1. CHARACTERISTICS OF PLANTS:
Eukaryotic Cells
Autotrophic and Multicellular
Cell Walls Contain Cellulose
Alternation of Generation
Embryonic Development

2. CHALLENGES FACED BY PLANTS
FOR LIFE ON LAND
Obtaining enough water
Transporting water and dissolved
substances to other parts of the plant body and transporting the products of photosynthesis to other parts of the plant that don't conduct photosynthesis

3. Preventing excessive loss of water
by evaporation
Maintaining an extensive moist
surface for gas exchange
Supporting a large plant body against
gravity
Carrying out reproduction when there
is little water

4. Lastly, withstanding the extreme
fluctuations in temperature,
humidity, wind, and light which
are moderated in water due to
its high heat capacity

5. More than 280,000 species of plants inhabit Earth today.
Land plants (including the sea grasses) evolved from a certain green algae, called charophytes

6. There are four main groups of land plants:
Bryophytes
Pteridophytes
Gymnosperms
Angiosperms – 90% of all
plants

7. Representatives of the Four Major Groups of Plants

8. There are four great episodes in the evolution of land plants:
the origin of bryophytes from algal ancestors
the origin and diversification of vascular plants
the origin of seeds
the evolution of flowers

10. Some Highlights of Plant Evolution
140 mya
360 mya
420 mya
475 mya

11. Alternation of Generations: a Generalized Scheme

12. Reduction in the Size of the Gametophyte

13. Phylum Bryophyta
Liverwort
Liverwort
Hornwort
Moss

14. Moss with Sporophytes
Gametophytes

15. Liverwort, Marchantia
Antheridia Archegonia

16. Hornwort – a Characteristic Bryophyte

17. Pteridophytes
Club
Moss
Whisk Fern
Horsetail
Fern

18. Whisk Fern, Psilotum

19. Lycophyte
Club
Moss

20. Club Moss in Olympic National
Forest – WA State

21. Club Moss in Olympic National
Forest – WA State

22. Club Moss, Lycopodium

23. Horsetail

24. Fern sporophyll, a leaf specialized for spore production

25. Fern Sori

26. The evolution of the seed in an ancestor common to gymnosperms and angiosperms facilitated reproduction on land.
The first seed plants evolved about 360 million years ago, near the end of the Devonian Period.

27. The early seed plants gave rise to the diversity of present-day gymnosperms, including conifers.
A seed consists of a plant embryo packaged along with a food supply within a protective coat.

28. Three variations on Gametophyte/Sporophyte Relationships

29. The Gingko (biloba) tree is a “living fossil” and has been on
Phylum Ginkgophyta
The Gingko (biloba) tree
is a “living fossil”
and has been on
the earth virtually
unchanged for
at least 150 million years. There is one
on our campus
of Esperanza just
outside Mr. Pietsch’s room.

30. Seeds
Female Gingko

31. The Ginkgo Tree

32. Male
Female

33. Phylum Cycadophyta: Sago Palm/Cycad

34. Sago Palm or
Cycad,
a gymnosperm

35. Sago Palm or Cycad Cones
Figure 24.19

36. Phylum Gnetophyta: Welwitschia

37. Phylum Gnetophyta:
Ephedra

38. Ephedra
Figure 24.21

39. Phylum
Coniferophyta:
Douglas
Fir

40. These are
male cones
on a pine
tree.

41. Female Pine Cone
Male Pine
Cones

42. This picture was taken in Sequoia National Park in Central California.
One sequoia tree, nicknamed the “General
Sherman Tree” is the heaviest/largest tree in the world. It is over 2300 years old and weighs
over 1300 tons.

43. This picture is of
“The Lone Cypress”
taken on the 17
mile drive on the
Monterey Peninsula.
It is one of the most commonly photographed trees in the
world.

44. This picture is of the Bristlecone Pine Tree which is the oldest tree in
the world – over
4700 years old.
“Methusaleh” as the oldest tree is called is located in the White Mountains of California.

45. The great majority (90%)of modern-day plant species are flowering plants, or angiosperms.
Flowers evolved in the early Cretaceous period, about 140 million years ago.
A flower is a complex reproductive structure that bears seeds within protective chambers called ovaries.

46. Representatives of Major Angiosperm Clades

47. Figure Flower-pollinator relationships: Scottish broom flower and honeybee (left), hummingbird (top right), baobab tree and bat (bottom right)

48. Generalized Flower Structure

49. Table 30.2 A Sampling of Medicines Derived from Plants

50. Leaves of Vascular Plants

51. Moss (Polytrichum) Life Cycle

52. Fern Life Cycle

53. Pine Life Cycle

54. Angiosperm Life Cycle