Reproductive Strategies
-Gametes must move from one organism to another
-Algae release unprotected gametes into the water
-Gametes are single celled structures that cannot survive exposure to air for very long
-First land plants had layer of thick-walled cells around reproductive parts to keep from drying out, could only release gametes when film of water covered plant
-Mosses, ferns, and their relatives still depend on external water in order to reproduce
-Other plants consist of tiny waterproof structures that are carried to female plants not by water but by wind, insect or animals, such as pollen
-After fertilization, zygote develops inside a protective, waterproof coat forming the seed
-seed can be dormant for long periods of time to protect against drought and freezing which makes seed-bearing plants more widespread and diverse than seedless plants
-Algae release unprotected gametes into the water
-Gametes are single celled structures that cannot survive exposure to air for very long
-First land plants had layer of thick-walled cells around reproductive parts to keep from drying out, could only release gametes when film of water covered plant
-Mosses, ferns, and their relatives still depend on external water in order to reproduce
-Other plants consist of tiny waterproof structures that are carried to female plants not by water but by wind, insect or animals, such as pollen
-After fertilization, zygote develops inside a protective, waterproof coat forming the seed
-seed can be dormant for long periods of time to protect against drought and freezing which makes seed-bearing plants more widespread and diverse than seedless plants
Alternation of Generations
-Plant life cycle has two generations, alternating between haploid and diploid stages
-Diploid generation is called the sporophyte
-Through meiosis sporophytes produces haploid spores, develop without fertilization
-Haploid spore grows into plant body called gametophyte
-Gametophyes produce male and female gametes, fuse at fertilization, develop into another sporophyte
-Cycle repeats itself
-All plant life cycles include sprorphyte and gametophyte however one is dominant in certain plants
-Non-vascular plants the dominant stage is the gameophyte
-Vascular plants the sporophyte is dominant
-Flowering plants the gametophyte is reduced to small group of cells entirely dependent on sporophyte
-Diploid generation is called the sporophyte
-Through meiosis sporophytes produces haploid spores, develop without fertilization
-Haploid spore grows into plant body called gametophyte
-Gametophyes produce male and female gametes, fuse at fertilization, develop into another sporophyte
-Cycle repeats itself
-All plant life cycles include sprorphyte and gametophyte however one is dominant in certain plants
-Non-vascular plants the dominant stage is the gameophyte
-Vascular plants the sporophyte is dominant
-Flowering plants the gametophyte is reduced to small group of cells entirely dependent on sporophyte