Introduction to Angiosperms

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Introduction to Angiosperms!
"Flowering Plants"
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Overview
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Quick Review!Gymnosperms

• Naked seed
• Cones as reproductive structures
• Thin, needle like leaves
• Large growing plants

Video http//www.youtube.com/watch?vph7Ex8rQ-IA
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Another class of seed plants Angiosperms

• Overview of lesson
• Adaptive features
• Flowers
• Fruits
• Unique reproductive cycle

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(No Transcript)
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Flowers

• Modified leaves
• Reproductive structures
• Allow for greater reproductive success
• More attractive

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Structures of a flower

• Petals
• Sepal
• Stamen
• Anther
• filaments
• Pistil
• Stigma
• Style
• ovary

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Petals/Sepal

• Petals
• Highly modified leaves
• Brightly colored
• Function attract pollinators
• Sepals
• Enclose the flower before it opens

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Stamen

• Male part of the flowers
• contain
• Anther where pollen grains are formed
• Filament stalk that hold anther

http//faculty.clintoncc.suny.edu/faculty/Michael.
Gregory/files/Bio20102/Bio2010220lectures/Seed
20Plants/seed20plants.htm
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Pistil (carpal)

• Stigma
• Sticky part where pollen lands
• Style
• Slender stalk where pollen grain reaches the
  ovary
• Ovary
• Where the ovule (egg) is contained

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Fruits!

• Once fertilized, ovary becomes fruit- bears seeds
• Function protection and dispersal of seeds
• Can be either fleshy ex peaches tomato oranges
  or
• dry ex nuts and raisins

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Types of fruits

• Simple flower with only 1 pistil
• Apples, tomatoes
• Multiple fruit formed from a cluster of flowers
• Fruits fuse into one big mass
• pineapples

• Aggregate flower with numerous pistils
• Ex raspberries

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Reproduction!
biology.clc.uc.edu/courses/bio106/angio.htm
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Alteration of generation review!

• a haploid gametophytic stage alternates (through
  time and generations) with a sporophytic stage
• haploid 1N number of chromosomes, diploid 2N

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Overview of life cycle

• In ovule- production of megaspores (n) via
  meiosis
• Megaspores ---mitosis---megagametophyte
• In anther-production of microspores (n) via
  meiosis
• Microspores----mitosis----microgametophyte
  (pollen grain)

http//faculty.clintoncc.suny.edu/faculty/Michael.
Gregory/files/Bio20102/Bio2010220lectures/Seed
20Plants/seed20plants.htm
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Overview of life cycle

• Megagametophyte contains egg (n)
• Microgametophyte (pollen) produces sperm (n)
• Pollen (containing sperm) reaches the ovule
• Egg and sperm meet Fertilization

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Overview of life cycle

• After fertilization
• zygotes
• embryo (2n)
• Fruit develops
• from ovary
• Seed develops
• from ovule
• Seed germinates to
• form Sporophyte
• (mature plant) (2n)

http//www.ualr.edu/botany/botimages.html
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Double fertilizationunique to flowering plants

• Once pollen tube enters ovary
• 1 sperm fertilizes ovule to form zygote (seed)
• Another sperm combines with rest of ovule to form
  endosperm
• Provides nourishment to developing embryo

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• The growing zygote ( embryo) feeds on the
  endospore until it grows leaves and can make its
  own food.

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Quiz!
http//www.cartage.org.lb/en/themes/Sciences/Botan
icalSciences/PlantReproduction/Angiosperms/Angiosp
erms.htm
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How does the pollen get to the pistil????

• Pollination transfer on
• pollen to plant pistil
• Pollen dispersal agents
• Wind- these pollen
• grains are light weight,dry and
• easily blown by wind
• Animals- ex insects. Attracted to brightly
  colored and sweet smelling flower. This Pollen
  is sticky and adheres to animals body.

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Seed Dispersal

• Seeds are dispersed away from parent for
  decreased competition and increased survival but
  how???
• Wind- some seeds are lightweight therefore can be
  carried ex dandelions
• Water- air trapped in seeds
• that allows them to float
• ex water lilies
• Animals-
• feed on fruit/berries
• Stick to body-sticky,
• spiny seeds