1. Plants with Seeds
Chapter 22-4, 22-5

2. Seed plants There are two groups of seed plants:
Gymnosperms ~ seeds are found on the surfaces of cones
Angiosperms ~ seeds are within a layer of tissue that protects the seed

3. Adaptations of Seed Plants
Unlike mosses and ferns, seed plants do not require water for fertilization of gametes
ADAPTATIONS that allow seed plants to reproduce without water:
1) flowers or cones
2) transfer of sperm by pollination
3) protection of embryos in seeds

4. Adaptation #1: Cones and Flowers
Cones and flowers are sporophyte structures in which the gametophytes of seed plants grow
Cones = seed-bearing structures of gymnosperms
Flowers = seed-bearing structures of angiosperms

5. Adaptation #2: Pollen
In seed plants, the male gametophyte is contained in a pollen grain
The pollen grain is carried to the female reproductive structure by wind, insects or small animals  pollination

6. Pollination
Pollination can occur through biotic and abiotic means (wind, water, birds, insects, etc…)
Morphological characteristics of flowers attract specific pollinators

7. Insects – the Great Pollinators
Conventional spectrum
What bees see 

8. Bats as Pollinators

9. Adaptation #3: Seeds Seed = embryo of the plant (diploid)
Seed has a seed coat (protective covering) and food supply that gives nutrients to the embryo
The embryo develops from the zygote after fertilization

10. Development of Seeds Function of seed structures:
Endosperm Nutrition for embryo
Endosperm Cotyledon(s)
Cotyledons Nutrition for embryo
*Endosperm = food storage tissue
*Cotyledons = first leaf or pair of leaves produced by the embryo of a seed plant

11. Overall, what is the function of a seed?
Protects young embryo
Provides nutrition for the developing embryo
Allows dispersal of the embryo over time & space

12. Seed to Seedling

13. Fruits
Fruit. Mature ovary of the a flower that protects dormant seeds and aids their dispersal
Seeds are the product of pollination
Seeds are located within fruits
There are many different types of fruits

14. Fruit Types

15. Seed Dispersal Seeds are highly adapted to dispersal
Examples of morphological characteristics would be buoyancy in fruits (coconut) and “wings” (maple seeds)

16. While others are simply blowing in the wind….

17. Some seeds are dispersed as a result of being eaten and mingling with feces….

18. GYMNOSPERMS: Non-Flowering Seed Producers

19. Transition from Ferns to Land Plants Medullosa – the seed fern

20. Gymnosperms began to dominate landscapes as climates became drier at the end of the Paleozoic era 245 mya
Gymnosperms appear in the fossil record much earlier than flowering plants, and they:
Lack enclosed chambers in which seeds develop.
Are grouped into four divisions:
Cycadophyta, Ginkgophyta, Gnetophyta and
Coniferophyta.

21. GYMNOSPERMS:
Plants with seeds that are not enclosed within a fruit, derive their name from the Greek words gymnos (naked) and sperma (seed). In this plant group, the seeds are produced on the open surface of a scale. Unlike flowering plants, the gymnosperms do not form true flowers or fruits. There are four divisions of gymnosperms.
Examples of gymnosperms include cycads, ginkgo, conifers and gnetops.
Kingdom  Plantae - Plants
Subkingdom  Tracheobionta -- Vascular plants
Superdivision  Spermatophyta - Seed plants
Division  Cycadophyta - Cycads
Class  Cycadopsida
Order  Cycadales
Family  Cycadaceae
Genus Cycas- cycads

22. Evolutionary advancements of Gymnosperms over the ferns and allies:
Seeds
Lack of dependence on water for fertilization (air-borne pollen)
Progressively more dominant sporophyte
Life Cycle
In the gymnosperms and the flowering plants, the sporophyte generation is dominant with the gametophyte contained in and dependent on the sporophyte.
Vascular System
They do have a well-developed vascular system of xylem and phloem and have true roots, stems, and leaves.
The vascular tissues are significantly more efficient and effective than the vascular systems of the seedless plants such as the ferns.
Gymnosperms are usually woody plants. The xylem form the wood if a tree and the phloem tissues are part of the bark (along with cork). The formation of wood from secondary growth is the reason that some sporophytes can reach such large sizes.

23. The Cycad – a fernlike gymnosperm. Note the cone, or strobilus
Cycadophyta
Class Cycadopsida
Order Cycadales
Cycadaceae
Cycas sp.
The Gymnosperms
The Cycad – a fernlike gymnosperm.
Note the cone, or strobilus

24. Male cones of Pinus nigra
Unlike the seedless vascular plants, conifers are more prevalent in cooler regions and in desert habitats.
leaf curled to reduce water loss
evolved cold hardiness
Female cones of Pinus nigra

25. The Gymnosperms Gnetophyta
With angiosperm-like broad leaves, but still retaining cones, the Gnetophytes are another very close link to the Angiosperms

26. Welwitschia mirabilis growing in the desert
Ephedra viridis
Female cones
More Gnetophytes!
All bear cones, with naked seeds, which is an adaptation over the ferns, that produced spores
Welwitschia mirabilis growing in the desert

27. The link between gymnosperms and angiosperms (note the fleshy seed)
Ginkgophyta
Ginkgo biloba
The link between gymnosperms and angiosperms (note the fleshy seed)

28. Angiosperms Phylum Anthophyta
Replaced Gymnosperms as the dominant plant type during the Cretaceous Period 60 million years ago
Produce flowers, fruits, and seeds

29. Flowers and Fruits Flowers: Fruits:
Are unique reproductive organs of angiosperms
Contain ovaries which surround and protect the seeds
Thus “angiosperm” = “enclosed seed”
Fruits:
A wall of tissue surrounding the seed
Used to attract animals  dispersal of seeds

30. Can you guess what this is?
The largest seed is produced by the coco de mer, or "double coconut palm", Lodoicea maldivica. The entire fruit may weigh up to 23 kilograms (50 pounds) and usually contains a single seed

31. Flower Morphology

35. Stored food (Endosperm)
Monocot vs. Dicot Seeds
Corn
Bean
Seed coat
Stored food (Endosperm)
Embryo plant

36. Monocot Seeds Endosperm One cotyledon Monocot seeds have: seed coat
coleoptile
radicle

37. Dicot Seeds Dicot seeds have: No endosperm at maturity Two cotyledons
Seed coat
First leaves
Early root
Cotyledon

38. Organization of primary tissues in a young dicot stem (eg. Bean)

39. The primary tissues of a young monocot stem (eg. Corn)

40. Primary tissues of a young dicot root

41. Cross-section through a monocot root

42. General Angiosperm Life Cycle
Germination of Seed
Seed develops into mature sporophyte
Flower grows on sporophyte
Flowers have Stamens and Carpels
Pollen produced in Anther (Stamen)
Female gametophyte produced in Carpel (ovule)
Pollination by various methods
Double fertilization to produce endosperm and embryo
development of seed

43. Plant life spans
Annual: flower plants that complete a life cycle within one growing season
Marigolds, pansies, wheat, cucumbers
Biennials: life cycle complete in two years (flowers in second year)
Parsley, celery, foxglove
Perennials: flowering plants that live for more than two years (most have woody stems)
Asparagus, grasses, palm trees, maple trees

44. Understanding Concepts, page 575
Questions 13-24