Overview Of Plants

1
Overview OfPlants

• Chapter 30
• Section 1

2
Diversity Of Plants

• There are many sizes and shapes of plants, some
  are very small measuring less then 1mm in width.
• Also some can grow to astonishing sizes and live
  for nearly 5000 years.

3
Adapting to Land

• For 3 Billon years plants flourished in the
  oceans but haven't spread onto the land Because
  the ozone layer hadn't been formed yet, and
  without the ozone layer the ultraviolet radiation
  could harm organisms.
• Eventually small shrub like Plants managed to
  spread onto the shores and grow in the mud.

4
Land vs water

• Growing on land gave plants several advantages
  over plants in the water.
• Increased sunlight
• Increases carbon dioxide supply
• Larger supply od inorganic nutrients

• There were also some new problems the plants
  found
• Living on land made the plants easier to dry out
• Gravity was also a problem plants faced as the
  water would normally support them in the water.

5
Adapting to land

• One adaptation plants made to live on land was a
  cuticle(a waxy covering on plant surfaces to
  prevent moisture loss
• This cuticle would also interfere with the supply
  of CO2 so the plants had small openings on their
  surfaces called stomata
• Stomata allow the exchange of carbon dioxide and
  oxygen

6
Reproduction

• Land plants produced seeds and spores to protect
  to gametes
• Seeds-is an embryo with a protective coat, and
  also contains an endosperm to nourish the the the
  future plant.
• Spores-Are a haploid reproductive cell surrounded
  by a hard outer wall.

7
Distribution of essentials Nutrients

• Most species of plants evolved vascular tissues
  to transport water and nutrients around the plant
• Xylem-carries water and inorganic nutrients from
  the roots to the stems and leaves
• Phloem-Carries the organic compounds like
  carbohydrates and some inorganic nutrients
  wherever the plant needs it.

8
Vascular tissues other Functions

• Vascular tissues also help to support the plant.
• Woody tissue is made of several layers of xylem
  usually located in the center of the stems
• Nonwoody plants are called herbaceous because
  they have soft normally green stems and usually
  flexible

9
Classification of Plants

• There are 12 phyla of plants containing ,
  nonvascular, vascular seedless, and vascular
  plants.
• Vascular plants have actual vascular stems,
  roots, and leaves
• Nonvascular plants do not have the vascular
  tissue system to transport nutrients.

10
Classification cont

• Seed plants are plants that use seeds to reproduce

11
Plants of the past

• The Fossil record is incomplete so scientists do
  not know for sure where or what plants evolved
  from but it is believed the they evolved from
  green algae.
• Green algae and plants have the same
  photosynthetic pigments
• They both have cell walls made of cellulose
• They both store energy as starch.

12
Alternating life cycles

• All plants have 2 phases in their life cycle.
• The first phase consists of a Diploid Sporophyte
  plant that produces spores.
• The second phase consists of a haploid
  gametophyte plant that produces eggs and sperm.

13
Plant Cycle

• In the phase of gametophyte the egg and sperm
  gametes are formed.
• When the sperm fertilizes an egg cell it produces
  a zygote and that is where the diploid part of
  the life cycle begins.
• The zygote then divides and produces a sporophyte
  plant.
• The plant will then create spores which will be
  released unless it is a seed plant then the
  spores will be retained.

14
The End