.

Placenta & Umbilical Cord

A. Placenta B. Umbilical Cord C. Uterus D. Amnion(fluid inside

the amnionic sac)

A

BC

D

Stem Cells

• Nature’s Master Cells- unspecialized cells that have the ability to grow into any one of the body’s more than 200 cell types

Types of Stem Cells: • Embryonic Stem Cells: can grow into any one of

the body’s more than 200 cell types Drawback: must be extracted from embryos • Adult Stem Cells: exist in many major tissues

including blood, skin, & brain; can be harvested without using embryos

Drawback: can only generate a limited number of cell types & are difficult to grow in culture

Stem Cells

• Umbilical cord cells: contain stem cells that can turn into blood, bone, cartilage, heart muscle, brain and liver cells; can be harvested without using embryos

Drawback: umbilical cord is not very long and doesn’t hold enough cells to treat an adult

What can they be used for? • The basis for new treatments and even cures for

disorders ranging from Parkinson’s and heart disease to diabetes and even spinal cord injury and Alzheimer’s

Label the diagram by using the following word bank:

1. Ovary 2. Follicle 3. Egg 4. Fallopian tube/oviduct 5. Uterus 6. Cervix 7. Vagina 8. Sperm

Factors that Could Negatively Affect Pregnancy & Development

• Inadequate diet: not getting enough vitamins, minerals & nutrients

• Toxins: including alcohol (FAS), drugs (both over the counter & prescription) & tobacco (low birth weight & other complications)

• Infection: certain diseases can be passed to the unborn child & cause serious problems

example: herpes, HIV, measles, mumps

Other Factors that Affect Reproduction & Development

• Gene expression: chromosomal & gene mutations like Down Syndrome & Sickle Cell Anemia

• Hormones: incorrect amounts of specific hormones or a lack of a certain hormone

example: not enough growth hormone • Environment: environmental factors can turn

specific genes on or off; there is a direct connection between learning disabilities, ADD, ADHD, health problems, physical deformities and the environment