Page 143 - Science Course 1 (Book 1)

Mo4-L6a: What is Alternation of Generations?

Alternation of Generations

Meiosis occurs in certain cells in the reproductive
structures of a diploid plant.
The daughter cells produced from haploid structures
are called spores.

Haploid Gametophyte
(n)
Archegonium
Individual Sperm
(sporophyte) Spore
Archegonium
Key Concept n n n
What is Alternation of Generations? n Spores

What is alteration of generations in plants?
Meiosis Fertilizations

2n Spore mother Zygote
cell 2n
Embryo
Sporangia 2n

Sporophyte
Diploid (2n)

Spores grow by mitosis and cell division and form
the haploid generation of a plant.

Certain reproductive cells of the haploid generation
produce haploid sperm or eggs by mitosis and cell
division.

Fertilization takes place when a sperm and an egg
fuse and form a diploid zygote.

SUMMARY

What is Alternation of Generations?

The life cycle of a plant includes an alternation of generations.

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