【PEP】Junior High Biology · Grade 8 Vol. 2: Continuity of Life — Classification and Significance of Reproduction Methods

The Relay of Life: Reproduction & Development

Life is an endless relay race. Organisms pass the torch throughReproductionandDevelopment, ensuring the continuity of life across generations in the biosphere. At its core areHereditywith its stability, andVariationwith its diversity — the fundamental driving force of evolution.

Two Pathways of Reproduction

Sexual Reproduction: Male and female gametes fuse to form aZygote, which then develops into a new individual. For example, when plants flower and bear fruit, the offspring inherit traits from both parents, giving them greater adaptability.
Asexual Reproduction: A new individual is produced directly from a single parent without the fusion of gametes. Examples include bacterial fission and plant division. This allows for rapid "cloning" of desirable traits in stable environments.

Deep Dive

Why is development considered a bridge to evolution? It is not merely the growth of an individual from small to large, but a core expression of adaptive strategies — such as the transition from aquatic to terrestrial life.

QUESTION 1

What is the starting point of individual development in frogs? What does this tell us about the impact of environmental change on amphibian reproduction? What might cause the appearance of deformed frogs in certain regions?

The starting point is the zygote; environmental degradation can impede reproduction; deformities may result from water pollution or genetic mutations.

The starting point is the tadpole; environmental change has no effect; deformities are a result of natural evolution.

The starting point is the egg cell; environmental change promotes reproduction; deformities are caused by abundant food.

QUESTION 2

True or False: When growing chrysanthemums and aloe vera, a single plant often becomes a clump. If you divide it into many individual plants, this method of propagation is a form of asexual reproduction.

✓ True

✗ False

QUESTION 3

What is the essential difference between sexual and asexual reproduction?

The size of the offspring

Whether gametes are produced

Whether male and female gametes fuse together

QUESTION 4

In the sexual reproduction of angiosperms, which structure develops into the "embryo," the main part of the seed?

Ovary wall

Zygote

Pollen tube

QUESTION 5

Which of the following is an advantage of asexual reproduction?

Produces offspring with genetic traits from both parents

Maintains desirable parental traits and allows rapid reproduction

Increases the potential for variation in a species