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Seed Plants Chapter 30.

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Presentation on theme: "Seed Plants Chapter 30."— Presentation transcript:

1 Seed Plants Chapter 30

2 Seed Plants Gymnosperms vs Angiosperms Gymnosperms
3 Major evolutionary changes in gymnosperms Further decrease in prominence of the gametophyte generation Pollination Evolution of the seed


4 5 Crucial Seed Plant Adaptations
1. Reduced gametophyte Now gametophyte is dependent on sporophyte Unlike in ________, where ________________ 2. Heterospores Megaspores = produce female gametophyte  eggs Microspores = produce male gametophyte  sperm 3. Ovules and production of eggs Protection of egg and developing zygote Increases reproductive fitness (likelihood of successful production of offspring)

5 4 & 5 Crucial Adaptations 4. Pollen & sperm production 5. Seeds
Pollen grain contains sperm nuclei Pollen grain has waterproof coating No more water needed for sperm to travel to the egg Now it is the wind that disperses sperm 5. Seeds Seeds > spores Multicellular Layers of protective tissue Stored energy for the development of the embryo


7 Ovule to Seed Megaspore = Female spore (heterosporous)
-- Megaspore  female gametophyte -- Female gametophyte produces egg (n) -- Female gametophyte becomes nutrition for developing embryo

8 Gymnosperms “naked” seeds Conifers (Coniferophyta)
Not enclosed in ovaries (fruits) Seeds are typically in cones that allow for airborne dispersal Conifers (Coniferophyta) Pines, spruces, firs, and redwoods

9 Conifers have Ovulate & Pollen cones
Megasporangium undergoes meiosis = 4 haploid cells, but only 1 becomes megaspore Multiple archegonia are produced inside each gametophyte = multiple eggs produced Only 1 fertilized egg develops into the embryo, others dissolve

10 Gymnosperm Life Cycle Notes
Megasporangium (2n) – produces 4 megaspores (n) Via meiosis 3 spores (n) dissolve leaving 1 megaspore Megaspore (n) – develops into the female gametophyte (n) Female gametophyte contains multiple archegonia Multiple egg production Sperm nuclei from pollen fertilizes egg(s) Only one fertilized egg is able to survive

11 Questions? What is the correct term for the pine tree? Diploid or haploid? What is the correct term for the cones on the pine tree? Diploid or haploid? Yellow cones are_______, pine cones are _______ How is the pollen dispersed? What does the pollen produce?

12 What becomes of … ? Megasporangium? Megaspore? Egg, if fertilized?
Ovule? Female gametophyte?

13 Angiosperms Fruits, Flowers, and double Fertilization
90% of all plant species Seeded + Vascular Flower – structure for sexual reproduction Fruits – mature plant ovaries (yes, you are eating plant ovaries) Double fertilization 1 sperm fertilizes egg = zygote 1 sperm combines with 2 nuclei in ovule = endosperm

14 Angiosperms – 2 classes Monocots Dicots (Eudicots)
Monocots have 1 cotyledon (structure that nourishes the developing plant) Parallel veination in leaves Orchids, lillies, and grasses Dicots (Eudicots) 2 cotyledons in the seed Netted veination in leaves Roses, peas, beans, oaks

15 Stamen = Male -- Anther + filament -- Microspores produced in anther Carpel = female -- Ovary -- Stigma, style -- Megaspores produced in Ovules inside Ovary Petals – attract pollinators

16 Fruits -- Can be wet or dry
-- Wet fruits – oranges, plums, grapefruit, tomatoes -- Dry fruits – Beans, nuts, & grains


18 Life Cycle Notes Male gametophytes and are inside pollen grains
Microspore  pollen grain (n) No real antheridia to speak of Megasporangia produce megaspores (n)  female gametophyte  eggs ‘n stuff Double fertilization After male gametophyte produces pollen tube 1 nuclei fertilizes egg cell = zygote 1 nuclei fertilizes 2 nuclei in ovule = 3n endosperm

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