The Diversity of Plants

1
The Diversity of Plants

• Unit 7
• Chapter 22

2
Nonvascular plant habitat

• Near water source

3
Nonvascular plant size

• Because nonvascular plants do not have xylem and
  phloem, they depend on diffusion to get water and
  nutrients to each cell.
• Consequently, nonvascular plants cannot be large
  because cells farther away from a water source
  would die..

4
Rhizoids

• Structures that are similar to roots that anchors
  and absorbs nutrients for the nonvascular plant

5
Alternation of generation life cycle

• Antheridium male structure that produces sperm
• Archegonium female structure that produces egg
• Sperm egg ? zygote

6
Alternation of generation life cycle

• The zygote grows into a plant structure called a
  sporophyte.
• The sporophyte produces spores by meiosis.
• The spores grow into a plant structure called a
  gametophyte.

7
Alternation of generation life cycle

• The gametophytes are either male or female.
• Male antheridium
• Female archegonium

8
Prothallus

• The fern gametophyte body that develops male
  (antheridia) or female (archegonia) reproductive
  structures

9
Sorus on fronds

• Structures underneath the frond leaflets of fern
  plants are called sorus.
• These structures produce spores that germinate to
  form the prothallus.

10
Cones

• The structures that bear the male and female
  reproductive parts in gymnosperms (exposed seed,
  vascular plants) that produce sperm and egg are
  called cones.
• Most associate cones with pine trees.

Large cycad cone
11
Pollen grains

• The male gametophytes of seeded plants are pollen
  grain, which are sperm and nutrients packaged
  within a protective coat.
• These structures carry sperm cells to an egg.

Pine pollen grain with air pockets to help the
structure stay afloat in the air
12
Pollen grains in flowering plants

• Flowering plants produce pollen grains within the
  male reproductive structures on flowers.

13
Ovule in flowering plants

• The ovule is a protected structure that produces
  eggs.

14
Seed development in flowering plants

• Sperm egg ? zygote
• The zygote develops into an embryo found within a
  seed.
• The seed may have one or two structures
  (cotyledons) that store food.
• Monocot plants that make one cotyledon seeds
• Dicot plants that make two cotyledon seeds

15
Dicot seed germination (ex bean)
16
Fruit

• Only plants that produce flowers produce fruits.
• The fruit is a covering that either helps the
  seed fly through the air or entices animals to
  eat the fruit to disperse the seeds.

17
Evergreen vs. deciduous plants

• Evergreen plants that retain leaves over winter
• Deciduous plants that drop leaves over winter

evergreen
deciduous
18
Annual plants

• produce seeds that survive harsh winters, but
  parent plant dies after one year

19
Biennial plants

• Life cycle lasts two generations (years)
• Year 1 develop root system, storing sugars
• Year 2 flowers, fruits, and form seeds

20
Perennial plants

• Plants that live for multiple years, continuously
  producing viable seeds
• Usually during winter, leaves drop but the wood
  stems survive.