Botany

• This subject is designed to enhance the understanding of the principles and concepts in the study of biology, particularly heredity and variation, and the diversity of living organisms, their structure, function, and evolution
• The diversity in structure and function of organisms enables them to adapt and survive in the type of environment they inhabit
• The development of adaptive mechanisms for their survival and continuity leads them to become more and more complex
• This chapter will provide emphasis on the various processes in plants and animals responsible for the maintenance and continuity of life
• Botany


  The scientific study of plants, including their structure, how they grow, how they can be effectively classified, and the things that impact their development
• Aristotle


  • Founder of Plant Science
  • Wrote that all plant life is lower and less specialized than animal life
• Theophrastus


  • Father of Plant Science
  • Wrote "History of Plants" and "Causes of Plants"
  • Most outstanding botanist in the early botany
• Plants


  • Multicellular living things that come in different shapes and sizes
  • Some are short-lived, others live for hundreds of years
  • Usually in green color
  • Have adapted to a wide variety of habitats, and methods of reproducing and dispersing themselves
• Plants


  • Columbine (short-lived, 3-4 years)
  • Sequoia (oldest known specimen 3,266 years old)
  • Great Basin Bristlecone Pine (over 5,000 years old)
  • Pando (oldest living tree colony, over 80,000 years old)
• Plants


  • Autotrophs
  • Utilize light energy and convert it to chemical energy
  • Anchored in the soil but capable of movement called tropism
• Plant organs


  • Leaves
  • Stem
  • Roots
  • Flowers
  • Fruits
  • Seeds
• Phototropism


  Movement of plants in response to light
• Plant forms


  • Trees
  • Vines
  • Weeds
  • Grass
  • Conifers
  • Cacti
  • Herbs
  • Green algae
• Spermatophytes


  Seed plants
• Seed plant groups


  • Gymnospermae (seed plants without flowers)
  • Angiospermae (seed plants with flowers)
• Gymnospermae


  • Seeds not enclosed in a fruit, often borne on a scale-like structure called cones
  • Examples: Pine, spruce, fir
• Angiospermae


  • Produce flowers as well as seeds
  • Seeds contained in an enclosed structure called fruits
• Flowering plant groups


  • Dicotyledon/dicots
  • Monocotyledon/monocots

  
• Dicotyledon/dicots


  • Form the largest group with a great variety of trees, shrubs, vines, and herbaceous plants
  • Have broad leaves with netted venation
  • Flower parts frequently in whorls of four or five and 2 cotyledon as part of the embryo in the seed

  
• Monocotyledon/monocots


  • Have generally long narrow/linear leaves with the vein parallel to the central vein (midrib)
  • Have only one cotyledon in the seeds
  • Sepal and petal generally occur in threes or multiple of three
• Seedless vascular plants


  • Plants that contain vascular tissue, but do not produce flowers or seeds
  • Reproduce using haploid, unicellular spores instead of seeds
  • Example: ferns
• Nonvascular plants

  • Also called bryophytes
  • Lack roots, stems, and leaves
  • Low-growing, reproduce with spores, and need a moist habitat
  • Example: moss
• Unifying themes of plants

  • Plants are highly integrated organisms consists of an organized parts
  • Plants exchange energy with their environment
  • Plant metabolism is based on the principles of chemistry
  • Plants respond and adapt to their environment
  • Plants reproduce by passing their genes and information to their descendants
  • Plants share parts of common ancestry
• Leaves are the lateral outgrowth of the stem, typically thin, flat, expanded green structure of a plant, highly effective energy converters

  
• Parts of a leaf

  • Blade
  • Petiole
  • Stipule
  • Midrib
  • Veins

  
• Blade


  Broad, flat, expanded light harvesting portion of the leaf
• Midrib


  Long thickened structure which is a continuation of the petiole up to the opposite end of the leaf

  
• Veins


  Networks found in both sides of the midrib which is the continuation of the vascular tissue
• Petiole


  Stalk which is cylindrical and attaches the blade to the stem
• Stipules


  Earlike lobe at the base of the petiole
• Variation of leaves


  • According to composition (simple and compound)
  • According to venation (parallel and netted)
  • According to texture (fleshy, succulent, coriaceous, chartaceous, membranous)
  • According to shape

  
• Stem


  • The plant axis that bears buds and shoots with leaves and, at its basal end, roots
  • Conducts water, minerals, and food to other parts of the plant
  • May also store food, and green stems themselves produce food
  • Composed of vascular tissues
• Modified stems


  • Bulb
  • Clove
  • Tuber
  • Rhizome
  • Runner/Stolons
• Roots


  • The organ of a plant that typically lies below the surface of the soil
  • Four major functions: absorption of water and inorganic nutrients, anchoring of the plant body to the ground and supporting it, storage of food and nutrients, vegetative reproduction and competition with other plants
• Types of roots


  • Tap root
  • Fibrous root
  • Adventitious root
• Stem structures


  • Strings
  • Clusters underneath parent plants
  • STEM
  • Modified Stems
• Rhizome


  Large creeping rootstock or underground stems (e.g. ginger)
• Runner / Stolons


  Horizontal, aboveground stems (e.g. Strawberries)
• Root's four major functions

  • Absorption of water and inorganic nutrients
  • Anchoring of the plant body to the ground, and supporting it
  • Storage of food and nutrients
  • Vegetative reproduction (asexual reprod.) and competition with other plants
• Tap root


  Large, central, and dominant root from which other roots sprout laterally. Typically a tap root is somewhat straight and very thick, is tapering in shape, and grows directly downward.