SCIENCE AND HEALTH 4( Ms. Sarah Gay R. Garcia)

SCIENCE AND HEALTH 4

COVERAGE:

A.  COMMON AILMENTS OF THE DIGESTIVE SYSTEM

B. CARING FOR THE DIGESTIVE SYSTEM

C.  ANIMAL REPRODUCTION ( SEXUAL AND ASEXUAL)

D.  OVIPAROUS AND VIVIPAROUS ANIMALS

E. LIFE CYCLE OF SOME ANIMALS

F. DANGERS POSED BY SOME ANIMALS TO PEOPLE

A. COMMON AILMENTS OF THE DIGESTIVE SYSTEM

1. Diarrhea-  an ailment  of the digestive system characterized by excessive loose bowel movement. Eating foods that are not clean, such as street foods can cause diarrhea.

2. Ulcer- is a sore or hole in the stomach or intestine.

3. Appendicitis-  is the swelling of the appendix. Appendix is the small organ found at the point where small and large intestines meet. An inflammed appendix is removed through an operation called appendectomy.

4. Constipation- refers to difficulty in moving the bowels. Feces become hard and dry due to lack of water and fibers.  Drinking lots of water and plenty of fiber rich food such as fruits and vegetables can prevent constipation.

5. indigestion- caused by eating hurriedly and by overeating.

6. mumps- highly contagious viral disease that affects the salivary glands. The affected glands become inflamed and swollen causing the  part below the ear to bulge.

7. toothache-caused by tooth decay.

B. CARING FOR THE DIGESTIVE SYSTEM

1. Eat nutritious food and foods rich in fiber.

2. Drink at least 6-8 glasses of water each day to prevent constipation.

3. Avoid skipping meals.

4. Chew your food well and do not eat hurriedly.

5. Wash your hands with soap and water.

6. Develop the habit of moving your bowels regularly.

C. ANIMAL REPRODUCTION ( SEXUAL AND ASEXUAL)

A hen and a dog can both produce their own young. However they differ in the manner of giving birth to their young.

Reproduction- the process in which living things produce offspring or young of their own kind.

Asexual reproduction- do not need a partner from the opposite sex to produce offspring.

Ø  Sponges reproduce through budding.

Ø  Amoeba reproduces through binary fission. Amoeba splits into half, resulting in 2 identical organisms.

Sexual reproduction- sperm cell from a male animal unites with and fertilizes the egg cell of female animal.

Fertilization- the union of sperm and egg cells to produce a fertilized egg

Ø  Internal fertilization- egg cell is fertilized inside the body of the female animal.

Ø  External fertilization- male and female animals release their sex cells in the water.

D.  OVIPAROUS AND VIVIPAROUS ANIMALS

Oviparous animals-animals that lay eggs

Parts of a chicken egg

1. shell- surrounds and protects the inner parts of the egg

2. eggyolk- provides food for the embryo

3. albumen or egg white- provides water and protects the embryo

4. chalazae- the two strands attached to the egg yolk holds the egg yolk within the albumen

5. shell membrane- protects the albumen and the eggyolk.

6. air space

Viviparous animals- give birth to their young alive

Ø  Placental mammals- animals that obtain food from its parent through the placenta. Examples are pig, horse, elephant

Ø  Marsupial mammals-  young that are born are not yet fully developed and stays in a protective pouch of the mother like the kangaroo

Ø  Monotremes- mammals that lay eggs but nurse their young after hatching like the platypus.

E. LIFE CYCLE OF SOME ANIMALS

Metamorphosis- the change in form and appearance of animals from eggs to adult

Ø  Complete metamorphosis-  four stages in the life cycle(egg, larva, pupa, adult)

Ø  Incomplete metamorphosis- three stages in the life cycle( egg, nymph, adult)

Summary of the life cycle of a butterfly:

Female butterfly lays its eggs. Egg hatches into tiny wormlike larva called caterpillar. The caterpillar attaches itself to a twig and turns into a pupa. The chrysalis cracks and a beautiful butterfly comes out.

            Chrysalis- the covering of the pupa during metamorphosis of a butterfly

Summary of the life cycle of a mosquito:

Adult female mosquito lays its eggs in stagnant water. Eggs hatches into a larva called wrigglers. Wrigglers float on the surface of the water with their heads down. The pupa develops into adult mosquitoes.

Summary of the life cycle of a cockroach:

Cockroaches lay their eggs in dark places. The eggs hatch into nymphs. Nymphs undergo a series of molting until they develop into adult cockroaches.

         Nymphs- look like adult cockroaches but do not have wings and are smaller in size

         Molting- shedding of outer covering

Summary of the life cycle of a frog:

Frogs lay their eggs in the water. Egg hatches into a tadpole. Hind legs appear followed by the front legs.

The tail becomes shorter .The tadpole begins to look more like an adult frog. The young frog turns into an adult frog.

                    

F. DANGERS POSED BY SOME ANIMALS TO PEOPLE

Anopheles- a type of mosquito that spread malaria

Aedes aegypti-  type of mosquito that spread dengue

Cockroaches and flies- can contaminate food.

Rabies- fatal disease caused by virus that attacks the nervous system .This disease is characterized by increased salivation and abnormal behavior that may eventually lead to paralysis and death.

Parasites- animals that live in another living organisms (called host) and depends on it for food. Examples are lice, ticks, hookworm, roundworm pinworm, aphids, termites