1. Alternation of Generations
Plant Reproduction
Alternation of Generations

2. Alternation of Generations – the way in which all land plants and many algae undergo sexual reproduction

3. First, let’s talk about animals…

6. Plants are similar New plants are formed by the union of sex cells
Each sex cell carries half the hereditary material to create a new plant
But, plants can carry both male and female sex cell structures

7. Plant life cycle 2 distinct stages, or “generations”, of plants
Adult generation produces spores, and is a sporophyte
Immature “spore” generation are called gametophytes. These produce sex cells, called gametes

8. Soooooo………. Plant Life Cycle
Sporophyte chromosomes exist in its cells in pairs – denoted as “2n”
Full set of chromosomes in a cell is also referred to as being diploid
Gametophyte chromosomes exist in its cells as singles – denoted as “1n”
Half set of chromosomes = haploid
Soooooo……….

9. And the cycle begins again…
Plant Life Cycle
Most of a plant’s life cycle is spent with a full set of chromosomes (as a sporophyte)
However, plants live one entire stage, or “generation”, of life with a single set of chromosomes (as a gametophyte)
When the sex cells, or gametes, produced by gametophytes come together, fertilization occurs
And the cycle begins again…