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Gymnosperms

Gymnosperms

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Gymnosperms

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  1. Gymnosperms

  2. Gymnosperms • Gymnosperms are plants that produce naked seeds – or seeds that are not covered by a protective fruit.

  3. Gymnosperms • Every gymnosperm produces naked seeds (they are not surrounded by a protective fruit) • Many gymnosperms have needle-like or scalelike leaves, and deep-growing root systems.

  4. Gymnosperms • Gymnosperms are the oldest seed plants • They first appeared on Earth about 360 million years ago • There were many more types of gymnosperms in the past. Today, only four groups of gymnosperms exist.

  5. Types of Gymnosperms - Cycads • About 175 million years ago, the majority of plants were cycads. • Today, cycads grow mainly in tropical and subtropical areas • They look like palm trees with cones.

  6. Types of Gymnosperms - Conifers • Conifers, or cone bearing plants, are the largest and most diverse group today. • Most conifers keep their leaves year round (pines, junipers, and evergreens)

  7. Types of Gymnosperms - Ginkgoes • Ginkgoes also grew hundreds of millions of years ago, but today only one species still exists.

  8. Types of Gymnosperms - Gnetophytes • Gnetophytes live in hot deserts and in tropical rain forests. • Some are trees, some are shrubs, others are vines.

  9. Reproduction in Gymnosperms • Most gymnosperms have reproductive structures called cones • There are both female and male cones – usually one plant produces both types of cones. • In some plants, individual plants produce each type.

  10. Reproduction in Gymnosperms • 1) Pollen falls from a male cone onto a female cone • 2) Asperm cell and an egg cell join together (fertilization) in an ovule on the female cone • 3) The seed develops on the scale of the female cone.

  11. Reproduction in Gymnosperms Male Pine Cone Female Pine Cone

  12. Gymnosperms in Everyday Life • Paper and other products, such as lumber used to build homes, come from conifers. • Because conifers are so useful to humans, they are grown in large, managed forests in many regions of the US.