Angiosperms—Flowering Plants

Angiosperms—Flowering Plants

Flowers and Fruits

Flowers and FruitsAngiosperms develop unique reproductive organs known as flowers.

Flowers and Fruits

Flowers are an evolutionary advantage because they

attract animals

, which then

transport pollen

from flower to flower.

Flowers contain

ovaries

, which surround and protect the seeds.

After pollination, the ovary develops into a

fruit

.

A fruit is a wall of tissue that surrounds a seed. A fruit

protects the seed and aids in its dispersal

.

Flower Anatomy

Flower Organs

Sepals (calyx)

Petals (corolla)

Stamen- Anther (produces pollen) and filament

Pistil (carpel)-stigma, style and ovary

Complete flower- has all 4 structures (incomplete lacks one or more)

Perfect flower- must have both stamen and pistil

Diversity of Angiosperms

Angiosperms are categorized in many ways:

monocots and dicots

woody and herbaceous plants

annuals, biennials, and perennials

An angiosperm can belong to

more than one category

.

Diversity of Angiosperms

Monocots and dicots are named for the number of seed leaves, or cotyledons, in the plant embryo. Monocots have one seed leaf, and dicots have two.A cotyledon is the first leaf or the first pair of leaves produced by the embryo of a seed plant.

Diversity of Angiosperms

Diversity of Angiosperms

Woody and Herbaceous Plants:Plant stems that are smooth and nonwoody are characteristic of herbaceous plants. Woody plants include trees, shrubs, and vines.

Annuals, Biennials, and Perennials

There are three categories of plant life spans

Annual

Biennial

Perennial

Plant life span is determined by

genetic

and

environmental factors

.

Diversity of Angiosperms

Annuals are plants that complete a life cycle in one growing season.

Biennials complete their life cycle in two years. In the first year, they germinate and grow roots, short stems, and sometimes leaves. In the second year, they grow new stems and leaves, produce flowers and seeds, and die.

Perennials

Perennials live for more than two years.

Plant Responses

Plant hormones help coordinate growth, development, and responses to stimuli

Hormones

Are chemical signals that coordinate the different parts of an organism. Hormones are made in one place and transported somewhere else

Plant Hormones

Any growth response

That results in curvatures of whole plant organs toward or away from a stimulus is called a tropism

Is often caused by hormones

If plant grows toward stimulus- positive tropism (away from stimulus is negative)

Examples of tropisms-1- phototropism (growth toward light source; 2- gravitropism (positive: downward growth of root; negative- upward growth of stem away from gravity; 3- Thigmotropism- Mechanical- growth toward point of contact (like a vine around fence or tree)