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Chapter 26: Seed Plant Evolution - Coggle Diagram
Chapter 26: Seed Plant Evolution
Reproductive Adaptations
Pollen
Mature Male Gametophytes (2-3 Cells) With Sporopollenin Protective Coating
Pollen Grains Travel (Air or Animal) to Reach Ovule-Bearing Parts (Pollination)
Microspores Retained & Mature Into Pollen Grains Within Microsporangium
Grows Pollen Tube Toward Egg Within Ovule
Sperm Released in Tube (No Flagella in Conifers & Angiosperms)
Fertilization Within Ovule (No Water Needed)
Seed
Develops from Fertilized Ovule
Embryo, Food Supply, Seed Coat
Advantages
Enhanced Dispersal
Safe From Desiccation
Underground Germination
Stored Food Allows Embryo Growth Without Photosynthesis
May Stay Dormant Until Conditions are Optimal
Ovules
Megasporangium with Retained Megaspore & Surrounding Sporophyte Tissue
Megaspore Grows Into Female Gametophyte
Egg Produced & Fertilized Within Ovule
Gametophytes
Heterosporous
Microspores
Grow Into Male Gametophytes
Megaspores
Grow Into Female Gametophytes
Both Mature Within Sporangia
Highly Reduced in Size
Protected from Desiccation & UV Light
Reduced & Retained
Gymnosperms
Cycads
Fern-Like or Palm-Like Fronds Radiate from Central Stem
Central Female & Male Cones
Flagellated Sperm
Gnetophytes
Three Distinct Genera
Male & Female Strobili
Sperm Not Motile
Ginkgos
One Extant Tree (Ginkgo Biloba)
Herbal Medicine
Flagellated Sperm
Conifers
Most Diverse Gymnosperms
Cone-Bearers
Male Pollen Cone
Sperm Not Motile
Female Ovulate Cone
Dominate High Altitude & Latitues in Northern Hemisphere
Evergreen With Needle-Like Leaves
Several Record-Breakers
Life Cycle
Ovules Born Exposed on Sporophylls
Usually Arranged in Strobili Cones
No Flower & No Fruit
Pollen Typically Carried by Wind
Angiosperms
Life Cycle
Pollen Grains Form in Anthers
Ovules Enclosed Within Ovary
Pollen Lands on Stigma
Pollen Tube Grows Through Style & Ovary
Double Fertilization
One Sperm Nuclei Fuses With Egg (Zygote)
Other Sperm Nuclei Fuses with Two Central Nuclei, Forming 3n Endosperm Food Supply in Seed
Fertilization Stimulates Ovary Wall & Other Parts to Develop Fruit
Phylogeny
Anthophyta
Extant Basal Relicts
Amborella
Water Lillies
Star Anise
Magnoliids
Magnolias
Nutmeg
Monocots
Ample Endosperm
One Seed Leaf (Cotyledon)
Veins Parallel
Vascular Tissue Scattered
Fibrous Root System
Floral Organs in Multiples of Three
Grasses, Grains, Palms, Lilies, Onions
Eudicots
Absorbed Endosperm
Two Seed Leaves (Cotyledons)
Veins Netlike
Vasular Tissue in Ring
Taproot (Main Root)
Floral Organs in Multiples of Four or Five
Most Vegetables, Fruits, Trees, Shrubs
Derived Characteristics
Flower
Protects Ovules Within Ovary
Promotes Efficient Pollen Transfer (Pollinators)
Four Whorls of Modified Sporophylls
Stamen
Anther
Filament
Carpel (Pistil)
Style
Ovary
Stigma
Anatomy Relates to Pollenation
Can be Incomplete
Unisex Flowers (Only Carpels or Stamens) Promote Outcrossing
Monoecious (Both Sexes on Same Plant)
Dioecious (Each Sex on Separate Plant)
No Petals if Wind-Pollinated
Can Form Inflorescence
More Attractive to Visual Pollinators
Spadix (Thousands of Flowers Enclosed by Modified Leaf)
Coevolution
Plants
Selection for Displays & Scents That Attract Visitors
Selection for Best Pollinator Loyalty with Cheapest Reward (Pollen Before Nectar)
Pollinators
Selection for Senses / Anatomy That Help Locate Flower & Get Reward
Some Depend Totally on Flowering Plants (Butterflies & Moths)
Sometimes Tricked (Pollinate But Gain No Reward)
Fruit
Enhances Seed Dispersal
Protects Dormant Seed
Derived from Ovary Tissue After Fertilization
Fleshy Fruit
Developed from Ovary Wall
Adapted to be Eaten by Animals
Scattered or Pass Through Gut Into Feces
Pit Contains Seed From Ovule
Dry Fruit
Disperse by Wind, Water & Animals
Some Throw Seeds
Some Protect Dormant Seeds
Seed Plants & People
Almost All Food, Beverages & Spices (80% Global Calories)
Wood Products (Paper)
Fuel
Fiber
Clothing & Rope
Cotton, Linen, Jute, Hemp
Secondary Compounds
Drugs & Medicines
Perfumes
Latex Rubber
Outdoor Recreation
Carnivorous Plants
Pitcher Plants
Venus Flytraps
Sundews
Parasitic Plants
Dodder
Indian Pipe
Mistletoe