Biology Chapters 30 and 31

Vascular plants are grouped into 3 clades, name them.

(1) lycophytes (club mosses), (2) pterophytes (ferns and their relatives), and (3) seed plants

Explain the haplodiplontic life cycle in angiosperms. What is the male gametophyte? What is the female gametophyte? Explain what happens during double fertilization. What is the outcome?

1. pollination 2. mitosis of generative cell 3. pollen tube growth 4. pollen tube enters embryo sac 5. union of sperm and egg 6. union of sperm and egg polar nuclei 7. formation of zygote and endosperm

microspore

A developing pollen grain at the uninucleate stage in seed plants. The spore produced by sporophytes. It is haploid and gives rise to a male gametophyte.

Ovule

A female gametophyte forms within the protection of the integuments. In angiosperms, they are completely enclosed within additional diploid sporophyte tissue

Pollen grains (generative cell, sperm, pollen tube)

A multicellular male gametophyte carrying the male gamete, a sperm cell. Generative cell- During growth of the pollen tube, one of the pollen grain's four cells, the generative cell, divides by mitosis, with one of the resulting two cells dividing once more. These last two cells function as sperm pollen tube- a hollow tube that develops from a pollen grain when deposited on the stigma of a flower. It penetrates the style and conveys the male gametes to the ovule.

Distinguish between pollen and sperm in seed plants.

A pollen grain is not motile. It needs a pollinator to get to the female part of the plant, whether a bee, a bird, or the wind or water. A sperm cell has it's own energy source (mitochondria) and has a tail so it can move itself towards the egg.

Seeds

A vehicle for dispersing the embryo to distant sites

Describe the distinguishing characteristics of angiosperm.

All angiosperms have flowers at some stage in their life Angiosperms have small pollen grains that spread genetic information from flower to flower All angiosperms have stamens Angiosperms have much smaller female reproductive parts than non-flowering plants, allowing them to produce seeds more quickly. Angiosperms have carpels Production of endosperm

Explain why chlorophytes are considered close relatives of land plants.

Chlorophytes are considered close relatives of land plants because they are a type of green algea but they never made it to land

Explain why charophytes are considered the closest relatives of land plants (Chapter 29.5, p. 579)

Currently, the molecular evidence from rRNA and DNA sequences favors the charophytes as the green algal clade most closely related to land plants. Charophytes also have haplontic life cycles which is also found in land plants

Pterophytes consist of what types of plants? List features exhibited by pterophytes.

Ferns: Horsetail and Whisk

Understand the generalized multicellular plant life cycle -what is haplodiplontic?

Gametes are not the direct result of a meiotic division. Diploid sporophyte cells undergo meiosis to produce haploid spores. Each spore goes through mitotic divisions to yield a multicellular, haploid gametophyte.

Diplontic vs haplodiplontic life cycles

In gametic meiosis, instead of immediately dividing meiotically to produce haploid cells, the zygote divides mitotically to produce a multicellular diploid individual or a group of more unicellular diploid cells. Cells from the diploid individuals then undergo meiosis to produce haploid cells or gametes. Haploid cells may divide again (by mitosis) to form more haploid cells, as in many yeasts, but the haploid phase is not the predominant life cycle phase. In most diplonts, mitosis occurs only in the diploid phase, i.e. gametes usually form quickly and fuse to produce diploid zygotes. In sporic meiosis (also commonly known as intermediary meiosis), the zygote divides mitotically to produce a multicellular diploid sporophyte. The sporophyte creates spores via meiosis which also then divide mitotically producing haploid individuals called gametophytes. The gametophytes produce gametes via mitosis.

Micropyle

In the ovules of seed plants, an opening in the integuments through which the pollen tube usually enter

What is the evolutionary significance of tracheids?

It enables efficient delivery of water and nutrients throughout the organism

How did leaves evolve?

Leaves increase surface area of the sporophyte, enhancing photosynthetic capacity. Lycophytes have single vascular strands supporting relatively small leaves called lycophylls. True leaves, called euphylls, are found only in ferns and seed plants, having distinct origins from lycophylls. Lycophylls may have resulted from vascular tissue penetrating small, leafy protuberances on stems. Euphylls most likely arose from branching stems that became webbed with leaf tissue.

What 3 groups make up the bryophytes? Name characteristics of each.

Liverworts- form Gametangia in umbrella like structures Mosses- no vascular tissuse, gametangia form on tips Hornworts- sporophyte is photosynthetic & embedded in gametophyte tissue

Sporophyte (2n)

Multicellular diploid stage. Spore producing phase in the life cycle of a plant having alternation of generations

Gametophyte (n)

Multicellular haploid stage

Stamen (anther, filament)

Organ of the flower that produces the pollen. Each stamen consists of a pollen-bearing anther and a stalk called a filament, which may be missing in some flowers. The filament supports the anther, which is where pollen develops

Discuss the origin of land plants and the major innovations that have occurred. Fig 30.9

Origin of land plants essential to development of 1. good soils, 2. evolution of modern plants and 3. animal colonizing land. Seeds are highly resistant structures well suited to protecting the plant embryo from environmental stresses and to some extent from predators. In addition, almost all seeds contain a supply of food for the young plants. Fruits in the flowering plants (angiosperms) add a layer of protection to seeds and have adaptations that assist in seed dispersal, expanding the potential range of the species. Flowers allow plants to secure the benefits of wide outcrossing in promoting genetic diversity

Describe differences in sporophytes of the pterophytes.

Pterophytes require water for fertilization and are seedless.

Angiosperms

The flowering plants. The ovules at the time of pollination are completely enclosed by tissue

Double fertilization

The fusion of the egg and sperm (resulting in a 2n fertilized egg, the zygote) and the simultaneous fusion of the second male gamete with the polar nuclei (resulting in a primary endosperm nucleus, which is often triploid, 3n) a unique characteristic of all angiosperms

scales

The individual plates of a cone

Ovary

The ovule and the surrounding protective tissue

Pollination

The transfer of pollen from an anther to a stigma

Gnetophytes

They are the only gymnosperms with vessels in their xylem

What role do some animals play in the angiosperm life cycle?

They carry the pollen to the carpel

Describe the distinguishing characteristics of a gymnosperm.

They do not have an outer covering or shell around their seeds They do not produce flowers They do not produce fruits They are pollinated by the wind

Gymnosperms

a seed plant with seeds not enclosed in an ovary (ex. conifers)

What innovations contributed to the success of land plants that supported terrestrial animal life? a.Describe 4 ways in which seeds help to ensure the survival of a plant's offspring b.How does fruit develop? c.Distinguish between different types of fruit. d.How are fruits adapted for dispersal?

a. dormancy, protection, nourishment, dispersal b. The carpel (ovary) wall is composed of three layers: the exocarp, mesocarp, and endocarp. One, some, or all of these layers develops to contribute to the recognized fruit in different species. The seed matures within this developing fruit. c. Three layers of ovary wall, also called the pericarp, can have distinct fates, which account for the diversity of fruit types from fleshy and soft to dry and hard d. expulsion, wind, and by attaching to the fur or feathers of animals

Mycorrhizal associations

beneficial symbiotic relationship between fungi and plants

Bryophytes are also called nonvascular. Is this accurate? Why or why not? Can you name a better term?

bryophytes may have some tissue for water conduction, these plants stay small as the water cannot be lifted high above the ground because no lignin is present in this tissue. A better name would be non tracheophytes.

Sori

clustered sporangia on underside of fronds

Name the 4 groups of extant gymnosperms.

coniferophytes, cycadophytes, gnetophytes, and ginkgophytes

Fronds

fern leaves

Rhizomes

horizontal underground stem with vascular tissue that is used to anchor plant

Describe adaptations of bryophytes for life on the land.

motile to sessile (stationary) stomata, a waxy cuticle, and Rhizoids

Archegonia

plant structure that produces female gametes

gametangia

plant structure that produces gametes

Antheridia

plant structure that produces male gametes

Stomata

small openings in plants that can open and close to allow for gas and water exchange

What are the principal parts of a vascular plant?

stomata openings in leaves, roots, and shoots

Megaspore

the nucleus of the remaining megaspore divides mitotically, and the cell slowly expands until it becomes many times its original size

Phloem

vascular tissue that carries food

Xylem

vascular tissue that carries water