1. Plant Diversity
Ch 20-22

2. Where did plants come from?
Plants evolved from protists called algae.
Algae are photosynthetic and they have cell walls, but they are NOT plants
Live in water (prevents drying out, carries sperm to eggs, can support weight)
Algae that were able to withstand dry spells evolved into plants

3. Algae

4. How come plants can live on land?
Adaptations!
Retaining moisture
Transport water & nutrients
Grow upright
Reproduce without free-flowing water

5. How come plants can live on land?
Retaining Moisture
Surface of plant is covered with a waxy coat called a cuticle that holds in water.
Pores in the cuticle called stomata allow air to move in and out
Stomata can close to prevent water loss

6. How come plants can live on land?
Transporting Water & Nutrients
Vascular system is made of specialized tissues that bring water & minerals from the soil from the roots & disperse sugars down from the leaves
Allows plants to grow tall

7. How come plants can live on land?
Growing Upright
Height is limited by ability to support weight
Storage for vascular system
Support comes from a tissue called lignin which hardens the cell walls

8. How come plants can live on land?
Reproducing Without Free-Flowing Water
Pollen grains are 2 celled structures that will divide to form sperm
Can be carried by wind or animals

9. How come plants can live on land?
Reproducing Without Free-Flowing Water
Seeds are storage units for plant embryos.
Hard coat protects it from drying out
Contains nutrients

10. Plant Classification Seedless & Non-Vascular
Grow close to ground/on surfaces where they can absorb water & nutrients directly
Rely on free-standing water for sperm dispersal
Mosses

11. Plant Classification Seedless with Vascular
Have vascular systems, allowing them to grow tall
Still rely on water to spread sperm cells
Ferns

12. Plant Classification Seeds - Gymnosperm
Plant whose seeds are NOT enclosed in fruit
Most gymnosperms carry their seeds inside cones
Conifers - pine trees

13. Plant Classification Seeds - Angiosperm
Plant whose seeds are enclosed in fruit
Also have flowers which are the reproductive structures
Fruits are a flower’s mature ovary

14. Flowering Plants Pollination Wind pollination
Animal pollination is most effective
Allows sperm cells to travel to different flowers - genetic diversity!

15. Flowering Plants Seed Dispersal
“Fruit” refers to a flower’s mature ovary - not necessarily what we know as fruit
Anything that protects the seed
Peanut shells, fibers that help catch the wind, burrs

16. Flowering Plants
Seed dispersal - Can be eaten by animals and passed, carried by wind, carried by water
Brought to new environment
Germination - Embryo breaks through seed coat and begins to grow

17. Flowering Plants Flowering plants can be classified by seed type
Cotyledon - an embryonic leaf inside a seed

18. Flowering Plants Monocots
Flowering plant whose embryos only have one cotyledon
Other common characteristics: Parallel veins, flower parts occur in threes, scattered vascular tissue

19. Flowering Plants Dicots
Flowering plant whose embryos have two cotyledons
Other common characteristics: Netlike veins, flower parts in fours or fives, ringed vascular tissue

20. Flowering Plants

21. Flowering Plants
Flowering plants can also be classified by whether or not they have wood
Wood is a fibrous material made up of dead cells that are part of the vascular system of some plants.

22. Flowering Plants
Woody Stem Herbaceous Stem

23. Plant Tissue
Three kinds of plant tissues that perform different functions
Dermal - Tissue that secretes a waxy substance that forms the cuticle, or dead lignin cells that form bark
Purpose: Protects plant

24. Plant Tissue Ground - Makes up the inside of the plant.
Purpose: Nutrient storage, support, chloroplasts

25. Plant Tissue Vascular Tissue - Innermost part of plant
Purpose: Transports water and nutrients

26. Plant Structures - Roots & Stems
Roots anchor plants to ground
Absorb and transport nutrients and water
Fibrous roots and taproots

27. Plant Structures - Roots & Stems
Stems support plant and transport water and nutrients through the vascular tissue
Can grow above OR underground

28. Plant Structures - Leaves
Leaves grow out from plant stem
Provide a large surface area for photosynthesis
Many leaf adaptations include thick waxy leaves, pine needles, & cactus spines

29. Plant Structures - Flowers
Flowers house reproductive organs
Sepals are modified leaves that protect a developing flower
The bud

30. Plant Structures - Flowers
Petals are modified leaves that are brightly colored to attract pollinators

31. Plant Structures - Flowers
The stamen is the male reproductive organ
The stamen supports stalks where the anthers produce pollen

32. Plant Structures - Flowers
Innermost structure of flower is the carpel, which are the female structures
The ovary is at the base of the flower
Where eggs are produced and stored

33. Plant Reproduction
When a female egg is fertilized by a pollen grain, the egg becomes a seed.
While the seed is developing, the ovary (fruit) begins to mature to serve as protection for the seed

34. Plant Reproduction
When the fruit matures, the seeds can be dispersed and germination can begin again!

35. Why learn about plants? Food (duh) Shelter Clothing Medicines
Wood to build
Clothing
Cotton
Medicines
Treatments for many diseases