SCIENCE CONCEPTS FOR SECOND GRADING PERIOD

CORAL REEFS

Corals - Are tiny sea animals that live in colonies or groups. They secrete stony materials that become their outer skeletons. They have soft bodies but they have hard shell-like materials around their bodies. They are made of calcium carbonates secreted by tiny polyps.

Coral reefs - Are made up when corals die and their stony skeletons remains are come together.They come in different sizes, shapes and colors.

Importance of coral reefs:1. They serve as homes to different marine animals like fishes, crabs, snails, starfish, sea urchins and

algae.2. Rich sources of marine food.3. They also provide medicinal products and other resources.4. They can be used as jewelry and home and aquarium decorations.5. Serve as tourist attractions.6. White sand beaches are due to the fragments of coral sands.

Four Types of Coral Reefs:1. Fringing reefs – grow along border of islands and continents.2. Barrier reefs – grow between a landmass and an ocean.3. Platform reefs – grow in patches behind barrier reefs.4. Atolls – ring-shaped reefs that grow around the rims of a dead underwater volcano.

Destruction of coral reefs:1. Muro-ami fishing2. Use of dynamite and cyanide in fishing3. Other illegal fishing4. Collecting corals5. Urban development6. Industrial development 7. Dumping of waste by factories

Some ways to preserve the Coral Reefs:1. Making of artificial reefs. Artificial reefs may be built by using old tires, bamboos and concrete

materials. These act as reefs top attract corals and other marine animals.2. Help reduce pollution on land and in water by not throwing garbage in the seas.3. Rally against illegal fishing and oil spills in our bodies of water.4. Tell others about the importance of corals reefs and its preservation for future generations.5. Support the programs and projects of the government to protect our coral reefs.

PLANTS

Tropism – plant responsesa. Phototropism – response to lightb. Hydrotropism – response to waterc. Chemotropism – response to chemical substancesd. Thigmotropism – response to touch e. Geotropism – response to gravity

Chlorophyll – green pigment in plants. It is the only substance in the world that can capture sunlight, absorbing the blue and red light to form an energy rich substance called ATP (Adenosine Triphosphate).Cuticle – transparent skin of a leafChloroplast – small green packages found inside the cells.

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Xylem – are veins and venules which are made up of bundles of microscopic tubesPhloem – another bundle of microscopic tubes distributed to all the cells of the plantStomata – tiny openings found on leaves

Photosynthesis – is the process of manufacturing food in green plants. It involves the synthesis of carbon

dioxide and water in the presence of sunlight.

Raw materials needed in food making process are:a. chlorophyll b. carbon dioxide c. water d. sunlight

The end product of photosynthesis is a form of simple sugar.

The by-product of photosynthesis is oxygen.

Leaves are considered the food factory of plants.

Green plants can manufacture their own food because of chlorophyll.

Plants need air, water and sunlight in order to grow.

TENDRILS – help support the climbing plants.

Other Uses of Plantsa. Wood – bulk of which a tree is made of, is the basic material of all carpentry work.b. Paper – comes from trees. Most of our paper is made from cellulose found in wood, called pulp.c. Rubber – also comes from trees. Latex, the raw material of rubber, is the milky liquid or sap of a

rubber tree.d. Cloth, ropes and most kinds of thread come from the parts of plants called fibers.

Food from PlantsPlants are the producers ; Animals are the consumers

a. Many plants have edible leaves, and flowers.Ex. Cabbage, lettuce, cauliflower, brocolli

b. Some plants store food in their roots and stems.Ex. Carrot, cassava, asparagus, bamboo shoot

c. Plants store food in their fruits.Ex. apples, mangoes, guavas, squash, cucumber

d. Cereals are also fruits of some members of the grass family.Ex. Wheat, corn, oats

e. Some plants are not eaten as basic food but as flavors to give food a pleasant taste and/or smell.Ex. Ginger, oregano, pepper

f. Not all parts of a plant are edible.Ex. Cherry (fruit is edible but its leaves can harm you)

Plants as Medicinea. Alagaw – use to cure cough, gas pain and headacheb. Duhat – cures diarrhea & woundsc. Avocado leaves – used to cure rheumatism

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d. Garlic – cures arthritis, rheumatism & insect bitese. Sambong – for chest pain, cough, & headachef. Ikmo leaves – gas pains & cough

Protective Structures of Plantsa. Thorns/Spines Ex. Rose, cactus and bamboob. Hard Slippery Shell Covering Ex. Atis, chico and tamarindc. Foul odor Ex. Alugbati and duriand. Bright colore. Poisonous – Ex. Some species of mushrooms, death cap, amanita, mold, rosary pea, poison ivy

Adaptations for Propagation of Speciesa. Flowers and seeds are the reproductive organs of plants. b. Most flowers contain both male (stamen) and female (pistil) reproductive structures. Bees are

nature’s most important agents of cross-pollination.c. Insects like moths, butterflies and bees are nature’s most important agents of cross-pollination

Butterflies & bees – pollinates bright colors and fragrant flowersMoths – pollinates white and yellow flowers with sweet scentsBats – pollinates scented flowersFlies – pollinates flowers with unpleasant smells

d. Flowers that are wind-pollinated have a great deal of very light pollen grains and produce a sticky pistil.

PHOTOPHYLIC – plants that adapt to intense light.Ex. Sunflower, legumes, grass

PHOTOPHOBIC – plants that grow in shady areas.Ex. Mosses, liverworts

PARASITES – non-green plants that survive because they get their food from other living things.

SAPROPHYTES – plants that live on the body of a once living thing.

Plants Growing in a Specific Environmenta. TERRESTRIAL OR MESOPHYTES – plants that live on land. Ex. Coconut, bamboob. AERIAL OR EPIPHYTES – plants that live in air. Ex. orchidsc. AQUATIC OR HYDROPHYTES – plants which live in water. Ex. Water lily

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Plants can be classified into:

Nonvascular plants, Bryophytes or Simple

Plants

Moss Plant Liverworts Hornworts

Tracheophytes, Vascular Plants or Tube Plants

Fern Plants Seed Plants

Gymnosperms or Cone-bearing Plants

Angiosperms or Flowering Plants

Monocot Dicot

TRACHEOPHYTES, VASCULAR PLANTS OR TUBE PLANTSa. ANGIOSPERMS – are flowering plants. In this phylum, reproduction takes lace in the flower. The

term angiosperm is derived from the Greek words that mean “enclosed seed”.b. GYMNOSPERMS – derived from the Greek words that mean “naked seed”. They are so called

because their seeds are exposed and borne in cones.c. FERN – reproduce spores. They have no seeds but contain groups of round organs on their

underside, called sporangia which contain the spores.

CLASSIFYING BY SEEDSa. Monocotyledons or Monocot – seeds with only one food part.b. Dicotyledons or Dicot – seeds with two food parts.

PARTS OF A PLANT MONOCOT DICOT1. Leaves parallel leaf veins netted leaf veins2. Seeds (number of

cotyledons)one cotyledon two cotyledon

3. Roots fibrous taproot4. Flowers (petals) Flower parts in 3’s Flower parts in 4’s or 5’s5. Stems Scattered vascular bundle

arrangementCircular arrangement of vascular

bundle

MIXTURES AND SOLUTION

MIXTURES – is a material composed of two or more substances which are physically combined without losing their individuals properties.

Physical combination means that the parts of the mixtures retains their original composition and properties.

Types of Mixtures:a. Homogeneous mixture – parts cannot be distinguished from one anotherb. Heterogeneous mixture – components of the mixture are still visible

Methods of Separating Solid from a Solida. Flotation – when one solid in a mixture is heavier than water and the other is lighter, they can be

separated by stirring the mixture in water, one floats, the other sinks.b. Solution – when one solid in a mixture is soluble in water and the other is not, they can be

separated by stirring the mixture in water; one dissolves and the other remains in suspension.c. Using magnet/magnetic separation – when one solid in a mixture is magnetic and the other is not;

they can be separated by using a magnet; the magnetic material is attached, the other remains.d. Screening/Sieving – when one solid in a mixture is smaller than the other, they can be separated by

screening; the smaller particles pass through the screen, while the bigger ones remain.e. Manual Separation

Method of Separating a Solid Suspension in a Liquida. Sedimentation – is the process of allowing the suspended particles of an undisturbed suspension to

settle at the bottom of the container.b. Coagulation – is a process of speeding up sedimentation by the addition of a coagulating agent.c. Filtration – is the process of allowing the liquid part of a suspension to pass through a filter in

order to separate it from the solid part.d. Centrifuging – is a process of spinning a suspension by means of a centrifuge in order to separate

the heavier solid particles from the liquid.e. Distillation – is used even when the solid is dissolved in the liquid, and is the liquid that needs to

be retrieved.

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SOLUTION – it forms when the solid substance dissolved and it disappears in the liquid

COMPONENTS OF A SOLUTION:a. Solvents – are substances that dissolves materials or substances. Ex. water, acetone, thinner

Water is considered the UNIVERSAL SOLVENTb. Solute – are solid substances that are soluble in another substance. Ex. salt, sugar

Rate of Solubility of a Solute can be Increase Through the Following Factors:a. Temperature of the solventb. Stirringc. Size of Solute (Powdering/Pounding/Pulverizing/Grinding)

Suspension – its particles have the tendency to settle at the bottom of a container.

Colloid – when there is a presence of fine particles that remain in the solvent if left undisturbed and can be seen by the aid of the sunlight or a flashlight

POLLUTION

Pollution is often cause by domestic, industrial, commercial and agricultural wastes. Such as fertilizer, pesticides, insecticides, carbon dioxide, lots of smoke, decayed plants and animals. These things that cause pollution called pollutants.

Methane gas is usually emitted by decaying materials pollute the air.

CFC(chlorofluorocarbons) is an air pollutant that comes from hair sprays and air condition.

Fuels of cars and some factories produce waste products that go to the atmosphere. Some of these are SULFUR DIOXIDE and NITROGEN OXIDE. When these combine with moisture in the air, they become acid and when rain clouds absorb them they will fall as acid rain. This cause death to plants.

Ways of preventing land, water and air pollution.

1. Make compost for biodegradable materials instead of burning them.2. Planting more trees prevent pollution too, because trees absorbed impurities from the air.3. Handle & dispose chemical substances properly.4. Minimize the use of aerosol products.5. Instead of commercial fertilizer, use organic or compost more often.6. In big cities and communities, there should be sanity landfill where trashes are to be dumped.

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