Chapter 26
Seed Plants
By Boundless
The evolution of seeds allowed plants to reproduce independently of water; pollen allows them to disperse their gametes great distances.
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Seed ferns gave rise to the gymnosperms during the Devonian Period, allowing them to adapt to dry conditions.
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Angiosperms, which evolved in the Cretaceous period, are a diverse group of plants which protect their seeds within an ovary called a fruit.
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Gymnosperms are seed plants that have evolved cones to carry their reproductive structures.
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Conifers are monoecious plants that produce both male and female cones, each making the necessary gametes used for fertilization.
![Thumbnail](../../../../../figures.boundless-cdn.com/19236/square/figure-26-02-04.jpeg)
Gymnosperms are a diverse group of plants the protect their seeds with cones and do not produce flowers or fruits.
![Thumbnail](../../../../../figures.boundless-cdn.com/19238/square/figure-26-03-02.jpeg)
Flowers are modified leaves containing the reproductive organs of angiospems; their pollination is usually accomplished by animals or wind.
![Thumbnail](../../../../../figures.boundless-cdn.com/20661/square/fruits-from-barro-colorado.jpg)
A fertilized, fully grown, and ripened ovary containing a seed forms what we know as fruit, important seed dispersal agents for plants.
![Thumbnail](../../../../../figures.boundless-cdn.com/19239/square/figure-26-03-03.jpg)
Angiosperms are seed-producing plants that generate male and female gametophytes, which allow them to carry out double fertilization.
![Thumbnail](../../../../../figures.boundless-cdn.com/19241/square/figure-26-03-05.jpeg)
Angiosperm diversity is divided into two main groups, monocot and dicots, based primarily on the number of cotyledons they possess.
![Thumbnail](../../../../../figures.boundless-cdn.com/19243/square/figure-26-04-02.jpeg)
The diversity of plants can be attributed to pollination and herbivory, both examples of coevolution between animals and plants.
![Thumbnail](../../../../../figures.boundless-cdn.com/19244/square/figure-26-04-03abcd.jpeg)
Human life has become dependent on plants for the qualities and developments that they provide, which include medicine and food production.
![Thumbnail](../../../../../figures.boundless-cdn.com/20619/square/snra-logging.jpeg)
Plant biodiversity, vital to ecosystems, food crops, and medicine production, is threatened by habitat destruction and species extinction.