BLY 121: General Survey of Higher Plants

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Questions and Answers

What is the term used for the group of plants that belong to the Division Spermatophyta?

Flowering plants

Higher plants (correct)

Lower plants

Seedless plants

What is the characteristic of higher plants that enables them to reproduce without water?

Presence of trees and shrubs

Presence of seeds

Alternation of generation

Pollen tubes (correct)

Which of the following is a characteristic of spermatophytes?

Lack of alternation of generation

Dependence on water for reproduction

Absence of trees and shrubs

Production of seeds (correct)

What is the process by which spermatophytes reproduce sexually?

Pollination Signup and view all the answers

Which group of plants is more successful than the Gymnosperms?

Angiosperms Signup and view all the answers

What is the Sub-division of Spermatophyta that Gymnosperms belong to?

Gymnosperma Signup and view all the answers

What is the life cycle of spermatophytes characterized by?

Alternation of generation Signup and view all the answers

Which of the following is NOT a characteristic of higher plants?

Dependence on water for reproduction Signup and view all the answers

What does the Greek word 'gymnos' mean in the context of Gymnosperm?

naked Signup and view all the answers

What is characteristic of seeds of the flowering plants?

Enclosed within pericarps Signup and view all the answers

Which of the following Gymnosperms are often used as ornamentals in tropical areas?

Cycas species Signup and view all the answers

What is a benefit of Cycads?

They form symbiotic associations with nitrogen-fixing bacteria Signup and view all the answers

What is a characteristic of Conifer leaves?

They are needle or scale-like Signup and view all the answers

What is an economic importance of Conifers?

They are used as a tree crop for pulp and timber Signup and view all the answers

Why are Conifers valued as landscape plants?

They are evergreen Signup and view all the answers

What is a characteristic of Conifer stems?

They become woody with age Signup and view all the answers

What type of plants are gymnosperms?

Spore-bearing plants Signup and view all the answers

What is the dominant phase of the life cycle of gymnosperms?

Sporophyte Signup and view all the answers

What are the two types of spores produced in gymnosperms?

Microspores and megaspores Signup and view all the answers

What develops from the microspore?

Pollen grain Signup and view all the answers

What is the role of the megagametophyte?

Produces egg cells Signup and view all the answers

How are pollen grains transferred between plants?

By wind or insects Signup and view all the answers

What is the result of fertilization in gymnosperms?

Formation of a zygote Signup and view all the answers

What is the function of the female gametophyte in a gymnosperm seed?

Serves as a food supply Signup and view all the answers

What is the approximate number of living species classified in angiosperms?

260,000 Signup and view all the answers

Where can angiosperms not be found?

Mountaintops Signup and view all the answers

What is the function of the endosperm in a seed?

It provides nutrients to the developing embryo Signup and view all the answers

What is the term for the structure that encloses the ovules in an angiosperm?

Carpel Signup and view all the answers

What is the process by which an angiosperm forms an endosperm?

Double fertilization Signup and view all the answers

What is the term for the type of plant that lives on another plant?

Epiphyte Signup and view all the answers

What is the purpose of the stigma in an angiosperm?

It is where pollen germination takes place Signup and view all the answers

What is the term for the type of tissue found in the phloem of an angiosperm?

Sieve tubes and companion cells Signup and view all the answers

What is the life cycle of an angiosperm that lives for one growing season or one year?

Annual Signup and view all the answers

What type of angiosperm has a life cycle of two years or growing seasons?

Biennial Signup and view all the answers

What is the term for an angiosperm that produces two seed leaves?

Dicotyledon Signup and view all the answers

What happens to the stems of herbaceous perennials during the winter?

They die Signup and view all the answers

What is the purpose of food storage organs in biennials?

To fuel future growth Signup and view all the answers

What happens to the plant after pollination and fertilization in an annual?

It dies Signup and view all the answers

What is a characteristic of woody perennials?

They have protective bark Signup and view all the answers

What is the term for an angiosperm that lives for three or more growing seasons?

Perennial Signup and view all the answers

Study Notes

Higher Plants: Spermatophyta

Higher plants are classified under the Division Spermatophyta, characterized by the production of seeds.
Spermatophytes are the most highly developed and evolved of all plants.

Characteristics of Higher Plants

Spermatophytes produce seeds, which are specialized structures for reproduction.
They exhibit alternation of generation, characterized by the alternation of two generations (gametophyte and sporophyte) within the life cycle.
Many members of Spermatophyta are trees and shrubs.
They are not dependent on water for sexual reproduction, possessing pollen tubes that transport male gametes to female gametes.
Spermatophytes are characterized by the phenomenon of pollination, a process in their sexual reproduction.

Gymnosperms

Gymnosperms are a major subdivision within the Division Spermatophyta, less highly developed than the Angiosperms.
They are characterized by producing seeds in the naked form, without being enclosed within pericarps.
Examples of gymnosperms include cycads and conifers.
Cycads are tropical palm-like trees that form symbiotic associations with nitrogen-fixing bacteria.
Conifers are often large and can dominate plant life in some ecosystems, with stems that continue to expand in width and length throughout their life.
Conifer leaves are needle or scale-like.

Life Cycle of Gymnosperms

Gymnosperms are spore-bearing plants (sporophytes) with a sporophyte-dominant life cycle.
Two spore types, microspores and megaspores, are produced in pollen cones or ovulate cones, respectively.
A short-lived multicellular haploid gamete-bearing phase (gametophyte) develops inside the spore wall.
Pollen grains (microgametophytes) mature from microspores and produce sperm cells.
Megagametophyte tissue develops in the megaspore of each ovule and produces multiple egg cells.
During pollination, pollen grains are physically transferred between plants, from pollen cone to ovule.
Two main modes of fertilization are found in gymnosperms: motile sperm that swim directly to the egg inside the ovule, and sperm with no flagella that are conveyed to the egg along a pollen tube.

Angiosperms

Angiosperms, or flowering plants, are one of the major groups of extant seed plants, with at least 260,000 living species classified in 453 families.
Angiosperms occupy every habitat on Earth except extreme environments such as the highest mountaintops, the regions immediately surrounding the poles, and the deepest oceans.
They are crucial for human existence, as the vast majority of the world's crops are angiosperms, as are most natural clothing fibers.

Characteristics of Angiosperms

Angiosperms are clearly united by shared, derived features, including:
- Ovules that are enclosed within a carpel (a structure made up of an ovary, which encloses the ovules, and the stigma, where pollen germination takes place).
- Double fertilization, which leads to the formation of an endosperm (a nutritive tissue within the seed that feeds the developing plant embryo).
- Stamens with two pairs of pollen sacs.
- Features of gametophyte structure and development.
- Phloem tissue composed of sieve tubes and companion cells.

Angiosperm Longevity

Angiosperms vary widely in longevity, with some living hundreds of years (trees, for instance) while others die after only one season.
Life cycles are measured in a circular fashion, from seed to seed.
Annuals live for one growing season or one year, biennials live for two years or growing seasons, and perennials live for three or more growing seasons.

Annuals, Biennials, and Perennials

Annuals sprout from a seed, creating vegetative growth, flowering, and producing seeds before dying.
Biennials sprout from a seed, creating vegetative growth, but instead of flowering, they create food storage organs like bulbs or tubers to fuel future growth.
Perennials may be woody or herbaceous, sprouting from seed, growing, and flowering, with the stems of herbaceous perennials dying over the winter and the roots surviving, while the woody perennials go into dormancy over the winter and renew their growth the following spring.

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Description

A lecture on the characteristics of higher plants, including their production of seeds and classification into two main groups.