Ontario Teachers' Manuals: Nature Study Part 37

Find the stamens and describe as to number and position; find out how the stamens are fitted to ensure that the pollen will get upon the visiting insects.

Find the pistil and describe its shape. How is the stigma fitted for receiving the pollen that is carried by the insect visitors.

_To the teacher._--The trilliums attract insects by their large white and purple flowers, which are held up by their long stalks high above the three broad leaves. The strong carrion-like odour of the purple trillium is attractive to flies and beetles, while bees and b.u.t.terflies find the fragrance of the white trillium more to their liking.

The root-stock serves as a buried store of food to tide the plant over the drought of late summer and the severe cold of winter. The well-stocked cellar also explains the flouris.h.i.+ng condition of the plant in early spring. The six stamens stand on close guard around the pistil, and insects forcing their way to the nectaries are well peppered with pollen.

Continue the observation work by means of field exercises such as the following:

What change takes place in the colour of the white trillium as it grows old?

Find the ripened seed pods of the trillium, open them, count the number of chambers, and examine the seeds.

Do trilliums grow from the same root-stock year after year?

As correlations, represent the trillium in colour and design an embroidery pattern based on it.

Lessons similar to that on the trillium may be based on adder's tongue, Indian turnip, Dutchman's breeches, violet, and clover.

ADAPTATIONS OF ANIMALS

It is not considered necessary to go outside the list of ordinary animals to find sufficient ill.u.s.trations of adaptations, and it is recommended that attention be given to these during the study of animals prescribed for the regular Course. This may be supplemented by an occasional review of adaptive features for the purpose of emphasizing the general fitness of animals for their varied habits and surroundings.

Care must be taken lest the attempt to explain structures by adaptation be carried to an extreme, for it is impossible to account for all the variations in animal forms.

The following list contains a few of the many examples of adaptations to be met with in the Course prescribed for Forms II and III.

The horse walks and runs on the tips of its toes; this gives greater speed.

Wild animals of the cow and deer kind can swallow their food hastily so that they may retire to a safe retreat; there they regurgitate the food and chew it. The domesticated animal retains this habit, though there is no longer a need for it.

The wood-hare's fur is brown in summer, hence its enemies cannot see it against the brown gra.s.s and moss; in winter its colour is white, which, against the snow, is a protective colour.

The porcupine is very slow, but its colour and shape make it almost impossible to distinguish from a knot on a log. Its quills form an effective protection when it is discovered.

The feet of the squirrel are adapted for climbing and its teeth for gnawing wood and for opening nuts. The tail serves as a balancing pole for leaping from tree to tree and in winter it acts as a protection from cold.

The earthworm's shape and movements are suited to its habits of burrowing through the soil. Its habits of swallowing the soil fit it for burrowing and for obtaining its food at the same time.

Many insect larvae, as the tomato worm and the cabbage-worm, are of the same colour as the plants on which they feed, and this enables them to escape detection by birds.

The larvae of dragon-flies and May-flies breathe in water by means of gills very much as fishes do, but the adult forms are suited for breathing in air.

Female birds are usually dull gray or mottled, so that their colours blend with their surroundings while they are nesting, and hence they do not attract the notice of their enemies.

Birds that swim have webbed feet, which act as oars for pus.h.i.+ng them through the water. Their feathers are compact and soft for warmth, and these properties, together with oil on their surfaces, make them waterproof.

The tongue of the woodp.e.c.k.e.r is long, spear-shaped, and sticky; hence it is adapted for catching insects in the holes pecked into the wood.

The tongue of the toad is fastened at the front end, so that a flap can be shot out for more than an inch in front of the animal, thus enabling it to catch insects on its sticky surface.

The toes of the frog are webbed to make them more serviceable in swimming.

The tail of the musk-rat is strong and broad like the blade of an oar and serves the same purpose as an oar.

The tail of the fish is more serviceable for swimming than legs would be.

BIRD TYPES

WOODp.e.c.k.e.rS

Woodp.e.c.k.e.rs are easily distinguished from other birds by their habit of perching in a vertical position on the trunks of trees with the tips of their tails pressed against the bark. While in this position, they tap upon the tree with their sharp, pointed beaks.

THE DOWNY WOODp.e.c.k.e.r

Learn to recognize the smallest of our woodp.e.c.k.e.rs, the Downy. Winter or summer it may be found among the apple trees and shade trees, a tiny black and white bird little bigger than a wren.

OBSERVATIONS

I

Why is "checkerboard" a good name for this bird?

Are there any distinct lines of white?

Are there any patches of red?

Do its movements reveal energy or listlessness?

How does it move up a tree trunk?

How does it move down a tree trunk?

Find out how it can hold so firmly to the trunk.

Does it use its sharp beak as a drill or as a pick?

_To the teacher._--The downy is spotted black and white, with barred wings and a white line down the centre of the back. A bright scarlet crown is the colour distinction of the male. This little bird is the embodiment of energy and perseverance. It hops nimbly up the trunk, tapping here and there with its beak, and then listening for the movements of the disturbed wood-borers. If it wishes to descend, it wastes no time in turning around, but hops backward down the trunk, or jumps off and flies down.

II

Examine an apple tree upon which a downy has been at work and find out what it was doing there.

Do you find the birds in pairs during winter? During summer? Distinguish the male from the female.

Tie a beef bone with sc.r.a.ps of meat adhering to it to a tree. What birds come to it?