Grade Six Science
Hello Boys and Girls,
Was your past week a good one? Did you treat your fathers very specially last week? Have you been doing your best? Have you been having fun finding out about fish? Were you able to catch any fish and make your own aquarium? Let’s see what you remember about fishes before going on.
A. True / False
1. Fishes are invertebrates.
2. All fishes are covered with scales. 3. The pectoral fins are paired fins. 4. Some fishes can be classified as fish.
B. Which one is correct in each of the following? 5. Fishes usually breathe using their
a. lungs. b. gills.
6. The scales of fish point a. backwards. b. forwards.
7. Which fins help to propel the fish? a. Pelvic b. Caudal
8. The operculum covers the a. ears. b. nose. c. skin. c. inwards. c. Anal c. gills.
C. Draw a fish and name its parts. State the function of these parts.
This week let us turn our attention to another class of animals—Amphibians.
Can you name some amphibians? Yes, frogs, toads, newts and salamanders are amphibians. The word amphibia means both lives. This refers to the fact that although these animals mainly spend their adult lives on land, they begin their lives in water.
Amphibians have four limbs. They are used to make several movements such as hopping, jumping and crawling. Look at the feet of most amphibians. What type of feet do they have? Yes, they have feet with webbed toes. (Do you remember which other animal(s) has webbed feet/ toes?) The webbed feet help them to swim well.
Look again at the frog’s body. Do you see a neck or a tail? Are all amphibians like this? No, newts and salamanders have tails.
On what do frogs and toads feed? They feed on insects, such as flies. Have you ever seen its long tongue? The tongue is attached to the front of its mouth. This helps it to quickly and freely flick it out to catch the insects.
Amphibians lay their eggs in water. When hatched the young ones do not resemble the adult amphibian. As they grow they develop and change their forms several times before they become adults. These changes are referred to as metamorphosis.
Amphibians adults lay their eggs in water are cold blooded (most) are covered with moist, smooth skins breathe through gills when young and through lungs when they are
Stop for a moment and read as much as you can on amphibians. Find a diagram of the metamorphosis of a frog.
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?
By about eight weeks, these tadpoles develop back legs, then after this the front legs develop. Next the tadpoles lose their eternal gills and develop internal gills. The tail gradually shrinks and then lungs develop, replacing the internal gills. All of this prepares the frog to move to land. When all this is finished, the frog hops on to land. We see here that amphibians undergo metamorphosis, a complete change.
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.
We will continue to look at this next week. Until then be good, Boys and Girls, and be safe!