Continuation: Air Movements

• Winds change in strength and direction within the year.
• Winds are affected by mountains, continents, and oceans.
• They grow colder while rising over mountains. They become warmer as they sink. In summer winds are warmed by continents and warmed by oceans. Continents and oceans exposed to sunlight absorb heat in the same way as they do the seashore and the sea.
• Generally, high pressure centers develop over the oceans and low pressure centers over the continents in summer.
• In winter, the high pressure centers are over the continents and the low pressure centers over the oceans.
  
• Isobars - lines of equal pressure that include many island separated by seas.

• Monsoons - winds that blow by season toward either continents or oceans because of differences in air temperature and air pressure.

THE WIND SYSTEMS IN THE PHILIPPINES

• The cold air from the high pressure area in Siberia moves toward the low pressure area over the north Pacific Ocean. But the Coriolis effect gradually turns it to the right in a giant arc that reaches the Philippines from the northeast direction. This large mass of moving air passing over the Philippines, called the northeast monsoon, is drawn to the low pressure center over Australia. This wind system is locally called AMIHAN. The figure below shows the Northeast Monsoon or Amihan (November - February)
  

• The highest temperature in the Philippines occur from march to May, resulting in warm rising air over the country. The northeast trade winds occasionally rise over this warm rising air.
• From June to about September, sometimes until October or even November, the Philippines is in the path of strong winds that start from southern hemisphere. These winds originally blow from southeast direction coming from the area of Australia.
• The area between northwestern India and Pakistan becomes a heat center, thus a low pressure area. The winds from Australia move toward the low pressure area at or near the equator, slowly turning , slowly turning left while in the southern hemisphere. When the winds cross the equator they begin to turn right due to the Coriolis effect. They are drawn instead to the low pressure center over India and pakistan, first passing over the low pressure center over India and Pakistan, first passing over the Philippines from a southwesterly direction. This wind system appears from about June to November and is called the Southwest Monsoon or Habagat. The figure below shows the southwest monsoon or habagat (June - September).
  

• Habagat brings much rain throughout the country, having absorbed moisture from the surrounding seas before reaching the Philippines.
• During the monsoon periods farmers take advantage of the rains to irrigtae the ricefields and start the planting season.
• For fisherman the monsoons mean less catch because they cannot go far out to sea. At these times of the year the seas are very rough and dangerous. The monsoons are thus both beneficial and harmful.
  

THE WATERS OF THE EARTH

INLAND WATERS

· Inland bodies of water are mainly streams, lakes, and ground water.

· A stream is consists of running water in a naturally formed channel which begins in elevated area and usually ends in the sea or lake.

· Rivers are permanently streams with flowing water throughout the year.

· Brooks, creeks, and rivulets are smaller channels of running water which may or may not be permanent.

· A stream on a steep slope with fast flowing water forms a rapid.

· A stream dropping over a precipice or the vertical side of a mountain forms a waterfall.

· The Philippines has over 700 principal rivers.

· Cagayan River in Northeastern Luzon is the longest and largest.

· Lakes are large bodies of standing held in deepened areas of land called basins.

· Ponds are much smaller and shallower bodies of standing water than lakes.

· Swamps are generally wider than ponds or lakes but are shallower because of sediment deposited at the bottom. Swamps are usually overgrown with vegetation.

THE DISSOLVED SUBSTANCES IN INLAND WATER

· The most important gases dissolved in water are oxygen and carbon dioxide.

· Oxygen is needed for the respiration of aquatic animals.

· The maximum concentration of dissolved oxygen in water decreases as the temperature of water increases.

· At the same temperature, more oxygen dissolves in inland fresh water than in sea or ocean water due to high salinity in sea or ocean water.

· Pollution affects the dissolved oxygen in water. Bacteria in the water break down the pollutants into simpler and not harmful substances. The process uses dissolved oxygen. Large amounts of pollutants remove large amounts of dissolved oxygen.

· Dissolved carbon dioxide in water is used by aquatic plants, mostly microscopic organisms known as plankton, in photosynthesis. Photosynthesis occurs in sunlight. The carbon dioxide concentration of water, therefore, decreases in daylight and increases at night.

· Some amount of carbon dioxide combines with water to form carbonic acid. Carbonic acid can dissolve calcium carbonate in seashells. Given time, the shells of dead animals of can be dissolved by carbonic acid and be made available for further shell formation of aquatic animals.

· Hydrogen sulfide, methane, free ammonia, nitrogen and few other gases also dissolve in inland waters. Most of them are dissolved from the atmosphere. Hydrogen sulfide and methane are also produced when decomposition caused by bacteria takes place in water.

· In sea water, the most abundant dissolved solid is sodium chloride. In fresh water, calcium and magnesium are generally more abundant. Calcium is needed by aquatic animals for shell formation. Magnesium is used by plants in the formation of chlorophyll, a substance needed for photosynthesis.

CARE OF THE EARTH’S WATERS

· Good quality water in lakes and rivers as well as in seas and oceans encourages an abundance of fish and other living things to bred and thrive in them.

· Good quality inland waters are also source of water supply for drinking, cooking, cleansing, and other domestic uses.

· Many modern activities lead to the destruction of water areas. Boats and ships leak oil into the water. Sea oil exploration and extraction destroy the breeding places of fish and seashells and pollute and industrial chemicals run off into water bodies and seep into ground water reservoirs to pollute them. Mining destroys ground water deposits. Industrial plants, mines and cities should remove pollutants from waste water before draining it into rivers and lakes.

· Excessive use of water can be avoided in many little ways at home. Never leave tap water running while you soap and rub your hands or brush your teeth. Open it only when you are ready to use water. Reuse water whenever possible. Wash water used in washing clothes can be reused for cleaning floors and toilets. Take care not to pollute bodies of water. Rivers and lakes should not be used as garbage and waste water dumps.

· Treated sewage and waste-water released into rivers, lakes, and seas are less damaging than the untreated. Forests hold water longer in the ground. Prevent flooding in the surrounding lower areas, and supply water during the dry months. The denudations of forests reverse these effects. During the rainy months, water can be collected in man-made dams and reservoirs.

Earth Science: THE MOVEMENT OF OCEAN WATERS

1. WAVES

• The highest point of a wave is the CREST, and the lower point, the TROUGH.

• The length of a wave is the distance from one crest to the next crest, or from one trough to the next trough.

• The stronger the winds blow, the bigger the waves formed

• In open ocean, the longer distance the waves travel, the higher and longer they become.

• A Mass or rocks and soil that slides into thw ater from the edge of land disturbs the water and forms waves. This is a LANDSLIDE into the sea.

• The larger the mass of the rocks hitting the water, the larger the waves formed.

• In May 1960, giant waves from the Pacific Ocean hit the shores of Polollo Island off Quezon province. In August, 1976 giant waves destroyed the coastal towns of Cotabato and Davao. Undersea earthquakes were reported as the cause in both events.

• TSUNAMI refers to the giant waves formed by undersea earthquakes, volcanic eruptions and landslide.

• Tsunami are about 150 km long, traveling at about 800 km/h. They increase in height while traveling, rising as high as 30 m as they approach shore.

2. OCEAN SURFACE CURRENTS

• Flowing water carries floating objects away. The flow of the surface water of seas and oceans is known as surface currents. Surface currents mix and redistribute water in the oceans.

• Records of sailing ships and data from observations made by oceanographers show that ocean surface waters flow in large circulating currents. These circulating currents maintain their directions.

• Surface currents are driven mainly by winds. The easterly winds pushing surface water toward the equator form the equatorial currents.

• The presence of land in the path of the equatorial currents turn them to the right in the northern hemisphere and to the left in the southern hemisphere. Beyond the 30 N ans S latitudes the westerly winds push the currents. The turning to the right in the northern hemisphere and to the left in the southern hemisphere is called the Coriolis effect which is caused by the earth's rotation.

• The Gulf Stream of the North Atlantic Circulation is the fastest and strongest of the major currents. Part of the Benguela Current from the South Atlantic Circulation joins the Gulf stream and adds to its volume and speed.

• The current in the Indian Ocean is the only one which changes direction with the monsoon seasons. When the southwest monsoon wind blows, the Indian Ocean Current flows eastwest monsoon wind blows, the Indian Ocean season Current flows eastward. When the northern monsoon wind blows, the current flows westward.

• The Antarctic Circumpolar Current flows in a west to east direction around the Antarctic Continent. There are no land masses block and turn it. Being driven by winds coming from the west, it is also called the West Wind Drift.

• In the middle of each circulation is calm water. The best known of them is the Sargasso Sea in the North Atlantic Circulation. The name Sargasso is taken from the brown seaweed Sargassum growing abundantly in its calm water. Once caught there, they had to wait long for strong winds to push their sails and get them out.

• Surface currents are still useful today in water transportation. Although modern ships run on fuel, they move faster on less fuel by following the currents.

3. DENSITY CURRENTS (to be continued)

Lesson Plan: Mitosis

A. Subject Name: Mitosis

B. Lesson Reference: Lesson 47

C. Lesson Title: Mitosis

D. Lesson Description:
Cell division is an elegant process that enables organisms to grow and reproduce. Through a sequence of steps, the replicated genetic material in a parent cell is equally distributed to two daughter cells. While there are some subtle differences, mitosis is remarkably similar across organisms.

Before a dividing cell enters mitosis, it undergoes a period of growth called interphase. Interphase is the "holding" stage or the stage between two successive cell divisions. In this stage, the cell replicates its genetic material and organelles in preparation for division.

E. Learning Output
E1. Identify the stages of mitosis.
E2. Describe the events occur in each stage of mitosis.
E3. Illustrate the stages of mitosis.

F. Review of Previous Learning/Lesson
The most basic function of the cell cycle is to duplicate accurately the vast amount of DNA in the chromosomes and then segregate the copies precisely into two genetically identical daughter cells. These processes define the two major phases of the cell cycle. DNA duplication occurs during S phase (S for synthesis), which requires 10–12 hours and occupies about half of the cell-cycle time in a typical mammalian cell. After S phase, chromosome segregation and cell division occur in M phase (M for mitosis), which requires much less time (less than an hour in a mammalian cell). M phase involves a series of dramatic events that begin with nuclear division, or mitosis.

G. Learning Presentation
Refer to the two videos below for the lecture on Mitosis.







H. Learning Activity

Refer to the link:
http://bio.rutgers.edu/~gb101/lab2_mitosis/section1_frames.html

I. Learning Evaluation

Refer to this link : http://quizstar.4teachers.org/index.jsp

Xylem and Phloem

The xylem is the principal water-conducting tissue of vascular plants. It consists of tracheary elements, tracheids and wood vessels and of additional xylem fibres. All of them are elongated cells with secondary cell walls that lack protoplasts at maturity. Bordered pits are typical for tracheids, while wood vessels are marked by perforated or completely dissolved final walls.

Phloem is the vascular tissue plants use to transfer sugars from sites of production or storage to locations where energy is needed. In contrast to xylem, phloem tissues are living. Sieve tube members connect at specialized areas called seive plates. At maturity the seive tube members lose their nuclei and fill with a complex proteinaceous material called cell sap. Sugars are transported through the cell saps of adjacent cells.

In losing their nuclei, sieve tube members lack the molecular control mechanisms most living cells possess. Nucleated cells adjacent to sieve tube members appear to take over the control of cellular functions within these phloem transport cells. These nucleated cells are appropriately called companion cells.

Sieve plates are specialized areas where materials flow through tiny pores from one sieve tube member to another.
Most phloem cells are parenchyma cell types. Sometimes phloem tissues contain sclerenchyma fibers for support.

External and Internal Parts of Plant Organs

Plant Hormones

Auxins promote stem elongation, inhibit growth of lateral buds (maintains apical dominance). They are produced in the stem, buds, and root tips. Example: Indole Acetic Acid (IA). Auxin is a plant hormone produced in the stem tip that promotes cell elongation. Auxin moves to the darker side of the plant, causing the cells there to grow larger than corresponding cells on the lighter side of the plant. This produces a curving of the plant stem tip toward the light, a plant movement known as phototropism.

Auxin also plays a role in maintaining apical dominance. Most plants have lateral (sometimes called axillary) buds located at nodes (where leaves attach to the stem). Buds are embryonic meristems maintained in a dormant state. Auxin maintains this dormancy. As long as sufficient auxin is produced by the apical meristem, the lateral buds remain dormant. If the apex of the shoot is removed (by a browsing animal or a scientist), the auxin is no longer produced. This will cause the lateral buds to break their dormancy and begin to grow. In effect, the plant becomes bushier. When a gardener trims a hedge, they are applying apical dominance.

Gibberellins promote stem elongation. They are not produced in stem tip. Gibberellic acid was the first of this class of hormone to be discovered.

Cytokinins promote cell division. They are produced in growing areas, such as meristems at tip of the shoot.

Abscisic Acid promotes seed dormancy by inhibiting cell growth. It is also involved in opening and closing of stomata as leaves wilt.

Ethylene is a gas produced by ripe fruits. Why does one bad apple spoil the whole bunch? Ethylene is used to ripen crops at the same time. Sprayed on a field it will cause all fruits to ripen at the same time so they can be harvested.