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Chapter 24

Page history last edited by Shelly Turner 14 years, 2 months ago

Chapter 24:  Introduction to Plants

 

Using your vocabulary words, make notecards/flashcards that you can use outside of class to study. 

 

Work on your Directed Reading in class every chance you get.  Remember that I will assist you on the harder questions.  This assignment is due the day we take the test on this chapter.  Use the information in this assignment as a study guide for your test.

This study guide is to help you study for your test.  It should not be the only item you use to study w hen preparing for the test.  Remember to complete your Directed Reading for every chapter along with writing your vocabulary words on notecards to help you remember them.  And always remember to listen carefully in lecture because all of the information in this study guide will be covered.

 

Chapter 24 Word Search

The World of Plants 


 

Video Questions

 

 

 

A. Current System of Classification

1.   Has seven increasing specific levels of classifying organisms ending the binomial nomenclature for each organism.

a.   Kingdom: Broadest grouping of organisms

i.    Six kingdoms:

1)   Archaebacteria (prokaryotes)

2)   Eubacteria (prokaryotes)

3)   Protista (eukaryotes)

4)   Fungi (eukaryotes)

5)   Plantae (eukaryotes)

6)   Animalia (eukaryotes)

b.  Phylum: contains classes with similar characteristics

c.   Class: contains orders with similar characteristics

d.  Order: contains families with similar characteristics

e.   Family: contains genera with similar characteristics

f.    Genus: contains species with similar characteristics

g.   species: contains organisms that look alike and are capable of producing fertile offspring 

B. Two kingdoms contain complex multicellular organisms

1.     Animalia (studied in Zoology)

2.     Plantae (will be studied in Botany)

i.    Characteristics of plants (Kingdom Plantae)

1)   Autotrophic complex multicellular organisms; provide the nutritional foundation for most ecosystems

2)   Cells have a cell wall

3)   Vascular tissue : group of specialized plant cells that transport water and dissolved nutrients

4)   Can not move from place to place (rooted)

5)   Release oxygen into the atmosphere

6)   Cycle phosphorus, water, nitrogen, and carbon

7)   Four basic kinds

a.   Non Vascular – do not have well-developed system of vascular tissue

b.  Seedless Vascular – reproduce using spores

c.  Nonflowering Seed Plants – make seeds but not flowers

d.  Flowering Seed Plants – produce seeds and flowers or fruits

 

1.    Adaptations of Plants

A.  Plants are the dominant group of organisms on land by weight; they are very diverse in size, shape, structure, and function

B.   Plants may have evolved from photosynthetic green algae found in the water, plants had to adapt to life on land by developing specialized structures

1.    Roots - used to obtain water and nutrients, the first roots may have developed from a symbiotic relationship (called mycorrhizae) between the underground parts of plants and fungi, this relationship still exists in 80% of modern plants

2.   Cuticle - water-tight and waxy covering that prevents water loss, covers all non-woody parts of the plants; the stomata are pores in the cuticle that allow for the exchange of gasses; two guard cells border each stoma and change shape to allow the stoma to open and close

3.   Pollen - structures that enclose sperm, allow sperm to be transported without water and prevents them from drying out

C.   Transport of water and nutrients

1.    Vascular plants - use a vascular system of specialized cells arranged in strands that act like a pipeline for nutrients and water

2.   Non-vascular plants - relatively small plants that lack vascular tissue and absorb nutrients and water by osmosis and diffusion

D.  Reproduction by seeds (found in angiosperms and gymnosperms) offers several advantages

1.    Protection - seeds are surrounded by a seed coat that prevents drying, injury, and disease

2.   Nourishment - seeds contain nutrients to feed the embryo as it begins to grow

3.   Plant dispersal - many seeds have structures that allow them to be spread by wind, water, or animals; dispersal limits competition between parents and offspring

4.   Delayed growth - seeds hold the embryo in a state of suspended animation until conditions are favorable for growth

E.   Flowers offer other advantages

1.    Produce both pollen and seeds making reproduction more efficient by reducing the need to use wind as the means of cross-pollination

2.   Attract animals that carry smaller amounts of pollen longer distances than wind

2.   Alternation of Generations (pgs 152 & 524)

A.  Plants reproduce in two phases that alternate

1.    Sporophyte - diploid individual (formed from zygote after fertilization) that produces spores by meiosis  

2.   Gametophyte - haploid individual (formed from spores) that produces gametes by mitosis

B.   Non-vascular plants have a dominant (more noticeable) gametophyte generation

C.   Vascular plants have a dominant (more noticeable) sporophyte generation, marked by several special features

1.    Xylem & Phloem - carry water, minerals, and organic nutrients throughout the plant allowing for growth to great heights

2.   Shoot - upward growing body of the plant

3.   Root - downward growing body of the plant

4.   Meristems - actively dividing plant cells that promote growth

5.   Leaves & stems - grow from the shoot

 

 

How can alternation of generations be observed in the plant kingdom?

 

Non-Vascular Plants - Mosses

moss, labeled

It’s actually easiest to observe alternation of generations in the most primitive group of plants: the mosses. If you’ve ever looked closely at a moss, you may have noticed a tiny leafy green mat from which a stalk protrudes at certain times of the year.

 

The stalk is the sporophyte. From its cap, spores are cast that land on the ground and develop into the gametophyte—the leafy green mat. Special structures within the mat produce sperm and egg. The sperm swim to the eggs and fertilize them. A stalk, which remains attached to the mat, results from each fertilized egg. The moss life cycle thus requires ground water in order to be completed—this is why mosses are always found in moist environments.

Diagram about Alternation of Generations in Moss

Alternation of Generations in Mosses 

 

Seedless Vascular Plants - Ferns

fern with sporangiaAnother major plant group includes the ferns. In ferns, the different generations exist as distinct individuals. The graceful fronds, or leaves, that we see adorn the sporophytes. If you look under the fronds of a mature plant, you’ll see structures where the spores are produced. The spores are cast from these structures onto the ground, where they develop into gametophytes.

 

fern labeledThe gametophytes are tiny heart-shaped structures that are nearly invisible to the naked eye. They require a moist environment to develop and, once mature, produce sperm and egg. Like the mosses, the sperm require water to swim to the eggs, with each fertilized egg developing into the familiar, frond-bearing sporophyte.

Alternation of Generations in Ferns

 

Non-Flowering Seed Plants - Conifers 

In the conifers, the stately needle- and cone-bearing trees are the sporophytes. Conifers actually have two different types of cones. The female cone is probably what you are familiar with, bearing hard, woody scales. In a structure on top coniferof each scale of the female cone, female spores are produced, which develop into the microscopic female gametophyte — a plant that consists of only one cell for most of its existence. The gametophyte remains inside the structure that produced it, which itself remains attached to the scale. 

 

The male cones are much smaller than the female cones and are the structures that produce copious amounts of yellow “dust” in the Spring. On the underside of each tiny scale are structures that produce numerous male spores, which develop into gametophytes that

female cone

consist of just four cells.

 

The gamteophyte and its covering are the pollen, which is carried by wind to the female cone. Pollination occurs when pollen lands at the sticky base of the scale and the sperm grows to and fertilizes an egg, which eventually forms a papery seed on top of the scale. Note that, unlike mosses and ferns, water is not required to bring sex cells together and that the embryo develops in a seed, where it is protected from drying-out and is supplied with food.

 

Alternation of Generations in Gymnosperms 

Flowering Seed Plants

Flowering plants can be used to introduce alternation of generations.  Alternation of generations in flowering plants is essentially the same as in the conifers (and just as complicated), except that flowers represent the sporophyte. Female structures, called ovaries, contain structures that produce the female spores. These develop into a seven-celled gametophyte inside the ovary — you can think of it as a tiny plant inside a plant. The male stuctures, called stamens, produce the pollen. As in the conifers, the male gametophyte develops inside the pollen grain. flower

 

Pollen from the male parts of one flower is delivered to the female parts of another flower in various ways: wind, insects, birds, bats, etc.  When pollination occurs, sperm form and grow to the ovaries, where they fertilize eggs. A fertilized egg develops into a seed inside the ovary. Again, notice that this process does not require water to bring sex cells together, and that a seed protects the developing embryo. The difference between conifers and flowering plants is that the seeds develop within an ovary (the fruit) rather than on top of a cone scale.

 

Alternation of generations in a flowering plant

 

3.   Kinds of Plants

A.  Non-vascular plants

1.    Key Features

a)   Lack a vascular system

b)  Small in size and relatively simple in structure, water and nutrients transported by osmosis and diffusion

c)   Larger gametophyte than sporophyte, have hair-like projections called rhizoids that anchor the gametophytes to the surface on which they grow, sporophytes grow on the gametophyte and depend on them for nutrition

d)  Require water for sexual reproduction, egg and sperm grow in separate structures, often on separate plants, the gametophytes grow in tightly packed mats and sperm swim through a coating of water to reach the eggs

2.   Types

a)   Mosses (phylum Bryophyta)

b)  Liverworts (phylum Hepatophyta)

c)   Hornworts (phylum Anthocerophyta)

 

 

 

B.   Seedless Vascular Plants

1.    Key Features

a)   Do not produce seeds

b)  Have a vascular system with xylem and phloem reinforced with lignin which is a major component in wood; this system allows vascular plants to grow larger and become more complex than non-vascular plants

c)   Sporophytes are larger than gametophytes making it easier for the wind to carry spores increasing dispersal efficiency

d)  Smaller gametophyte develop under the soil and require water for fertilization

e)   Spores are drought resistant and make it possible for a plant to live in drier habitats

2.   Types

a)   Ferns (phylum Pterophyta)

b)  Club Mosses (phylum Lycophyta)

c)   Horsetails (phylum Sphenophyta)

d)  Whisk ferns (phylum Psilotophyta)

   

 


4.   Two types of Seed (Vascular) Plants (Gymnosperms & Angiosperms)

A.  Gymnosperms - seed plants without flowers or fruits to contain seeds

1.    Key Features

a)   Seeds that protect the embryo and provide it with nutrients, allow it to survive adverse conditions, and allow for plant dispersal away from parents

b)  Cones - tiny gametophytes are male or female and form within the sporophyte in male and female cones

c)   Wind pollination - sperm do not need water to travel allowing for pollination in dry conditions

 

Male and Female Pine Cones

 

2.   Types

a)   Conifers (phylum Coniferophyta)

b)  Cycads (phylum Cycadophyta)

c)   Ginko (phylum Ginkophyta)

d)  Gnetophytes (phylum Gnetophyta)

 

 

 

B.   Angiosperms - seed plants with flowers and fruits to contain seeds; the majority of plants are part of this group  

1.    Key Features

a)   Flowers - male and female gametophytes develop within flowers which are more efficient than cones for pollination

b)  Fruits - structures in which the seeds develop, their primary function is seed dispersal

c)   Endosperm - stores of food for the developing embryo as the seed begins to mature

2.   Kinds (two groups)

a)   Monocots - produce seeds with one seed leaf (cotyledon), produce flowers with parts in multiples of three and long narrow leaves with parallel veins

b)  Dicots - produce seeds with two seed leaves (cotyledons), also produce flowers with parts in multiples of two, four or five parts with leaves with branching, netted veins

 

 

 

Monocot Diagram   Dicot Diagram

 

 

 

 5.   Plants Provide Food

A.  Fruits and Vegetables

1.    Classified nutritionally one way, in botany fruits are the reproductive part of the plant which contains seeds, and vegetables are any non-reproductive part of the plant

2.   Both provide dietary fiber and essential vitamins and minerals

B.   Root Crops

1.    Any plant root eaten as food, including carrots, radishes, turnips and beets, these vegetables are enlarged roots that store starch

2.   Potatoes and Yams (sweet potatoes) are also classified as root crops but are actually tubers (modified underground stems that store starch)

C.   Legumes

1.    Members of the pea family

2.    Include soybeans, peas, peanuts, and many types of beans

D.  Cereals

1.    Grasses that produce a large number of dry edible fruit called grains

2.   Includes wheat, corn, rice, oats, & sugar cane

 

 

6.   Plants as Products

A.  Wood/Paper

1.    After food, single most valuable resource obtained from plants

2.   Used in building, producing products like paper and rayon

B.   Medicine

1.    Throughout history plants have been used to treat ailments

2.   Today many of our common and prescription medicines are derived from plants

C.   Fibers

1.    Strands of cellulose from the plant cell body

2.   Used in making cloth, paper, and rope  

D.  Rubber

1.    Made from the sap of the rubber tree called latex

2.   Used in many products including boots, raincoats, and storage devices

 

Supplementary Videos

 


Transpiration

 


Chloroplasts

 


The Leaf Adaptation for Photosynthesis

 


Plant Phylogeny and Alternation of Generations

 


Alternation of Generations Mosses

 


Alternation of Generations Ferns

 

 

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