Grade Six Science

Amphibians and Reptiles Hello Boys and Girls,

How have you been over the past week? Have you been doing lots of activities in Science at school? I hope that you enjoyed looking at the frog. How well did you do the exercises that were at the beginning of the last article? Did you revisit the previous work done to check your answers?

Let’s continue our investigation of amphibians, (I hope you read a lot on them.)

Let’s have a look at the life cycle of a frog.

The frog lays its eggs in water. When they hatch they do not look like the adult frog. They have long tails with which they swim. Have you ever seen them in plentiful supply swimming about in the water? They have a head, fins and external gills. They live in the water. What are they called? Yes, they are tadpoles.

Let’s turn our attention to the toad. Have you ever seen a toad? How does it look? Yes, it looks like a frog but it is bigger and its skin is warty. Let’s see further how the frog and toad differ.

Wow! There are so many differences. The next time you see a frog or a toad , you can make some checks.

Let’s review some of what we have learnt about the frog so far. 1. They are found in a warm environment.

2. Their body is divided into head and trunk. The tail may or may not be present.

3. The skin is smooth and rough without any scales, but with glands that

make it moist.

4. They are carnivorous.

5. They have no paired fins. Unpaired fins might be present.

6. They have two pairs of limbs for locomotion.

7. They respire through the lungs and skin. Gills might be present externally

in some adults.

8. The heart is three chambered.

9. Fertilization is usually external. However, in salamanders, the fertilization

is internal.

10 Development is through metamorphosis.

11. They lay their eggs in water.

Let’s move on to investigate

Reptiles.

Can you name a few reptiles?

Snakes and lizards, crocodiles and alligators, and turtles and tortoises are all reptiles. Reptiles are all vertebrates.

Try to get pictures of reptiles and observe them. Do they have necks? Do they all have tails? Most reptiles have two pairs of limbs and a tail. (Do snakes have tails? How do they move?)

How do reptiles use their limbs to move? Reptiles use their limbs to creep, crawl, run, fight, swim and climb. Have you ever seen a turtle? Have you seen their thick strong limbs? These help them to support their body weight. When you get the chance, look at lizards as they climb. You may be able to see the suction pads that they have at the tip of the ‘toes’ of each limb. Look carefully at the claws of the crocodiles. Turtles have flat long flippers which make them good swimmers.

Have you ever seen how the skin of reptiles is thick, usually forming scales or plates? These scales or plates may be smooth or rough, and prevent them from drying out.

1. Name four amphibians.

2. What are five reptiles that you know. 3. Draw a few of them.

4. Name their external parts.

Until next week, DV, work as hard as you can. Goodbye.