Sexual Reproduction

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Sexual Reproduction

• requires the fusion of two different sets of DNA.
  It increases the amount of variety in organisms

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Conjugation

• the sexual process where genetic material is
  transferred from one cell to another by a
  cell-to-cell contact
• IN ALGAE -tube that allows the transfer of DNA

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Conjugation

• IN BACTERIA - Some bacteria transfer genetic
  material. Some bacterial also have plus and minus
  strains.
• These are attracted to one another.
• A bridge is formed between them. Genetic
  material in the form of a plasmid moves from the
  plus to the minus.

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Alternation of Generations

• Plant Reproductive cycles - have phases called
  generations
• In mosses
• sporophyte generation
• gametophyte generation (majority of life spent
  in this phase)

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Alternation of Generation
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Sporophyte generation

• Diploid
• That creates spores that are 1N and grow into
  gametophyte

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Gametophyte

• Gametophyte (1N) produces gametes which fuse in
  zygote to form sporophyte generation

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Flowering plants

• Sporophyte generation (majority of time spent in
  this phase)
• Gametophyte limited to stamens and pistils

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Flowers

• Mainly to attract pollinators
• Female part carpel
• Male part stamen

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Flowers are unique to pollinators

• Self pollinating plants
• Reduced flowers
• Pale colors or green
• Some dont open

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Wind pollinated

• Flowers often absent
• Anthers dangle lower than stigma
• Pollen is light
• Stigmas are large and often feathery

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Insect pollinated flowers

• showy, pungent, nectar producing flowers.
• multiple blooms per plant and these flowers open
  at different times.
• purple, yellow,blue, and red, although they can
  be any color.
• have landing pads
• their anthers are positioned to dust insect.
• The stigmas are positioned to collect the pollen.

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Bird pollinated flowers

• Tend to have larger nectaries
• Tend to be red
• Dangle

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Bat pollinated flowers

• Bats fly at night so they dont have a lot of
  light to see with and have poor vision, therefore
  there is no need for the plant to waste energy
  producing color white
• At the same time they need to be BIG and form a
  funnel that reflects sound waves well.
• They need to have a big NECTAR payoff also.

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Pollination

• pollen forms a pollen tube that burrows through
  the style toward the ovule.
• two sperm nuclei slide down the tube.
• One sperm fuses with the nuclei in the center of
  the ovule and will form the endosperm (food
  supply for the seed)
• the other fuses with the egg to form a
  zygote/embryo.

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Seeds

• Embryo endosperm seed

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Monocots vs Dicots

• Monocots
• Single cotyledon
• Parallel venation
• Flower parts in 3s
• Random vascular bundles in stem
• Dicots
• 2 cotyledons
• Branched venation
• Flower parts of 4s 5s
• Radially arranged vascular bundles in stem

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Monocot seed parts

• Endosperms -food source
• Radicle - becomes root
• Hypocotyl- becomes stem below leaves
• Epicotyl - becomes stem above leaves

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Dicot seed parts

• Same parts

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What seed parts become

• Hypocotyl
• Epicotyl

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Seed dispersal

• Wind
• Seed characteristics light, feathers, wings,
  airfoil, huge numbers produced (maple)
• Water
• the Seed needs to be water proof, lighter than
  water (coconut)

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Animals

• Eating fruits - Enlarged ovaries
• Poop out small seeds
• Sticking to fur

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Fruits

• Flower petals falls off and ovary enlarges around
  the fertilized ovums zygotes
• Zygotes undergo mitosis to become embryo part of
  seed.
• Rest of ovary enlarges to become fruit.