Diversification of the Plants

and Fungi

BIOL 108 Intro to Bio Sci

Chapter 12 Part 2

Rob Swatski Asst Prof Biology

HACC-York

12.9 A flower is nothing without a pollinator.

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Why are flowers so flashy?

Trickery and Bribery

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1) Trickery

Plant deceit!

Orchid species

• flowers that resemble female wasps

• Male wasps “riding a bucking bronco”

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2) Bribery

Plants offer something of value for pollen transport.

Requires:

a) a sticky pollen

b) a flower that catches the attention of the pollinator

c) something of value to the pollinator.

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Which answer below is an example of coevolution between two species?

1. A flower gets pollinated through wind dispersal.

2. Seeds get dispersed by sticking to passing animals.

3. A flower develops into a fruit for animals to eat.

4. Yucca moths can only enter yucca plant flowers that provide a place for the moths to lay their eggs.

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Take-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.

Flowers are conspicuous structures that advertise

their presence with colors, patterns, movements, and

odors.

Based on these structures, 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

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Two 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

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Do flowers fertilize themselves?

Outbreeding versus Inbreeding

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What is an advantage of double fertilization in angiosperms?

1. Production of endosperm

2. Larger seeds

3. Increase in energy used to make the seed

4. 1 and 2

5. All of the above

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Take-Home Message 12.10

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.

The formation of a pollen tube allows angiosperms to

ensure that only pollen from a different individual

can fertilize the female gamete.

This ensures greater genetic variation among offspring than through inbreeding.

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12.11 Fleshy fruits are bribes that flowering plants pay animals to

disperse seeds.

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How does this system work?

Fruits are colorful.

Fruits taste good.

Fruit is good for animals.

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Can seeds still sprout after being eaten by an animal?

Test it yourself!

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Take-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.

Fruits are made up from the ovary and, occasionally some

surrounding tissue.

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12.12 Unable to escape, plants must resist predation in other

ways.

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Chemical Defenses as Medicines?

Medicinal plants

Salicin, opium, digitalin, ipecac

Bioprospecting

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Insect Attack!

Volatile chemicals

Plants can also warn nearby plants!

• methyl jasmonate (MeJa)

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How do animals help plants?

1. Animals eat plant leaves, stems, and roots.

2. Animals can provide nitrogen.

3. Predation signals plants to produce MeJa.

4. Plants produce alkaloids in response to predation.

5. 1 and 2

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Take-Home Message 12.12

Plants have a wide range of defenses against herbivorous

animals: physical defenses like 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.

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

insects.

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12.13 Fungi are closer to animals than they are to plants.

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Take-Home Message 12.13

Fungi are eukaryotes with one distinctive feature—a cell wall formed by a protein

called chitin.

Some fungi, called yeasts, live as individual

cells; most others are multicellular.

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12.14 Fungi have common structures, but exploit an

enormous diversity of habitats.

What is a “mycelium”?

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Mushroom Delicacies

Portobello and shitake mushrooms

The white button mushroom on pizza

Truffles

• sell for $1750 to $3500 per pound!

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How can fungi grow in so many habitats?

Advantages of being a decomposer

Fungi don’t need light

Hyphae

Enormously important ecological role!

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Fungal Invasion!

Sick-building Syndrome

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Fungal Parasites

On humans?!

Mycosis

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Lichens

Fungi and chlorophyll-containing bacteria and algae as “partners”

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How are fungi and plants similar?

1. Both are sessile.

2. Both use photosynthesis to produce food.

3. Both use chitin for building cell walls.

4. Both have a dikaryotic state in their life cycle.

5. Both have a prominent multicellular haploid state in their life cycle.

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Take-Home Message 12.14

Fungi are decomposers, and all they need to thrive is

organic material to consume and a moist environment so their hyphae don't dry out.

Fungi can grow almost anywhere that is moist, and they can attain enormous

sizes.

Fungi have complex life cycles, with both sexual and asexual phases; the parts of

fungi that are most often visible are their temporary

spore-producing bodies.

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12.15 Most plants have fungal symbionts.

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Take-Home Message 12.15

Plants and fungi have a close and mutually beneficial association.

Mycorrhizal fungi grow in intimate association with the roots of most

plants, receiving sugar from the plant and transferring nitrogen and

phosphorus to the plant.

Some plants have turned this relationship into parasitism—these

plants lack chlorophyll so they contribute nothing to the fungus,

but they receive nutrients from the fungus and sugar from other plants

that is delivered via the fungus.

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What is the benefit of the symbiotic relationship (mycorrhyzae) for the fungus and

plant respectively?

1. sugars for the fungus; protection for the plant

2. increased nutrient absorption for the fungus; sugars for the plant

3. sugars for the fungus; increased nutrient absorption for the plant

4. protection for the fungus; increased nutrient absorption for the plant

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