Embed Size (px)
Citation preview
End Show
Slide
1 of 33
Biology
Copyright Pearson Prentice Hall
Chapter 22.1
What is a Plant?
End Show
Slide
2 of 33
Objectives
Copyright Pearson Prentice Hall
1. Describe the basic characteristics of
life .
2. Describe what plants need to
survive.
3. Describe the life cycle of plants.
4. Describe how the first plants
evolved.
End Show
22–1 Introduction to Plants
Slide
3 of 33
Copyright Pearson Prentice Hall
What Is a Plant?
What Is a Plant?
Plants are multicellular eukaryotes that
have cell walls made of cellulose.
Plants develop from multicellular embryos
and carry out photosynthesis using the
green pigments chlorophyll a and b.
End Show
22–1 Introduction to Plants
Slide
4 of 33
Copyright Pearson Prentice Hall
What Is a Plant?
• Plants include trees, shrubs, and grasses, as well
as other organisms, such as mosses and ferns.
• Most plants are autotrophs, although a few are
parasites or saprobes that live on decaying
materials.
End Show
22–1 Introduction to Plants
Slide
5 of 33
Copyright Pearson Prentice Hall
The Plant Life Cycle
The Plant Life Cycle
• Plant life cycles have two alternating phases, a
diploid (2N) phase and a haploid (N) phase,
known as alternation of generations.
End Show
22–1 Introduction to Plants
Slide
6 of 33
Copyright Pearson Prentice Hall
The Plant Life Cycle
• Alternation
of
Generations
End Show
22–1 Introduction to Plants
Slide
7 of 33
Copyright Pearson Prentice Hall
What Plants Need to Survive
What do plants need to survive?
End Show
22–1 Introduction to Plants
Slide
8 of 33
Copyright Pearson Prentice Hall
What Plants Need to Survive
In order to survive, plants need:
• sunlight
• water and minerals
• gas exchange
• transport of water and nutrients
throughout the plant body
End Show
22–1 Introduction to Plants
Slide
9 of 33
Copyright Pearson Prentice Hall
What Plants Need to Survive
Sunlight
• Plants use energy
from sunlight to
carry out
photosynthesis.
• Photosynthetic
organs such as
leaves are broad
and flat to
maximize light
absorption.
End Show
22–1 Introduction to Plants
Slide
10 of 33
Copyright Pearson Prentice Hall
What Plants Need to Survive
Water and Minerals
• All cells require a constant supply of water.
• Water is used up quickly when the sun is
shining. As a result, plants have structures that
limit water loss.
End Show
22–1 Introduction to Plants
Slide
11 of 33
Copyright Pearson Prentice Hall
What Plants Need to Survive
• As they absorb water, plants also absorb minerals.
• Minerals are nutrients in the soil needed for plant
growth.
End Show
22–1 Introduction to Plants
Slide
12 of 33
Copyright Pearson Prentice Hall
What Plants Need to Survive
Gas Exchange
• Plants require oxygen to support cellular
respiration as well as carbon dioxide to carry
out photosynthesis.
• They must exchange these gases with the
atmosphere without losing excessive amounts
of water through evaporation.
Is like your lungs,
nose and mouth
End Show
22–1 Introduction to Plants
Slide
13 of 33
Copyright Pearson Prentice Hall
What Plants Need to Survive
Movement of Water and Nutrients
• Plants take up water and minerals through their
roots, but they make food in their leaves.
• Most plants have specialized tissues that carry
water and nutrients from the soil and distribute
products of photosynthesis throughout the plant
body.
• Simpler plants carry out these functions by
diffusion.
End Show
22–1 Introduction to Plants
Slide
14 of 33
Copyright Pearson Prentice Hall
Early Plants
Early Plants
• When plants first appeared, life on Earth
changed.
• As plants colonized the land, they changed the
environment so other organisms could develop.
• New ecosystems arose, and organic matter
began to form soil.
End Show
22–1 Introduction to Plants
Slide
15 of 33
Copyright Pearson Prentice Hall
Early Plants
How did the first plants evolve?
End Show
22–1 Introduction to Plants
Slide
16 of 33
Copyright Pearson Prentice Hall
Early Plants
The first plants evolved from an organism
similar to the multicellular green algae
living today.
End Show
22–1 Introduction to Plants
Slide
17 of 33
Copyright Pearson Prentice Hall
Early Plants
• Multicellular green algae have the size, color, and
appearance of plants.
• They have reproductive cycles similar to those of
plants.
• Green algae also have
• cell walls made of cellulose
• and photosynthetic pigments that are identical
to those of plants.
End Show
22–1 Introduction to Plants
Slide
18 of 33
Copyright Pearson Prentice Hall
Early Plants
The First Plants
• DNA sequences confirm that plants are closely
related to certain groups of green algae,
suggesting that the ancestors of the first plants
were indeed algae.
End Show
22–1 Introduction to Plants
Slide
19 of 33
Copyright Pearson Prentice Hall
Early Plants
• The oldest known plant fossils, about 450 million
years old, are similar to today’s mosses.
• They had a simple structure and grew close to the
ground.
End Show
22–1 Introduction to Plants
Slide
20 of 33
Copyright Pearson Prentice Hall
Early Plants
Fossils suggest that the first plants needed water to
complete their life cycles.
The demands of life on land favored the evolution of
plants that were:
• more resistant to the drying rays of the sun.
• more capable of conserving water.
• more capable of reproducing without water.
End Show
22–1 Introduction to Plants
Slide
21 of 33
Copyright Pearson Prentice Hall
Early Plants
From these plants, several major groups of plants
evolved.
• One group developed into the mosses and their
relatives.
• Another group gave rise to all other plants.
All plants have evolved different adaptations for a variety of terrestrial environments.
End Show
22–1 Introduction to Plants
Slide
22 of 33
Copyright Pearson Prentice Hall
Overview of the Plant Kingdom
Overview of the Plant Kingdom
Plants are divided into four groups based on these
features:
• water-conducting tissues
• seeds
• flowers
Plants are also classified by other features,
including reproductive structures and body plan.
End Show
22–1 Introduction to Plants
Slide
23 of 33
Copyright Pearson Prentice Hall
Overview of the Plant Kingdom
Evolutionary Relationships Among Plants
Flowering plants
Cone-bearing plants
Ferns and
their relativesMosses and
their relatives
Flowers; Seeds
enclosed in fruit
Water-conducting (vascular)
tissue
Seeds
Green algae
ancestor
End Show
22–1 Introduction to Plants
Slide
24 of 33
Copyright Pearson Prentice Hall
Overview of the Plant Kingdom
• Today, scientists can classify plants more precisely
by comparing the DNA sequences of various
species.
End Show
- or -
Continue to: Click to Launch:
Slide
25 of 33
Copyright Pearson Prentice Hall
22–1
End Show
Slide
26 of 33
Copyright Pearson Prentice Hall
22–1
Most plants alive today are
a. cone-bearing.
b. flowering.
c. ferns.
d. mosses.
End Show
Slide
27 of 33
Copyright Pearson Prentice Hall
22–1
The two phases of a plant's life cycle are
referred to as
a. alternation of generations.
b. spontaneous generation.
c. biogenesis.
d. sexual and asexual.
End Show
Slide
28 of 33
Copyright Pearson Prentice Hall
22–1
Which statement accurately describes a way that plants meet their basic needs?
a. Plants take in carbon dioxide from soil through their roots.
b. Plants obtain the energy for photosynthesis from sunlight.
c. Plants obtain minerals by exchanging gases with the atmosphere.
d. Plants absorb water through their broad, flat leaves.
End Show
Slide
29 of 33
Copyright Pearson Prentice Hall
22–1
The first group of plants to evolve from green
algae were the
a. cone-bearing plants.
b. ferns.
c. mosses.
d. flowering plants.
End Show
Slide
30 of 33
Copyright Pearson Prentice Hall
22–1
The diploid phase of the plant life cycle is known
as the
a. sporophyte.
b. gametophyte.
c. egg.
d. spore.
END OF SECTION
