The Diversity of Plants

Unit 7

Chapter 22

Nonvascular plant habitat

Near water source

Nonvascular plant size

Because nonvascular plants do not have xylem and phloem, they depend on diffusion to get water and nutrients to each cell.

Consequently, nonvascular plants cannot be large because cells farther away from a water source would die..

Rhizoids

Structures that are similar to roots that anchors and absorbs nutrients for the nonvascular plant

Alternation of generation life cycle

Antheridium: male structure that produces sperm

Archegonium: female structure that produces egg

Sperm + egg zygote

Alternation of generation life cycle

The zygote grows into a plant structure called a sporophyte.

The sporophyte produces spores by meiosis.

The spores grow into a plant structure called a gametophyte.

Alternation of generation life cycle

The gametophytes are either male or female. Male: antheridium Female: archegonium

Prothallus

The fern gametophyte body that develops male (antheridia) or female (archegonia) reproductive structures

Sorus on fronds

Structures underneath the frond leaflets of fern plants are called sorus.

These structures produce spores that germinate to form the prothallus.

Cones

The structures that bear the male and female reproductive parts in gymnosperms (exposed seed, vascular plants) that produce sperm and egg are called cones.

Most associate cones with pine trees.

Large cycad cone

Pollen grains

The male gametophytes of seeded plants are pollen grain, which are sperm and nutrients packaged within a protective coat.

These structures carry sperm cells to an egg.

Pine pollen grain with air pockets to help the structure stay afloat in the air

Pollen grains in flowering plants

Flowering plants produce pollen grains within the male reproductive structures on flowers.

Ovule in flowering plants

The ovule is a protected structure that produces eggs.

Seed development in flowering plants

Sperm + egg zygote The zygote develops into an embryo found

within a seed. The seed may have one or two structures

(cotyledons) that store food. Monocot: plants that make one cotyledon

seeds Dicot: plants that make two cotyledon seeds

Dicot seed germination (ex: bean)

Fruit

Only plants that produce flowers produce fruits.

The fruit is a covering that either helps the seed fly through the air or entices animals to eat the fruit to disperse the seeds.

Evergreen vs. deciduous plants

Evergreen: plants that retain leaves over winter

Deciduous: plants that drop leaves over winter

evergreen

deciduous

Annual plants

produce seeds that survive harsh winters, but parent plant dies after one year

Biennial plants

Life cycle lasts two generations (years) Year 1: develop root system, storing sugars Year 2: flowers, fruits, and form seeds

Perennial plants

Plants that live for multiple years, continuously producing viable seeds

Usually during winter, leaves drop but the wood stems survive.