biol 108 chp 12 plant and fungi diversification

Diversification Diversification of the Plants of the Plants

and Fungiand Fungi

BIOL BIOL 108 108 Intro to Bio Intro to Bio SciSci

Chapter Chapter 1212

Rob Rob SwatskiSwatski Assoc Prof BiologyAssoc Prof Biology

HACCHACC--YorkYork

12.1

Plants are

just one

branch of

the eukarya.

12.1 What makes you a plant?12.1 What makes you a plant?

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Most Plants Make Their Own FoodMost Plants Make Their Own Food

Nitrogen, phosphorus, and salts

Roots and shoots

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TakeTake--Home Message 12.1 Home Message 12.1

Plants are multicellular organisms that spend most of their lives anchored to one place by their roots.

Plants are multicellular organisms that spend most of their lives anchored to one place by their roots.

The inability of plants to move shapes the way they

obtain food, reproduce, and protect themselves

from predation.

The inability of plants to move shapes the way they

obtain food, reproduce, and protect themselves

from predation.

Characteristics evolved that made it possible for plants to succeed on land despite their inability to

move.

Characteristics evolved that made it possible for plants to succeed on land despite their inability to

move.

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12.2–12.4

The first

plants had

neither

roots nor

seeds.

12.2 Colonizing land brings 12.2 Colonizing land brings new opportunities and new opportunities and challenges for plants.challenges for plants.

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The First Land Plants Appeared About The First Land Plants Appeared About 475 Million Years Ago475 Million Years Ago

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TakeTake--Home Message 12.2 Home Message 12.2

The first land plants were small and had no leaves,

roots or flowers and could grow only at the

water’s edge.

The first land plants were small and had no leaves,

roots or flowers and could grow only at the

water’s edge.

These inconspicuous little plants set the stage for

the enormous diversity of terrestrial plants and

animals on earth today.

These inconspicuous little plants set the stage for

the enormous diversity of terrestrial plants and

animals on earth today. 13

12.3 Mosses and other non12.3 Mosses and other non--vascular plants lack vessels for vascular plants lack vessels for

transporting nutrients and transporting nutrients and water.water.

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Alternation of GenerationsAlternation of Generations

A life cycle of alternating haploid and diploid generations in which the diploid embryo is protected by the haploid female

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TakeTake--Home Message 12.3 Home Message 12.3

Non-vascular plants—mosses, liverworts, and hornworts—

have scarcely evolved beyond the stage of the earliest land

plants.

Non-vascular plants—mosses, liverworts, and hornworts—

have scarcely evolved beyond the stage of the earliest land

plants.

They lack roots and vessels to move water and nutrients

from the soil into the plant.

They lack roots and vessels to move water and nutrients

from the soil into the plant.

They reproduce with spores that form when a sperm from a male reproductive structure

“swims” through a drop of rainwater to the egg in a

female reproductive structure.

They reproduce with spores that form when a sperm from a male reproductive structure

“swims” through a drop of rainwater to the egg in a

female reproductive structure.

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12.4 The evolution of vascular 12.4 The evolution of vascular tissue made large plants tissue made large plants

possible.possible.

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TakeTake--Home Message 12.4 Home Message 12.4

Vessels are an effective “circulatory system” to carry water and nutrients up from the soil to a plant’s leaves.

Vessels are an effective “circulatory system” to carry water and nutrients up from the soil to a plant’s leaves.

The first vascular plants—including the earliest ferns and horsetails—were able to grow much taller than

their non-vascular predecessors.

The first vascular plants—including the earliest ferns and horsetails—were able to grow much taller than

their non-vascular predecessors.

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12.5–12.7

The advent of the

seed opened new

worlds to plants.

12.5 What is a seed?12.5 What is a seed?

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Seeds Are Goodbye GiftsSeeds Are Goodbye Gifts

• DNA, RNA, a few proteins

• A multicellular embryo and a store of nutrients

• Endosperm

• Gymnosperms and angiosperms

How are seeds formed?How are seeds formed?

The gametophyte • a life stage that produces haploid gametes

Pollen grains and ovules • Pollen produces a pollen tube that grows into the

ovule.

The external layer of the ovule forms the seed coat.

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Seed DispersalSeed Dispersal

Only opportunity most plants have to send their offspring away from home

Seeds and seed pods have many ways to do this:

• forceful send-off of exploding seed pods

• seeds that hitch rides on passing animals

• seeds that float in water or almost fly

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TakeTake--Home Message 12.5 Home Message 12.5

Seeds are the way plants give their

offspring a good start in life and get them to

leave home.

Seeds are the way plants give their

offspring a good start in life and get them to

leave home.

A seed contains a multicellular embryo of the plant, plus a store of carbohydrate and

nutrients.

A seed contains a multicellular embryo of the plant, plus a store of carbohydrate and

nutrients.

Seeds are distributed by wind, animals, or

water.

Seeds are distributed by wind, animals, or

water.

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12.6 With the evolution of the 12.6 With the evolution of the seed, gymnosperms became the seed, gymnosperms became the

dominant plants on Earth.dominant plants on Earth.

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TakeTake--Home Message 12.6 Home Message 12.6

Gymnosperms (pine trees and their relatives) were the earliest

plants to produce seeds.

Gymnosperms (pine trees and their relatives) were the earliest

plants to produce seeds.

This mode of reproduction offered advantages over the

spores of earlier plants and gave gymnosperms the boost they

needed to become the dominant plants of the early and middle

Mesozoic era.

This mode of reproduction offered advantages over the

spores of earlier plants and gave gymnosperms the boost they

needed to become the dominant plants of the early and middle

Mesozoic era.

Gymnosperms depend on wind to carry their pollen—not an efficient method of dispersal.

Gymnosperms depend on wind to carry their pollen—not an efficient method of dispersal.

Conifers protect the developing seeds in the female cone.

Conifers protect the developing seeds in the female cone.

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12.7 Conifers include the 12.7 Conifers include the tallest and longesttallest and longest--living living

trees.trees.

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How can trees grow large and live to How can trees grow large and live to great ages?great ages?

Woody plants can be exceptionally strong and resistant to attack by herbivores

Heartwood

Bark

Exuding a sticky pine pitch

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TakeTake--Home Message 12.7 Home Message 12.7

Conifers are the success stories among gymnosperms, with more species and a larger geographic range than all of their relatives

combined.

Conifers are the success stories among gymnosperms, with more species and a larger geographic range than all of their relatives

combined.

Rigidity, an exterior layer of bark, and the ability to exude sticky pitch protects conifers, helping make it possible for conifers to

grow taller and reach older ages than any other plants.

Rigidity, an exterior layer of bark, and the ability to exude sticky pitch protects conifers, helping make it possible for conifers to

grow taller and reach older ages than any other plants.

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12.8–12.10

Flowering

plants are

the most

diverse and

successful

plants.

12.8 Angiosperms are the dominant 12.8 Angiosperms are the dominant plants today.plants today.

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TakeTake--Home Message 12.8 Home Message 12.8

Flowering plants appeared in the Cretaceous period, about 100

million years ago, and diversified rapidly to become the dominant

plants in the modern world.

Flowering plants appeared in the Cretaceous period, about 100

million years ago, and diversified rapidly to become the dominant

plants in the modern world.

A flower houses a plant’s reproductive structures, and

most flowers have both male and female structures, although

some flowers have only male or only female reproductive

structures.

A flower houses a plant’s reproductive structures, and

most flowers have both male and female structures, although

some flowers have only male or only female reproductive

structures. 44

12.9 A flower is nothing without a pollinator.

Why are flowers so flashy?

Trickery and Bribery

TakeTake--Home Message 12.9 Home Message 12.9

Angiosperms have found a way to transfer pollen

efficiently from the anthers of one flower to the stigma of another—let an animal

carry it.

Angiosperms have found a way to transfer pollen

efficiently from the anthers of one flower to the stigma of another—let an animal

carry it.

Flowers are conspicuous structures that advertise

their presence with colors, patterns, movements, and

odors.

Flowers are conspicuous structures that advertise

their presence with colors, patterns, movements, and

odors.

Using these devices, plants are able to trick or bribe animals into transporting male gametes to female

gametes, where fertilization can occur.

Using these devices, plants are able to trick or bribe animals into transporting male gametes to female

gametes, where fertilization can occur.

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12.10 Angiosperms improve seeds with double fertilization.

An embryo + a substantial, ready-made food source

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What advantage does double fertilization give to angiosperms?

Two Important Advantages

Two Advantages of Double FertilizationTwo Advantages of Double Fertilization

Initiates formation of endosperm only when an egg is fertilized

Smaller gametes can be produced.

• Ensures that seeds are produced quickly

TakeTake--Home Message 12.10 Home Message 12.10

Angiosperms undergo a process called double

fertilization.

Angiosperms undergo a process called double

fertilization.

Double fertilization ensures that a plant does not invest

energy in forming endosperm for an ovule

that has not been fertilized.

Double fertilization ensures that a plant does not invest

energy in forming endosperm for an ovule

that has not been fertilized. 55

12.11–12.12 Plants and

animals have a love-hate

relationship.

12.11 Fleshy fruits are bribes that 12.11 Fleshy fruits are bribes that flowering plants pay animals to flowering plants pay animals to

disperse seeds.disperse seeds.

How does this system work?How does this system work?

Fruits are colorful.

Fruits taste good.

Fruit is good for animals.

Can seeds still sprout after being eaten by an animal?

Test it yourself!

TakeTake--Home Message 12.11 Home Message 12.11

Plants often use the assistance of animals to disperse their

fruits (containing seeds), depositing them at a new

location where they can grow.

Plants often use the assistance of animals to disperse their

fruits (containing seeds), depositing them at a new

location where they can grow.

Fruits are made up from the ovary and, occasionally some

surrounding tissue.

Fruits are made up from the ovary and, occasionally some

surrounding tissue.

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12.12 Unable to escape, plants 12.12 Unable to escape, plants must resist predation in other must resist predation in other

ways.ways.

Chemical Defenses as Medicines?Chemical Defenses as Medicines?

Medicinal plants

Salicin, opium, digitalin, ipecac

Bioprospecting

Insect Attack!Insect Attack!

Volatile chemicals

Plants can also warn nearby plants!

• Methyl jasmonate (MeJa)

TakeTake--Home Message 12.12 Home Message 12.12

Plants have a wide range of defenses against herbivorous

animals: physical defenses such as thorns and chemicals, which have complex effects on

the physiology of animals.

Plants have a wide range of defenses against herbivorous

animals: physical defenses such as thorns and chemicals, which have complex effects on

the physiology of animals.

Plants respond to insect attack by synthesizing chemicals that

make the plant that is being eaten less palatable.

Plants respond to insect attack by synthesizing chemicals that

make the plant that is being eaten less palatable.

Some plants living in soil that is deficient in nitrogen have switched roles, preying on

insects.

Some plants living in soil that is deficient in nitrogen have switched roles, preying on

insects.

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