biol 108 chp 12 plant and fungi diversification
TRANSCRIPT
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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