Botany Final ANGIOSPERMS

Unique Characteristics

Flowers

What does the division Magnoliophyta entail?

• All angiosperms

• Magnoliopsida, Liliopsida

Describe the class Magnoliopsida

• Eudicots

• Vascular cambium and ringed bundles

• 2 cotyledons with 4-5 flower parts

• Pollen grain w/ 3 apertures

• Taproot system

Describe the class Liliopsida

• Monocots

• No vascular cambium, scattered bundles

• 1 cotyledon with 3 flower parts

• Pollen grain w/ 1 aperture

• Fibrous root system

What is the dominant generation?

Sporophyte

How has the gametophyte generation been reduced?

Both the archegonia and antheridia are gone, replaced by the embryo sac and pollen grains respectively

What are the evolutionary trends for flowers?

• Number of parts shifting from definite to infinite

• Shortening of floral axis

• Increased fusion of parts

• Ovary position moved from superior to inferior

• Perianth differentiating into calyx and corolla

• Actinomorphic symmetry → zygomorphic symmetry

Superior ovary

Ovary is situated above floral parts (hypogynous flower)

Inferior ovary

Ovary is situated below floral parts (epigynous flower)

What has replaced the archegonia?

Embryo sac

What has replaced the antheridia?

Pollen grains

Characteristics of pollen grain

• part of flower, not of separate structures

• held in the anther

• smaller, 2-3 celled

• no air bladders

• more diverse methods of dispersal

Describe the embryo sac

Produces megagametophyte through the division of the megaspore nucellus

• forms a 7-celled gametophyte

What are the 7 cells in the gametophyte?

1 large central cell, 3 small antipodal cells, 2 synergids, 1 egg

What are the components of the ovule?

• Nucellus

• Integuments

• Embryo sac

• Chalaza

• Funiculus

What are the components of the seed?

• Embryo

• Seed coat

• Nutritive tissue

What is an example of indirect pollination?

cross-pollination

What is an example of direct pollination?

self-pollination

Describe Double Fertilization

one sperm fertilizes the egg and the other fertilizes the polar nuclei

• results in formation of the endosperm to develop into the embryo

What are the advantages of the ovary developing into a fruit?

Protects the seed, expands dispersal methods

Floral factors that influence pollination

• flower color

• odor

• shape

• arrangement/location

• reward - nectar or pollen

• plant habitat/form

Methods of seed dispersal

• wind

• animal

• water

• expulsion

• human activity

Importance

• primary food source

• used for medicine or decor

• vital to ecosystem health

Which structures are from the GAMETOPHYTE generation?

• Embryo sac

• Megagametophyte

• Sperm

• Egg

Which structures are part of the SPOROPHYTE generation?

• Ovule

• Funiculus

• Embryo

• Nucellus

• Integuments/seed coat