Plant Characteristics and Functions

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Plant Characteristicsand Functions

• 14.1 Classifying Plants

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Evolutionary History

• Celery
• Hornwort

• probable that vascular and non-vascular plants
  have common ancestors with one group of the
  plant-like protists, the green algae

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What they have in common with protists

• both plants and algae use starch as their primary
  food resource, they have cellulose in their cell
  walls, and they use chlorophylls a and b during
  photosynthesis

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Differences

• Protists, which can be unicellular or
  multicellular organisms, have no roots, stems, or
  leaves.
• Algae do not need to develop sophisticated
  systems to transport nutrients and water because
  they live in a medium of water and dissolved
  nutrients.
• The algae absorb nutrients and water directly
  from the external environment, and the material
  diffuses from one cell to another.
• There are no specialized cells to move materials
  within the organism.

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Differences

• members of the plant kingdom live in terrestrial
  environments, from wetlands to deserts and from
  tundra to tropical rain forests.
• They have adapted many ways to survive these
  environments, such as protecting their
  reproductive cells and having more sophisticated
  ways of transporting material both to and from
  their environment and within the plant.

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Non-vascular Plants

• i.e. mosses, liverworts, and hornworts require a
  moist environment for two reasons.
• 1. they cannot reproduce unless a film of
  moisture is available to carry gametes between
  plants
• 2. they lack vascular tissue. They have no system
  of tubes to carry water and dissolved substances
  through the plant.

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Non-vascular Plants

• some appear to have root-like, stem-like, and
  leaf-like parts or structures but they do not
  contain vascular tissue. Meaning
• 1. root-like structures anchor the plant but do
  not absorb water for other parts.
• 2. stem-like structures hold the leaf-like parts
  up to the light, but they cannot transport food
  or water.
• 3. Leaflike structures carry out photosynthesis
  and make food, but the dissolved food must
  diffuse to the other parts of the plant.

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Non-vascular Plants

• Because diffusion is generally a slow process and
  they have no vascular tissue, non-vascular plants
  are restricted in size.

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Uses of non-vascular plants

• play only a minor role in providing food or other
  materials for people.
• Sphagnum moss is used as a base for flower
  arrangements, used as a source of organic
  material for potting and gardening soils
• countries such as Ireland, mined and cut into
  blocks as fuel.
• The princess pine, despite its name, is a
  non-vascular plant that is used in winter flower
  arrangements.

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Vascular Plants

• Extinct Audrey II
• Not extinct Fern

• vascular tissue to transport materials within the
  plant.

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Gymnosperm or Angiosperm?

• All trees living today are either one or the
  other
• The sperm ending indicates that both groups
  grow from seed.
• A seed is a complex multicellular structure that
  contains an embryo and a food supply
• The embryo includes an immature root, an immature
  shoot, and one or two seed leaves or
  cotyledons.
• Inside the seed, the food supply consists of
  nutritive tissue made up of starch, oils, and
  other molecules needed for development of the
  embryo.

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Gymnosperms

• gymnosperms have seeds without a seed coat and
  are attached to the scales of cones.
• gymnosperms have seeds without a seed coat and
  are attached to the scales of cones.

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Gymnosperms

• Many gymnosperms, such as conifers, are adapted
  to thrive in environments with long cold winters
  and low amounts of nutrients in the soil.
• Gymnosperms dominate in large parts of Canada,
  northern Europe, and northern Asia.
• The boreal forest, which is characterized by
  conifers, is the largest biome in Canada. In
  addition, gymnosperms are vital to Canadas
• economy.
• Gymnosperms provides fibre for making paper and
  wood for building materials.

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Angiosperms

• The total number of angiosperm species is far
  greater than the total number of gymnosperm
  species.
• Angiosperms as a group are more diverse in
  structure than gymnosperms. As well, angiosperms
  are so widely distributed around the world that
  their total biomass exceeds that of gymnosperms.
  Thus, angiosperms dominate many parts of the
  biosphere and they are important as a source of
  food for many organisms, including humans.

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Angiosperms

• Angiosperms are also known as flowering plants.
  Flowers are the angiosperms reproductive organs,
  which mature into a seed-containing fruit. The
  extra protection of the surrounding fruit gives
  angiosperm seeds a strong adaptive advantage over
  gymnosperm seeds, which lack an enclosing fruit.
• Once gymnosperm seeds fall or are blown out of
  their cones, they have only a thin cover to
  protect them.
• the fruits of angiosperms are adapted to
  facilitate seed dispersal. Some fruits are tasty
  (like apples), and the seeds are dispersed when
  the fruit is eaten.
• Some are sticky (like burrs) and are dispersed in
  the feathers or fur of animals.
• Others are shaped for flight, such as maple keys,
  and are dispersed by the wind.
• The group of plants we call angiosperms includes
  trees, grasses, vegetables, wildflowers, and
  herbs.
• All angiosperms produce fruits, many of which are
  edible. In addition, the roots, leaves, and stems
  of many angiosperms provide food for humans and
  other animals.

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Angiosperms Monocots and Dicots

• The number of angiosperm species is so large that
  biologists needed a way to group them for study
  purposes.
• They found that all angiosperm seeds have either
  one or two (never more) embryonic seed leaves, or
  cotyledons, inside the seed, and agreed to use
  this difference as a basis for classification.
• The two major angiosperm classes are the
  monocots, which have one cotyledon, and the
  dicots, which have two cotyledons.

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Monocots

• About 10 of all monocots have woody (tough and
  rigid) stems. Examples of woody monocots include
  palms and bamboos.
• grown for ornamental purposes in Canada, but only
  where the climate is mild.
• Most woody monocots grow in warmer climates and
  are sources of food such as dates, coconuts,
  bananas, palm oil, and sugar.
• Sugar cane, a woody monocot, is a type of grass.
• Few monocots are suitable to use as building
  materials. However, the hollow stems of bamboo
  can be used for buidling
• Bamboo shoots are used as food by humans and by
  giant pandas

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Monocots as food

• Two monocots, bananas and their near relatives,
  plantains, are a major source of carbohydrates
  for many of the worlds people.
• During the 1980s, agronomists feared that a
  fungal infection would wipe out these important
  food plants.
• They were able to develop a new disease-resistant
  banana variety.
• This proved to be much more difficult than
  developing a new wheat variety, for instance,
  because cultivated bananas and plantains do not
  contain seeds. Why do you think this is so?

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Our bananas are clonal

• http//www.askabiologist.org.uk/answers/viewtopic.
  php?id123
• Sometimes you can see very tiny dot-like seeds
  near the centre of the banana, but they are
  infertile.  The reason for this, is that edible
  (the non cooking variety) are clonal, and to the
  best of my knowledge, all the bananas eaten in
  the 'West' are the 'Cavedish variety'.  Being
  clonal the genetics of one banana plant and
  another is the same, and this means that they are
  susceptible to diseases, and in the past
  cultivated bananas have been destroyed by
  bilght.  This has the potential to happen again. 
  If it does the banana producing industry will do
  what it did before we all ate the cavendish
  variety, it will cultivate a new one.

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Monocots

• Most monocots are non-woody or herbaceous their
  stems are soft and fleshy.
• Ornamental orchids, lilies, tulips, and other
  spring bulbs.
• food for land animals the most important
  monocots are the grasses.
• Cows and rabbits eat grasses, and obtain energy
  from the leaves of grass.
• Have bacteria in their digestive systems that
  produce enzymes able to cut the crossties in
  cellulose molecules, and thereby release glucose
  units. (mutualism.)
• Humans do not have bacteria that can digest grass
  blades (leaves), even if the leaves are boiled or
  chopped.
• We do, however, eat the seeds of grasses.

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Mmmm.

• Humans can digest most of the matter in the seeds
  of grass plants such as wheat, corn, and rice
  WE KNOW WHAT HAPPENS WHEN YOU DONT CHEW YOU
  CORN!
• Each of these seeds has large stores of
  carbohydrates, along with smaller amounts of
  protein and oils.
• Wild grasses produce seeds much smaller than
  those of todays prairie wheat.
• Varieties have been developed that produce more
  usable human food per plant.
• hybridization techniques have produced new
  varieties of wheat, oats, and barley that are
  both more climate-tolerant and disease-resistant
  than earlier varieties.

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Dicots (Mmm continued)

• Most of Canadas native tree species are dicots.
• Some of these deciduous trees are important
  economic resources in Canada
• Most native wildflower species are also dicots
  and a typical salad contains a diversity of
  dicots such as lettuce, tomatoes, radishes, and
  sunflower sprouts.
• Only the onions are monocots.
• The staple foods of many cultures, past and
  present, are dicots yams, potatoes, rutabaga,
  and cabbage are all rich in starch.
• Bean seeds are rich in protein, while bean pods
  are rich in vitamins.