Angiosperms Notes

Angiosperms dominance on terrestrial ecosystems
Main parts of a flower and their functions
Typical lifecycle of an Angiosperm
Comparative analysis of similarities and differences in the two main groups of flowering plants

Flower Structure (Figure 26.14)
Modified Leaves (sporophylls): Surround central receptacle
Perianth: Combinations of sepals and petals
- Sepals: Base of flower attachment; encloses unopened floral bud
- Petals: Located inside the whorl of sepals; attract pollinators
Gynoecium: Female part of the flower
- Composed of one or more Carpels
- Pistil: Multiple carpels
- Stigma: Pollen receptacle
- Style: Connecting structure where the pollen tube grows
- Ovary: Houses ovules
Androecium: Male part of the flower
- Stamen: Comprises stalk (filament) and anther (pollen sac)

Life Cycle of an Angiosperm (Figure 26.15)
Double Fertilization:
- Produces Zygote (first fertilization) and Endosperm (second fertilization)
Embryo contains:
- Radicle: Small root
- Cotyledons: Leaf-like organs
Fruits:
Formed when ovary walls thicken post-fertilization
Types of fruits:
- Fleshy: Examples include berries, apples, grapes
- Dry: Examples include nuts, rice, wheat
Not all fruits develop from a single ovary
Aid in seed dispersal

Phylum: Anthophyta encompasses all Angiosperms
Basal Angiosperms: Includes groups like Magnoliidea (magnolias, laurels, peppers)
Examples of laurels include avocado, cinnamon, spicebush
Monocots:
Characterized by a single cotyledon
Vascular tissue is scattered in stems; forms a ring in roots
No taproot present
Examples include lilies, orchids, grasses
Dicots:
Characterized by two cotyledons; flowers typically arranged in multiples of 4 or 5
May be herbaceous or woody
Has a main taproot
Represent approximately 2/3 of all flowering plants