plants, fungi, and the move onto land - arizona state...

1

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

PowerPoint® Lecture Slides forEssential Biology, Second Edition & Essential Biology with Physiology

Neil Campbell, Jane Reece, and Eric Simon

Presentation prepared by Chris C. Romero

CHAPTER 16CHAPTER 16

Plants, Fungi, and the Move onto LandFigures 16.1 – 16.5


• Some giant sequoia trees weigh more than a dozen space shuttles

• Flowering plants such as corn, rice, and wheat provide nearly all our food.


• A mushroom is probably more closely related to humans than it is to any plant

• Every 2 seconds humans destroy an area of tropical rain forest equal to the area of 3 football fields.

2


• Coniferous forests are highly productive

BIOLOGY AND SOCIETY:

THE BALANCING ACT OF FOREST CONSERVATION

– They provide lumber for building and wood pulp for paper.


• Our demand for wood and paper is so great that clear-cut areas have become commonplace.

Figure 16.1


• The loss of coniferous forests

– Threatens the trees and other organisms that live in forests

– Can be minimized by conservation practices.

3


• Plants

COLONIZING LAND

– Are terrestrial organisms

– Are multicellular eukaryotes that make organic molecules by photosynthesis.


• Living on land poses different problems from living in water

Terrestrial Adaptations of PlantsStructural Adaptations

– Plants require structural specializations

– Roots and shoots.


Figure 16.2

PlantLeafperforms photosynthesis

Cuticlereduces water loss; stomata allow gas exchange

Shootsupports plant (and may perform photosynthesis)

Alga Surrounding water supports the alga

Whole algaperformsPhoto-synthesis;absorbs

water, CO2,and mineralsfrom the water

Rootsanchor plant;absorb water and mineralsfrom the soil (aided by fungi)

4


• Most plants have mycorrhizae, symbiotic fungi associated with their roots.

Figure 16.3


• Leaves

– Are the main photosynthetic organs of most plants

– Have stomata for gas exchange

– Contain vascular tissue for transporting vital materials.

Figure 16.4


• Other types of vascular tissue are found in the roots and shoots of plants.

5


• Plants produce their gametes in protective structures called gametangia.

Reproductive Adaptations


• In plants, but not algae, the zygote develops into an embryo while still contained within the female parent.


Figure 16.5

Ovary of flower

Embryo

Maternal tissue

6


The Origin of Plants from Green Algae

• The move onto land and the spread of plants to diverse terrestrial environments were incremental


• Molecular comparisons and other evidence place a group of green algae called charophyceans closest to plants.

Figure 16.6


• The history of the plant kingdom is a story of adaptation to diverse terrestrial habitats.

PLANT DIVERSITY

7


Highlights of Plant Evolution

• The fossil record chronicles four major periods of plant evolution.


Figure 16.7

Cen

ozo

icM

esoz

oic

Pal

eozo

ic Ch

arop

hyc

ean

s (a

gro

up

of

gre

en a

lgae

)

Bry

oph

ytes

(e.

g.,

mos

ses)

See

dle

ss v

ascu

lar

pla

nts

(e

.g.,

fern

s)

Gym

nos

per

ms

(e.g

., co

nife

rs)

An

gio

-sp

erm

s

Origin of plants

Early vascular plants

First seed plants

Diversification of flowering plants


• The first period

– Was the origin of plants from their aquatic ancestors, charophyceans

• The second period

– Was the diversification of vascular plants

8


• The third period

– Began with the origin of the seed

• The fourth period

– Was the emergence of flowering plants, or angiosperms.


Bryophytes

• Mosses

Figure 16.8

– Are the most familiar bryophytes.


• Mosses display two key terrestrial adaptations

– A waxy cuticle that helps prevent dehydration

– The retention of developing embryos within the mother’s gametangium.

9


• Mosses have two distinct versions of the plant

– The gametophyte, which produces gametes

– The sporophyte, which produces spores.

Figure 16.9


• The life cycle of a moss exhibits an alternation of generations.


Figure 16.10

Sporesn Mito

sis

Sporophyte2n

Mitosis

Gametes (sperm and

eggs)n

Fertilization

Zygote2n

Mitosis

Spore capsule

Meiosis

Gametophyten

Haploid

Diploid

10


Ferns

• Ferns

Figure 16.11

– Are seedless vascular plants.


• During the Carboniferous period, about 290–360 million years ago, ferns formed swampy forests that covered much of what is now Eurasia and North America

– These forests formed what would become fossil fuels.

Figure 16.12


Gymnosperms

• A drier, colder climate at the end of the Carboniferous period favored the evolution of gymnosperms, the first seed plants.

11


• Conifers

Conifers

– Cover much of northern Eurasia and North America

– Are usually evergreens, which retain their leaves throughout the year.

Figure 16.13


• Conifers and most other gymnosperms have three terrestrial adaptations

Terrestrial Adaptations of Seed Plants

– Further reduction of the gametophyte

– The evolution of pollen

– The advent of the seed.


• The first adaptation is a greater development of the diploid sporophyte compared to the haploid gametophyte generation.

12


Figure 16.14

Gametophyte (n)

Sporophyte (2n)

(a) Sporophytedependent on gametophyte (e.g., mosses)

Sporophyte (2n)

Gametophyte (n)

(b) Large sporophyte and small, independent gametophyte (e.g., ferns)

Sporophyte (2n)

Gametophyte (n)

(c) Reduced gametophyte dependent on sporophyte (seed plants)

Haploid (n)

Diploid (2n)


• A pine tree of other conifer is actually a sporophyte with tiny gametophytes living in cones.

Figure 16.15


• A second adaptation of seed plants to dry land was the evolution of pollen

• A pollen grain

– Is actually the much-reduced male gametophyte

– Fertilizes the female gametophyte.

13


• The third terrestrial adaptation was the development of the seed

• A seed consists of a plant embryo packaged along with a food supply within a protective coat.

Figure 16.16

Integuments

Spore

(a) Ovule

Haploid (n)

Diploid (2n)

Pollen tube

Pollen grain(male gametophyte)

Female gametophyte

Egg nucleus

Discharged sperm nucleus

(b) Fertilized ovule

Seed coat (derived from integuments)

Food supply (derived from female gametophyte tissue)

Spore case

Embryo(new sporophyte)

(c) Seed


Angiosperms

• Angiosperms

– Supply nearly all our food and much of our fiber for textiles

• More efficient water transport and the evolution of the flower help account for the success of the angiosperms.


• The dominant stage of the angiosperms is a sporophyte with gametophytes in its flowers.

Flowers, Fruits, and the Angiosperm Life Cycle

14


Figure 16.17

Stamen

Anther

Filament

Ovule

Petal

CarpelStigma

Style

Ovary

Sepal


• The life cycle of an angiosperm.


Mature sporophyteplant with flowers

Germinated pollen grain (male gametophyte) on stigma of carpel

Anther at tip of stamen

Pollen tube growing down style of carpel

Ovary (base of carpel)

Embryo sac (female gametophyte)

Egg

Sperm nuclei

Fertilization

Endosperm

Zygote

Embryo (sporophyte)

Fruit (develops from ovary)

Seed (develops from ovule)

Seed

Germinating seed

Sporophyte seedling

Haploid (n)

Diploid (2n)

Ovule

Figure 16.18

15


• The seed being enclosed within an ovary distinguishes angiosperms from gymnosperms.


• A fruit

– Is a ripened ovary

– Helps protect the seed and increase seed dispersal

– Is a major food source for animals.

Figure 16.19


• Angiosperms

Angiosperms and Agriculture

– Supply fiber, medications, perfumes, and decoration

• Agriculture

– Is a unique kind of evolutionary relationship between plants and animals.

16


Plant Diversity as a Nonrenewable Resource

• The exploding human population is extinguishing plant species at an unprecedented rate.


• Humans depend on plants for thousands of products including food, building materials, and medicines.


Table 16.1

17


• Preserving plant diversity is important to many ecosystems as well as humans.


• Fungi are extremely important to ecosystems because they decompose and recycle organic materials.

FUNGI


• Fungi

– Are eukaryotes, and most are multicellular

– Are more closely related to animals than plants.

18


• A gallery of diverse fungi

Figure 16.20


Characteristics of Fungi

• In this section, the structure and function of fungi are described.


• Fungi are heterotrophs

Fungal Nutrition

– They digest their food externally and acquire the nutrients by absorption.

19


• The bodies of most fungi are constructed of structures called hyphae.

Fungal Structure


• The hyphae

– Form an interwoven mat called a mycelium

– Are separated into cells by cross-walls made mainly of chitin.


Figure 16.21

Hyphae

Reproductive structure

Spore-producing structures

Mycelium

20


• Fungi reproduce by releasing spores that are produced either sexually or asexually.

Fungal Reproduction


The Ecological Impact of Fungi

• Fungi

– Have an enormous ecological impact.


• Fungi and bacteria

Fungi as Decomposers

– Are the principal decomposers of ecosystems

– Keep ecosystems stocked with nutrients necessary for plant growth.

21


• Molds

– Can destroy fruit, wood, and human-made materials.


• Of the 100,000 known species of fungi, about 30% make their living as parasites.

Parasitic Fungi

Figure 16.22


• About 50 species of fungi are known to be parasitic in humans and other animals.

22


• Fungi are commercially important

Commercial Uses of Fungi

– As food and in baking

– In beer and wine production.

Figure 16.23


• Some fungi produce antibiotics.

Figure 16.24


• Interdependence between species, or symbiosis, is an evolutionary product

EVOLUTION CONNECTION:

MUTUAL SYMBIOSIS

– Mutualism is symbiosis that benefits both species.

23


• Lichens

– Are symbiotic associations between fungi and algae.

Figure 16.25


SUMMARY OF KEY CONCEPTS

Visual Summary 16.1

Leaves are main photosynthetic organs

Gametangia protect gametes from dehydration; female gametangia protect developing embryos

Cuticle reduces water loss

Stomata allow gas exchange between plant and atmosphere

Lignin hardens cell walls

Shoot supports plant; may perform photosynthesis

Vascular tissues transport water, minerals, and sugars; provide support

Roots anchor plant; mycorrhizae(root/fungus associations) help absorb water and minerals from the soil)

• Terrestrial Adaptations of Plants.


• Highlights of Plant Evolution.

Visual Summary 16.2

Origin of gametangia

(protect gametes and

embryos)

Diversification of seedless

vascular plants (vascular tissue conducts water and nutrients)

Origin of seeds (protect embryos from desiccation

and other hazards)

Origin of flowers (bear ovules

within protective chambers called

ovaries)

plants, fungi, and the move onto land - arizona state...

Documents