sÍntesis de primer periodo

Science - Social Studies & Math First Period 2015

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THE REPRODUCTIVE SYSTEM

The reproduction is the process by which new organisms are generated. It is the mechanism of

species continuation. There are two means of reproducing: asexual and sexual reproduction. Each

system has a specific set of structures which are used to handle certain body functions:

1. Mitosis is the division of a single nucleus into two genetically identical daughter nuclei. A

somatic, diploid cell reproduces its chromosomes and divides to form two diploid cells. This is

used in asexual reproduction to create another organism that is identical to the first.

2. Fission is a means of asexual reproduction whereby a parent separates into two or more

genetically identical individuals of about equal size.

3. Budding is a means of asexual reproduction whereby a new individual develops from an

outgrowth of a parent, splits off, and lives independently. Budding requires fission or mitosis to

take place. Many invertebrates use budding to create individuals from existing ones.

4. Fragmentation is a means of asexual reproduction whereby a single parent breaks into parts that

regenerate into whole new individuals. Starfish use fragmentation accompanied by regeneration,

the regrowth of body parts from pieces of an animal, to reproduce. Reproduction occurs if two or

more pieces of a parent body regenerate into complete adults.

5. Sporulation is asexual reproduction by the production and release of spores. Organisms such as

fungi create spores that grow directly into new individuals.

6. Vegetative reproduction is a type of asexual reproduction in plants that relies not on spores, but

on multi-cellular structures formed by the parent plant. It has long been exploited in

horticulture and agriculture, with various methods employed to multiply stocks of plants.

7. meiosis is the division of a single diploid into four haploid daughter nuclei. Meiosis and

cytokinesis produce haploid gametes from dimploid cells in the reprocuctive organs of the

parents. By first copying the cells, then splitting them into four hapoid cells, the genetic material

is divided to ensure that when two sex cells are combined in fertilization, the zygote is made up of

diploid cells.


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The male and female reproductive systems are designed to create new life. Eggs (ova) are made in

the female's ovaries, and sperm in the male's testicles. The ovaries and testicles (gonads) also make

sex hormones. Common problems of the reproductive system include infertility, sexually

transmissible infections (STIs), endometriosis, fibroids, painful periods, impotence and prostate

problems.

Functions of the Male Reproductive System

All organisms reproduce, including humans. Like other mammals, humans have a body system that

controls reproduction. It is called the reproductive system. It is the only human body system that is

very different in males and females. The male and female reproductive systems have different

organs and different functions. The male reproductive system has two main functions:

a. Producing sperm.

b. Releasing testosterone into the body.

Sperm are male gametes. When a male gamete meets a female gamete, they can form a new

organism. Sperm form when certain cells in the male reproductive system divide by meiosis. When

they grow older, males produce millions of sperm each day. Testosterone is the main sex hormone in

males. Hormones are chemicals that control many body processes. Testosterone has two major roles:

During the teen years, testosterone causes the reproductive organs to mature. It also causes other

male traits to develop. For example, it causes hair to grow on the face.

During adulthood, testosterone helps a man to produce sperm. When a hormone is released into

the body, we say it is "secreted." Testosterone is secreted by males, but it is not the only hormone

that males secrete. Males also secrete small amounts of estrogen. Even though estrogen is the main

female sex hormone, scientists think that estrogen is needed for normal sperm production in males.

Male Reproductive Organs

The penis is a cylinder-shaped organ. It contains the urethra. The urethra is a tube that carries

urine out of the body. The urethra also carries sperm out of the body.

The two testes (singular, testis) are egg-shaped organs. They produce sperm and secrete

testosterone. The testes are found inside of the scrotum. As you can see from Figure above, the

scrotum is a sac that hangs down outside the body. The scrotum also contains the epididymis.


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The epididymis is a tube that is about 6 meters (20 feet) long in adults. It is tightly coiled, so it fits

inside the scrotum. It rests on top of the testes. The epididymis is where sperm grow larger. The

epididymis also stores sperm until they leave the body.

The vas deferens is a tube that carries sperm from the epididymis to the urethra.

The prostate gland secretes a fluid that mixes with sperm to help form semen. Semen is a "milky"

liquid that carries sperm through the urethra and out of the body.

Male reproductive hormones:

Hormones are chemical messengers made by glands in the body. Androgens are the hormones that

make men male. Androgens are responsible for sexual functioning, fertility and secondary sexual

characteristics such as muscle mass, height, deep voice and body hair (including the beard). The

most important androgen is testosterone, which is manufactured in the testicles.

The sperm: The sperm is the male reproductive cell. Its role is to fertilize an egg. It contains the

mans genetic material in its head. A sperm is tadpole-shaped and around 60 microns in length

(one micron is a millionth of a meter). It has a lashing tail, which helps it to swim towards a waiting

egg. Sperm production requires a temperature around 2 C lower than that of the body, which is

why the testicles are housed in the scrotum and happens. Sperm production continues throughout a

mans life, from puberty into old age. A sperm has three main parts:

a. The head of the sperm contains the nucleus. The nucleus holds the chromosomes. Remember, in

humans, the nucleus of the sperm cell contains 23 chromosomes. The head also contains enzymes

that help the sperm break through the cell membrane of an egg. You will read more about this

process later in this chapter.

b. The mid piece of the sperm is packed with mitochondria. Mitochondria are organelles in cells that

produce energy. Sperm use the energy in the mid piece to move.

c. The tail of the sperm moves like a propeller, around and around. This pushes the sperm forward.

A sperm can travel about 30 inches per hour. This may not sound very fast, but dont forget how

small a sperm is. For its size, a sperm moves about as fast as you do when you walk briskly.


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Sperm Production:

To make sperm, cells start in the testes and end in the epididymis. It takes up to two months to

make sperm. The steps are explained below:

a. Special cells in the testes go through mitosis (cell division) to make identical copies of themselves.

b. The copies of the original cells divide by meiosis, producing cells called spermatids.

The spermatids have half the number of chromosomes as the original cell. The spermatids are

immature and cannot move on their own.

c. The spermatids move from the testes to the epididymis.

d. In the epididymis, spermatids slowly grow older and mature. They grow a tail. They also lose some

of the cytoplasm from the head.

e. When sperm are mature, they can swim. The mature sperm are stored in the epididymis until it

is time for them to leave the body.

Sperm leave the epididymis through the vas deferens. As they travel through the vas deferens, they

pass by the prostate and other glands. The sperm mix with liquids from these glands, forming

semen. The semen travels through the urethra and leaves the body through the penis. A teaspoon of

semen may contain as many as 500 million sperm!

Functions of the Female Reproductive System:

Most of the male reproductive organs are outside of the body. But female reproductive organs are

inside of the body. The male and female organs also look very different and have different jobs. Two

of the functions of the female reproductive system are similar to the functions of the male

reproductive system. The female system:

a. Produces gametes.

b. Secretes a major sex hormone, estrogen.

One function of the female reproductive system is to produce eggs. Eggs are female gametes, and

they are made in the ovaries. After puberty, females release only one egg at a time. Eggs are actually

made in the body before birth, but they do not fully develop until later in life. Another job of the

female system is to secrete estrogen. Estrogen is the main sex hormone in females. Estrogen has two

major roles:


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a. During the teen years, estrogen causes the reproductive organs to develop. It also causes other

female traits to develop. For example, it causes the breasts to grow.

b. During adulthood, estrogen is needed for a woman to release eggs. The female reproductive

system has another important function. It supports a baby as it develops before birth. It also gives

birth to the baby at the end of pregnancy.

Female Reproductive Organs

The vagina is a cylinder-shaped organ found inside of the female body. One end of the vagina

opens at the outside of the body. The other end joins with the uterus. During sexual intercourse,

sperm may be released into the vagina. The sperm move through the vagina and into the uterus.

During birth, a baby passes from the uterus and to the vagina to leave the body.

The uterus is a hollow organ with muscular walls. The part that connects the vagina with the

uterus is called the cervix. The uterus is where a baby develops until birth. The walls of the uterus

grow bigger as the baby grows. The muscular walls of the uterus push the baby out during birth.

The two ovaries are small, oval organs on either side of the uterus. Each ovary contains thousands

of eggs. The eggs do not fully develop until a female has gone through puberty. About once a month,

an egg is released by the ovary. The ovaries also secrete estrogen.

The two fallopian tubes are narrow tubes that open off from the uterus. Each tube reaches for one

of the ovaries, but the tubes are not attached to the ovaries.

Eggs and Egg Production:

When a baby girl is born, her ovaries contain all of the eggs they will ever produce. But these eggs

are not fully developed. They develop only after she starts having menstrual periods at about age 12

or 13. Just one egg develops each month. A woman will release an egg once each month until she is in

her 40s.

Eggs: Are very big cells. In fact, theyre the biggest cells in the human body. An egg is about 30 times

as wide as a sperm cell! You can even see an egg cell without a microscope. Like a sperm cell, the egg

contains a nucleus with half the number of chromosomes as other body cells. Unlike a sperm cell,

the egg contains a lot of cytoplasm, which is why it is so big. The egg also doesnt have a tail.

Egg Production: Egg production takes place in the ovaries. It takes several steps to make an egg:


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a. Before birth, special cells in the ovaries go through mitosis (cell division).

b. The daughter cells then start to divide by meiosis. But they only go through the first of the two cell

divisions of meiosis at that time. They go through the second stage of cell division after the female

goes through puberty.

c. In a mature female, an egg develops in an ovary about once a month.

Fertilization:

Occurs if a sperm enters the egg while it is passing through the Fallopian tube, the egg finally

completes meiosis. This results in two daughter cells that are different in size. The smaller cell is

called a polar body. It contains very little cytoplasm. It soon breaks down and disappears. The larger

cell is the egg. It contains most of the cytoplasm. This will develop into a child.

The Monthly Cycle: Egg production in the ovary is part of the menstrual cycle. The menstrual cycle

is a series of changes in the reproductive system of mature females that repeats every month.

Menstruation

While the egg and follicle are developing in the ovary, tissues are building up inside the uterus. The

uterus develops a thick lining covered in tiny blood vessels. This prepares the uterus to receive an

egg that could develop into a child. If a sperm does not enter an egg in the Fallopian tube, the lining

of the uterus breaks down. Blood and other tissues from the lining break off from the uterus. They

pass through the vagina and out of the body. This is called menstruation. Menstruation is also

called a menstrual period. It lasts about 4 days, on average. When the menstrual period ends, the

cycle repeats. Some people think that the average length of a menstrual period is the same as the

normal length. They assume that shorter or longer menstrual periods are not normal. In fact,

menstrual periods can vary from 1 to 8 days in length. This is usually normal. The average length of

the cycle (time between menstrual periods) is about 28 days, but there is no normal cycle length.

NUMERICAL SETS

Natural numbers

The natural numbers is formed by:

N = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9,...}


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Natural numbers count the elements of a whole, cardinal number, or express the order which

occupies an element in a whole, ordinal number. The natural numbers are ordered, which allows us

to compare two natural numbers:

5 > 3; 5 is greater than 3.

3 < 5; 3 is less than 5.

The natural numbers are unlimited, if 1 is added to a natural number, another natural number is

obtained.

Representation of the Natural Numbers

The natural numbers can be represented in a

straight line ordered from minor to major. On a

straight line, draw one point and mark it with

the number zero. To the right of the zero, and with the same separations, place in ascending order

the following natural numbers: 1, 2, 3...

Whole numbers

The set of whole numbers include the natural numbers and 0. Call this set W, then W = {

0,1,2,3,4,5,6,......} Reading and writing whole numbers can be explained by using the following

illustration. Take a close look and carefully study it!

Recall that the place value for 2, 4, and 6 are the hundred-thousands, the ten-thousands, and the

thousands respectively. Again, the position occupied by 2 is the hundred-thousands and putting a 2

is this position means that there are 2 hundred-thousands or two hundred thousand. In the same

way, putting a 4 in the ten-thousands position means that there are 4 ten-thousands


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or forty thousands because 4 tens is forty. Finally, putting a 6 in the thousands position means that

there are 6 thousands or six thousand. Putting it all together, we have

(two hundred) thousand + (forty) thousand + (six) thousand = ____________________________

(two hundred + forty + six)thousand = ____________________________

(two hundred forty six)thousand = 246 thousand ____________________________

What gives us the right to just add two hundred, forty, and six?

two hundred cars + forty cars + six cars. ____________________________

Would not you agree that it is equal to two hundred forty six cars?

The above is the same, except that instead of using cars, we are using thousand. The group name, as

shown in the illustration, is 'thousands' In general, it is unnecessary to say it three times. When

reading whole numbers, always read the numeral first, which is 246 and then the group name from

left to right. Therefore, we read

(two hundred) thousand + (forty) thousand + (six) thousand as

( two hundred forty six) thousand = 246 thousand.

By the same token, the next group name, which is 'millions' is read five hundred twenty million

= 520 million

The whole number can be read as:

(two hundred thirty four) billion (five hundred twenty) million (two hundred forty six) thousand

nine hundred seventy eight = ____________________________

(234 billion (520 million (246) thousand 978

Other examples

355,645 is read three hundred fifty five thousand, six hundred forty five

16,006,006 is read sixteen millions, six thousand, six

25,000,000,000 is read twenty five billion


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Rational numbers

Rational numbers are any numbers that can be written as a fraction. In other words, you can

rewrite the number so it will have a numerator and a denominator.

They have the form in which a and b are integers and b not equal to zero.

Notice that we said b cannot be zero. It is because any number divided by 0 has no answer.

Examples of numbers that are rational are:

, and 0

Now, why are 2 and 0 examples of such numbers? It is because 2 and 0 can be written as

x can be any number since 0 divided by any number is zero.

Decimal expansion:

We can also write rational numbers as a decimals. We do this by performing a

quick division that is dividing the numerator by the denominator. For instance,

Notice that you can continue division to keep getting zeros for the decimal

places after 4

The bar on top of 0 means that if we continue to perform long division, we will keep getting an

infinite number of zeros. Another way to convert into a decimal is to notice that we

can multiply 5 by 20 and 2 by 20.

Diving by 100 or any other power of 10 is a straightforward process.

If you are dividing by 10, just move the decimal point one place to the left.

If you are dividing by 100, just move the decimal point 2 places to the left.

and so forth... , the decimal point is after 0 for 40.


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COLOMBIA: OUR IDENTITY

Officially the republic of Colombia, is a country situated in the northwest of South America,

bordered to the northwest by Panama; to the east by Venezuela and Brazil; to the south by Ecuador

and Peru; and it shares maritime limits with costa Rica, Nicaragua, Honduras, Jamaica, Dominican

Republic and Haiti. It is a unitary, constitutional republic comprising thirty-two departments.

The territory of what is now Colombia was originally inhabited by indigenous peoples including the

Muisca, Quimbaya, and Tairona. The Spanish arrived in 1499 and initiated a period of conquest

and colonization ultimately creating the Viceroyalty of New Granada, with its capital at Bogot.

Independence from Spain was won in 1819, but by 1830 "Gran Colombia" had collapsed with the

secession of Venezuela and Ecuador. What is now Colombia and Panama emerged as the Republic

of New Granada. The new nation experimented with federalism as the Grenadine

Confederation(1858), and then the United States of Colombia (1863), before the Republic of

Colombia was finally declared in 1886. Panama seceded in 1903. Since the 1960s, the country has

suffered from an asymmetric low-intensity armed conflict, which escalated in the 1990s, but since

2000 has decreased considerably. Colombia is ethnically diverse, its people descending from the

original native inhabitants, Spanish colonists, Africans originally brought to the country as slaves,

and 20th-century immigrants from Europe and the Middle East, all contributing to a diverse

cultural heritage. This has also been influenced by Colombia's varied geography, and the imposing

landscape of the country has resulted in the development of very strong regional identities. The

majority of the urban centers are located in the highlands of the Andes Mountains, but Colombian

territory also encompasses Amazon rainforest, tropical grassland and both Caribbean and Pacific

coastlines. Ecologically, Colombia is one of the world's 17 megadiverse countries, and is considered

the most biodiverse per square kilometer. Colombia is a middle power with the third largest

economy in Latin America, is part of the CIVETS group of six leading emerging markets and is an


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accessing member to the OECD. Its principal industries include oil, mining, chemicals, health

related products, food processing, agricultural products, textile and fabrics, garments, forest

products, machinery, electronics, military products, metal products, home and office material,

construction equipment and materials, banking, financial services, software, IT services and the

automotive industry.

Patriotic symbols:

1. Flag: The yellow color symbolizes the great natural wealth of Colombia, the blue symbolizes the

sky and seas, and red, the blood spilled by our heroes.

2. The coat of arms of the Republic of Colombia: it is divided into three horizontal bands: the upper

band , on blue field , has in the center a gold Granada red open grained , with stem and leaves of

gold. On each side of the Granada goes a cornucopia of gold inclined, pouring coins into the

center of the right side, and proper fruits of the torrid zone of the left side. The name denotes the

Granada wearing this republic, and cornucopias, the richness of its mines and the fertility of

their land. The middle band in platinum field, has in the center a Phrygian cap horned into a

spear as a symbol of freedom, (Platinum, precious metals, our own country). At the lower end is

the Isthmus of Panama, with its two adjacent seas wavy silver and black ship with its deployed in

each candle .The condor symbolizing freedom. From its peak hangs a green laurel wreath and a

flowing ribbon, grabbed the shield and woven into the crown, the statement concerning gold

with black letters: Freedom and Order.

3. The national anthem of Colombia: was formalized by Law 33 of 1920. The anthem was written by

Rafael Nez and music by the Italian composer Oreste Sindici.

Patriotic icons:

1. Orchid: is the national flower of Colombia, named as such in 1936 by the Colombian Academy of

History. Its structure and colors are extraordinarily beautiful.


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2. The majestic Andean condor: symbolizes the sovereignty and freedom of Colombians. It has been

called "the eternal bird."

3. Wax palm: It is a palm of stunning beauty, extraordinary strength and legendary longevity. The

slenderness of the wax palm, is its height and its unique size.

4. Colombian emeralds: are the most beautiful and valued the world. The purity, brilliance and

transparency of these precious stones are the most important features for evaluation.

5. Coffee: is one of the most consumed beverages in the world and although Colombia is

considered one of the best producers. Colombian coffee is recognized as the best coffee in the

world and in several countries as a gastronomic excellence.

Natural regions of Colombia

Because of its natural structure, Colombia can be divided into six very distinct natural regions.

These consist of the Andean Region, covering the three branches of the Andes Mountains found in

Colombia; the Caribbean Region, covering the area adjacent to the Caribbean Sea; the Pacific

Region adjacent to the Pacific Ocean; the Orinoquia Region, mainly in the Orinoco river basin along

the border with Venezuela; the Amazon Region, part of the Amazon rainforest; and finally the

Insular Region, comprising islands in both the Atlantic and Pacific oceans.

Andean Region: The Andes mountains form the most populous region of Colombia and contain

the majority of the country's urban centers. They were also the location of the most significant pre-

Columbian indigenous settlement.

Caribbean Region: Is traversed by a number of rivers heading from the Andean highlands to the

sea, including Colombia's principal river, the Magdalena, which disgorges at the main port of

Barranquilla.


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Pacific Region: Is distinguished by its high humidity. Precipitation is among the highest in the

world, with an average of 4,000 mm per year, some areas that receive as much as 12,000 mm per

year.

Orinoquia Region: Is rich in oil and suitable for extensive ranching but sparsely populated.

Amazon Region: Is a region in southern Colombia over the Amazon Basin.

Insular Region: Is considered by some as a sixth region, comprising those areas outside continental

Colombia.

People

About 60% of Colombia's population are mestizos, and some one fifth are of European descent.

Indigenous peoples, who account for only about 1% of today's population, live on the edge of some

of the major cities and in remote areas. About 15% of the people are of mixed African and European

descent. The small (less than 5%) black population is concentrated along the coasts and in the

Magdalena and Cauca valleys. Spanish is the official language. The population is overwhelmingly

Roman Catholic. There are universities in all the major cities.

Food

Colombian Cuisine is very diverse and varies depending on the different regions of Colombia. In

some areas you will find specialties like roasted ants or guinea pigs while in other areas Colombians

wouldn't even touch those dishes. Colombia is not a paradise for vegetarians as the Colombian diet

includes a lot of meat. In the coastal areas you will find a good variety of fish, lobster and seafood

often prepared with a sauce made out of coconut milk. The offer of fresh fruit is overwhelming and

many of the varieties you have probably never heard of before. In general breakfast is quite

important in Colombia and consists of fruit juice, coffee or hot chocolate, fruit, eggs and bread.

Lunch which is served between 12 and 14pm is the main meal of the day at least in the


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countryside. A traditional main meal consists of a soup, a main dish, a drink and sometimes a

dessert which is generally very sweet. The dinner is more like a snack. In the big cities the main meal

often will be served around 7pm or 8pm.

Folklore

Colombian folklore seems to permeate culture here on a deep and perhaps, difficult level to grasp.

It's function is embedded in the search for meaning and significance in daily life that is often

portrayed through stories, music, carnivals and festivals, folk legends and proverbs. Although I

find it difficult, if not impossible, to fully understand Colombian culture, it seems that by paying

attention to their stories, told through music or oral tradition for example, that you get a glimpse

into the deeper meaning of the country. I recently met a man at a film festival who seemed to be at

the heart of Colombian folklore who told stories through the oral tradition. He told them with great

zeal and drama. I was surprised, expecting him to be calm but on the contrary, it's as though he was

acting the characters of his stories.

Touristic places

Tourism in Colombia is an important sector in the country's economy. Colombia has major

attractions as a tourist destination, such as Cartagena and its historic surroundings, which are on

the UNESCO World Heritage List; the insular department of San Andrs, Providencia y Santa

Catalina; and Santa Marta and the surrounding area. Fairly recently, Bogot, the nation's capital,

has become Colombia's major tourist destination because of its improved museums and

entertainment facilities and its major urban renovations, including the rehabilitation of public

areas, the development of parks, and the creation of an extensive network of cycling routes. With its

very rich and varied geography, which includes the Amazon and Andean regions, the llanos, the

Caribbean and Pacific coasts, and the deserts of La Guajira, and its unique biodiversity, Colombia

also has major potential for ecotourism.

sÍntesis de primer periodo

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