"Reproduction and Development of Birds" Biological Reproduction and Development PPT Courseware 3

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"Reproduction and Development of Birds" Biological Reproduction and Development PPT Courseware 3

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.

Early birds: ducks, geese, geese, chickens

Late birds: domestic pigeons, swallows, sparrows, cuckoos

"The reproduction and development process of birds generally goes through stages such as courtship, mating, nest building, egg laying, egg incubation, and brood raising." Are there any exceptions? Are there exceptions for all stages?

Some birds do not build nests, incubate eggs, or raise chicks, such as cuckoos. Cuckoos lay their eggs in the nests of other birds, such as thrushes, crows, thrushes, and warblers, and these birds incubate the eggs and raise their chicks.

No matter what the characteristics of the reproduction and development of various birds are, in the process of reproduction and development, birds must have courtship, mating, egg-laying and other behaviors.

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.

Please think about and discuss?

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

What are the characteristics of the blastoderm? Which part of the egg will develop into a chick? Will all eggs develop into chicks in the future?

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.

What are the characteristics of the blastoderm? Which part of the egg will develop into a chick? Will all eggs develop into chicks in the future?

The blastoderm contains the nucleus, which is an important structure that constitutes the egg cell. The formation of the embryo begins here and will develop into a chick in the future. Only fertilized eggs can develop into chicks. The blastoderm of unfertilized eggs is light in color and small; the embryonic disk of fertilized eggs is dark in color and slightly larger. The blastoderm is the site of embryonic development, and under suitable conditions the embryo develops into a chick.

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

The blastoderm, yolk and vitelline membrane tightly wrapped around the yolk constitute the egg cell.

quick practice

1. "A few early orioles are vying for warmth in the trees, but the new swallows are pecking at the spring mud." What reproductive behavior of birds does this poem describe?

2. Answer according to the picture:

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

2. Containing the nucleus, the site of embryonic development 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.

think about it

The fertilized bird egg begins to develop in the female bird, but the development of the bird egg stops after it is laid. The reason is ()

A.Have sunlight B.Have air

C. Temperature is too low D. Humidity is too low

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Update Time: 2024-07-04

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

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