Ch. 30 Seed Plants – Flashcards

reduced gametophyte heterospory pollen ovules seed

Bryophyte gametophytes are large and not dependent on sporophyte. They must fend for themselves. Seed plant gametophytes are small and develop inside of the sporophyte. They are dependent on the sporophyte

Megasporangium Megaspore which develops into the female gametophyte integument which grows into the seed coat once fertilized, ovules become seeds

They eliminate the need for water in fertilization

Seeds can survive harsh conditions through dormancy, are distributed far from their parent sporophyte, and are multicellular.

Spores like moss spores for example, can survive harsh conditions that the moss plants themselves cannot survive. Tiny size enables easy distribution. Seeds are not as easily distributed due to their large size. They are very complex and resistant which enables them to be dormant until prime germinating conditions are present.

The climate became warmer and dryer, favoring the spread of gymnosperms because of their ability to regulate water loss.

Coniferophyta Cycadophyta Gingkophyta Gnetophyta

Anthophyta

Yes all seed plants are heterosporous

The ovule becomes the seed

Spore are unicellular

Seeds are multicellular

Permits a dormant stage in life cycle Embryonic plant is well-developed prior to dispersal Food reserve Multicellular seed coat

Their large size makes them difficult to disperse

Spore (n) Microspore Megaspore Gametophyte (n) Microgametophyte produces sperm Megagametophyte produces egg Pollination and Fertilization Zygote (2n) Embryo (2n) Sporophyte (2n) produces spores (n)

Sporophyte structures

All gymnosperms are woody. None are herbaceous or flowering

Thick cuticle, sunken stomata and endodermis prevent water loss

No

Female megasporangia are on top of the megasporophyll

Male microsporangia lie below the microsporphyll

Conifers are monoecious

conifers

conifers

Reduced archegonium No antheridia 2 sperm non-flagellated sperm

cycadophyta is the oldest extant seed plant

Cycadophyta

Curled ends and palmlike

Dioecious

Largest sperm Flagellated sperm

cycads male cones generate heat

Cycads have fleshy fruit for animal dispersal

Gingkphyta trees at 1000+ years

Gingkos are dioecious

Flagellated sperm

Gingkos

nonflagellated sperm tracheids and vessel elements Some produce nectar

Gnetophyta with species Ephedra (2 embryos)

Gnetophytes

Gnetophyta

n most conifer species, each tree has both ovulate and pollen cones. The pine tree is the sporophyte. Each ovulate conecontains megasporangium. Microsporangium undergoes meiosis, producing haploid micropsores that develop into pollen grains. A pollen grain enters through the micropyle and germinates, forming a pollen tube that digests throughthe megasporangium. By meiosis, four haploid cells are produced. One survives as a megaspore. Female eggdevelops. Fertilization occurs as sperm and egg nuclei unite. The ovule becomes a seed

A fruit is a mature ovary of a flower that protects dormant seeds and aids in dispersal. Some are dispersed by wind or animals. Many fruits are edible so that they are broken down in animal digestive systems and deposited in feces. Fleshy or dry

Smells Ex:dung beetle Taste Timed development with coevolution

Grains are a dry fruit with a mature ovary inside

Lab manual

A generative cell divides to form two sperm A tube cell produces the pollen tube

Double fertilization is a mechanism in angiosperms in which two sperm cells unite with two cells in the embryo sac to form the zygote and endosperm. It might sync the development of food storage in the seed with the development of the embryo

Monocot Petals: 3 Dicot Petals: 4,5 Monocot cotyledon 1 Dicot cotyledon 2 Monocot veination: parallel Dicot veination: net

Plants have changed characters like petal color, seed and fruit to attract pollinating insects and dispersing animals Coevolution has increased plant and animal diversity

They do not have ovaries in common

Megaspores or microspores

A seed includes contriubitions from 3 separate generations of plants. In addition to a sporophyte embryo, a seed has a seed coat derived from the integuments of the "grandparent" sporophyte and a food supply derived from the tissues of the "parent" gametophyte.

a male gametophyte within a pollen grain