"Reproduction and Development of Birds" Biological Reproduction and Development PPT Courseware 5

Description

"Reproduction and Development of Birds" Biological Reproduction and Development PPT Courseware 5

teaching objectives

1. Name the structural characteristics of bird eggs that are suitable for development on land.

2. Describe the reproductive and developmental processes of birds.

3. Pay attention to the relationship between birds and human life by visiting or participating in poultry breeding activities.

Early adult birds: The chicks are fully developed when they hatch. They are covered with dense down feathers, their eyes have been opened, and their legs and feet are strong. After the down feathers dry, they can forage with their parents. Most ground-dwelling birds (such as chickens) and nomadic birds (ducks) are precocious birds.

Late adult birds: The chicks are not fully developed when they emerge from the shell. Their body surface is smooth or slightly covered with sparse velvet. Their eyes cannot be opened and they rely entirely on feeding from their parent birds. They can live independently after completing their development in the nest, such as sparrows. There are also some large and ferocious birds that are late adults.

Observe the structure of chicken eggs

1. Knock out cracks from the blunt end of the egg.

2. Use tweezers to remove the egg shell and outer shell membrane.

3. Cut the inner shell membrane with scissors.

4. Pour the egg white and egg yolk into the petri dish together.

5. Comparative observation.

How to observe eggs

Please think about and discuss?

What are the structures of chicken eggs? What are the functions of egg shell, shell membrane, egg white and yolk?

Which part of the egg will develop into a chick?

What structures in a chicken egg make up the egg cell?

What are the functions of egg shell, shell membrane, egg white and yolk?

egg shell and shell membrane

It protects the eggs. There are many pores on the egg shell for ventilation to ensure that the eggs can exchange gases.

albumin

It protects the embryo, provides moisture and nutrition.

Yolk

It is the main nutritional part of the egg cell, providing nutrients for embryonic development. It is wrapped by the vitelline membrane outside the yolk.

Which part of the egg will develop into a chick?

The blastoderm of the fertilized egg will develop into a chick. The blastoderm contains the nucleus. For unfertilized eggs, the blastoderm is light-colored and small; for fertilized eggs, it is dark-colored and slightly larger. The blastoderm is the site of embryonic development, and under suitable conditions the embryo develops into a chick.

Apply what you learn

1. In winter, we often see empty bird nests with no birds to live in them. What is the reason for this?

These birds migrated south to overwinter

2. If you apply glue to the shell of an egg, can a chick hatch? Try to analyze the reasons.

cannot. Because the glue blocks the small holes in the eggshell, air cannot enter through the small holes, so the chick cannot hatch.

3. Can all the eggs you buy at home hatch chicks? Why?

no. Only fertilized eggs can hatch into chicks

practise

1. Whose new swallow pecks at the spring mud" reflects the nest-building behavior of swallows.

2. Tips: This question is an open question, which trains students' ability to design experiments and allows students to propose ideas and design experiments based on discussion. The experimental protocol below is available for reference.

Prick a small hole in the eggshell with a needle and insert the needle of the syringe into the small hole. Pay attention to the gap between the small hole and the needle, which should be as dense as possible. Then use a syringe to slowly inject air from the small eye to increase the pressure in the eggshell. After a while, you will see little droplets of liquid appear on the surface of the eggshell, indicating that there are small holes in the eggshell.

You can also immerse fresh eggs in warm water at 40°C to 50°C to see if there are small bubbles on the eggshell.

3. According to life experience, the bird eggs listed in the table increase in order. For example, duck eggs are larger than chicken eggs, chicken eggs are larger than pigeon eggs, and the size of ostrich eggs is about several times or even ten times that of other bird eggs. From the hatching time of various bird eggs listed in the table, it can be inferred that the hatching time of bird eggs is related to the size of the eggs.

quick practice

Answer according to the picture:

1. In the picture, ① is _____, ② is ______, ① and ② mainly play the role of ________.

2. Containing the nucleus, the site where the embryo develops is ________.

3. ⑥ in the picture is _______, which can provide _______ for embryonic development.

4. ④ in the picture is _______, and its main function is___________.

5. Generally, it takes ______ days for a fertilized chicken egg to hatch before the chick can hatch out.

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For more information about the PPT courseware "Reproduction and Development of Biological Reproduction and Development of Birds", please click the Reproduction and Development of Biological Ppt ppt Reproduction and Development of Birds ppt tag.

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Update Time: 2024-11-22

This template belongs to biology courseware People's Education Edition Biology for Grade 8, Volume 2 industry PPT template

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