Topic: Birds – adaptations for flight

Author: Zyta Sendecka

Target group

6th grade student of elementary school.

Core curriculum

12) Birds. Student:

a) presents the diversity of habitats and morphological features of birds,

b) observes representatives of birds (photographs, films, diagrams) and indicates adaptations for flight,

c) identifies birds as warm‑blooded animals,

d) presents the manner of reproduction and development of birds,

e) presents the importance of birds in nature and for humans.

Lesson objectives

Students describe the birds’ adaptations for flight.

The criteria for success

• you will list five types of the birds' adaptation to flying;

• you will describe the structure and functions of feathers.

Key competences

• communication in the mother tongue;

• communication in foreign languages;

• mathematical competence and basis competences in science and technology; 

• digital competence;

• learning to learn;

• social and civic competences.

Methods/forms of work

Talk, brainstorming, indirect observation, working with the text.

Individual activity and activity in groups.

Teaching aids

• abstract;

• interactive whiteboard or traditional blackboard;

• different types of feathers;

• table tents.

Lesson plan overview

Introduction

1. The teacher specifies the subject of the lesson and the criteria for success.

Realization

1. The teacher suggests that the students use the brainstorming technique and specify as many birds’ adaptations for flight as possible. A volunteer writes down the ideas on a sheet of paper.

2. The teacher randomly divides the class into groups and distributes different types of feathers to the students. The students’ task is to look carefully at the feathers (observe them) and divide them into three groups:

• feathers that are responsible for the ability to fly;

• feathers that give the bird's body a streamlined shape;

• feathers that retain heat.

3. Students look at the illustration “Bird feather structure” in the abstract and check if they have correctly divided the feathers received from the teacher. They justify their decisions using the names of feathers.

4. Students draw and describe the observed feathers. They check how the vane, exposed to the movements of the bird's body and to the air currents, maintains the surface compact. They explain the role of the rachis.

5. The teacher displays a video entitled “Bird adaptations for flight”. The volunteer reads the students' ideas of birds’ adaptations for flight noted during the brainstorming. Students verify them.

6. The teacher displays the video again, stops the frames, and the students write down in their notebooks the features of the birds’ body that are results of their adaptation for flight.

Summary

1. Students do interactive exercise no. 1. The teacher helps the students by asking them leading questions.

2. The teacher asks the students to assess the level of knowledge they have acquired during the classes with the use of table tents. The teacher explains any doubts that students may have.

3. The teacher asks the students to look at the questions written on the board at the beginning of the classes. The teacher asks them to cross out the questions they have received answers to during the classes.

Homework

Students perform the following task: “In winter, the tit must eat as much food as it weighs. Explain how this relates to homeothermy”.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Birds

Birds are warm‑blooded vertebrates. They maintain a relatively constant body temperature, largely independent of the temperature of the surrounding environment. The high body temperature of the birds (41‑42°C) is the result of:

• a high rate of cell metabolism; to maintain this rate, birds eat large amounts of food and use large amounts of oxygen as well as convert a large part of the energy contained in food into heat;

• the presence of adipose tissue and feathers, which protect against heat loss;

• the ability of cooling down the body by evaporating water (panting) and behaving in a way which prevents overheating and chilling of the organism.

Thanks to the development of homeothermy, the birds were able to live in all types of ecosystems on all continents. Some of them, like penguins and petrels, inhabit even the Antarctic coastline.

The most characteristic feature of birds are wings. The wings are covered with feathers, which give them a streamlined (aerodynamic) shape and increase their surface during flight.

The birds’ feathers are divided into down feathers and pennaceous feathers (vanned feathers) – coverts, remiges and rectrices. Down feathers together with the air between them form a layer that protects the bird from cold. Coverts cover the down and hinder the exchange of heat with the environment. Remiges overgrow the feathers and form their load‑bearing surface. Similarly to remiges, rectrices are arranged on the tail in a fan‑like fashion on the tail and are used to control the flight, maintain the balance and slow down the speed during landing.

Pennaceous feathers are composed of a shaft and a vane. The part of the shaft in the skin is the calamus; the remaining part, covered with a vane is the rachis. The vane is made up of barbs from which barbules equipped with hooklets go sideways. Hooklets overlap to form a light, compact and flexible surface of the vane.

In order to the ability to fly, the birds must be light. Therefore their bones are pneumatised – have spaces filled with air inside. The forelimbs of birds are in the form of feather‑covered wings. In order to the ability to fly, the birds need strong muscles to move their wings. They are attached to a wide keel on the sternum. The skull of the bird has no teeth which would burden the head during the flight.

In birds, gas exchange takes place in lungs made up of a large number of thin tubes intertwined with each other. As a result, they have a large gas exchange surface. This is important because flying requires a great deal of energy, which is released in the presence of oxygen. Air is stored in air sacs. These are thick‑walled tanks filled with air and connected to the bronchi. They reduce the specific weight of the bird.

Lung ventilation can occur in two ways. During walking or resting, the air is pumped into the lungs thanks to the rhythmic movement of the chest, caused by the contraction of the intercostal muscles. During the flight, the chest is stiffened, as it provides support for the muscles moving the wings. When the bird raises its wings, the inhale takes place and the air enters the lungs and the air sacs through the airways. When the wings are lowered, the exhale takes place. Then the used air escapes from the lungs and the air stored in the air sacs is sucked into the lungs, oxygenating the blood. This mechanism is called double respiration, because oxygen‑rich air flows through the lungs of the bird twice, both when it is inhaled and when it is exhaled.

Birds, like reptiles, are amniotes. The embryo of the bird develops from an embryonic disc which forms on the surface of the yolk constituting the source of food for the embryo. The egg yolk is kept in place by the protein structures known as strands. The highly hydrated protein protects the germ from drying out and absorbs shocks. The pores in the egg shell and the air chamber allow for gas exchange. The parchment membranes and the calcareous shell protect the egg from mechanical damages. As the embryo develops, the shell becomes thinner, as the calcium it contains is gradually built into the bone.

Bird nestlings are usually altricial species that hatch out unfledged, blind and dependent on their parents for a long time. If the nestling after hatching is covered with down feathers and has open eyes, can immediately leave the nest and follow its mother, it is called precocial species. This is the case in hens, ducks, ostriches.

Chaffinch occurs in agricultural and urbanized areas. It inhabits all types of forests, parks, cemeteries and even house gardens and parcels. It feeds on seeds of herbaceous plants, trees and shrubs, as well as fruits and grains and sometimes tree buds. It can also eat insects and arachnids from tree branches.

Eurasian eagle‑owl is the largest Polish owl. It hunts at night, guided by its hearing and eyesight. Feathers around the eyes and the beak create a facial disc, an antenna that concentrates sounds and guides them to the ear. Eurasian eagle‑owl has a massive silhouette, a large round head, orange eyes and characteristic clusters of feathers resembling ears. It inhabits vast primary forest areas. It hunts for medium sized birds and mammals, sometimes also insects.

The fastest bird is the peregrine falcon, which can reach speeds of up to 300 km/h when nose‑diving down. It is characterized by a large, bulky and strong silhouette with long, sharp‑ended wings and a massive head. It hunts for small vertebrates during the day, mainly birds and mammals. It inhabits all continents, most often river valleys, mountain areas and forests close to water reservoirs. It can also be found in urban areas.

• Birds are warm‑blooded vertebrates that can fly (or, as in the case of ostriches, their ancestors could) and inhabit all the world's ecosystems.

• The birds' adaptations to flight include, among others, covering with feathers, a forelimb transformed into a wing, the presence of a keel on sternum, a light skeleton, and the presence of air sacs.

• The shape of the bird's beak depends on the type of food it feeds and how it is obtained.

• The structure of the bird's hindlimbs depends on the bird's lifestyle and the inhabited environment.

• Double respiration in birds is due to the presence of air sacs.

• Birds are oviparous, characterised by internal fertilisation.

• Birds are amniotes, their young develop in eggs and are surrounded by foetal membranes which provide optimal conditions for their development.