Download 2. Maintaining mechanisms of biodiversity

The Futurability of Biodiversity Chapter 2
Why have the earth’s organisms become so diverse?
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
In review
Biodiversity＝Gathering of organisms with interactions
Ecosystems whose biodiversity is high enrich
human life - for example, providing various
foods or medicines, keeping diseases in
check, affecting local culture, and so on.
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
Today’s Topics
1. Evolution of biodiversity
How has the present biodiversity of the earth evolved?
2. Maintaining mechanisms of biodiversity
How is the present biodiversity of the earth maintained?
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
1. Evolution of biodiversity
 How has the present biodiversity of the earth
evolved?
1. Biological evolution
2. Environmental factors of evolution
Isolation & Niche
3. Ecological factors of evolution
Coevolution & Cospeciation
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1. Evolution of biodiversity 1) Biological evolution
What is the ancestor of dogs?
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1. Evolution of biodiversity 1) Biological evolution
Evolutionary history
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1. Evolution of biodiversity 2) Environmental factors of evolution
Isolation
Bat
Lion
Elephant
Mole
Koala
Primitive mammal
Camel
Reindeer
Deer
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Whale
1. Evolution of biodiversity 2) Environmental factors of evolution
Niche
arboreal
terrestrial
hypogeal
aquatic
herbivorous
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carnivorous
1. Evolution of biodiversity 2) Environmental factors of evolution
Herbivorous and terrestrial mammals
Desert
Foraging method Temperate
zone
Big body
Arctic
zone
There are few animals which live in the
same environmental conditions with the
same habitat.
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1. Evolution of biodiversity 3) Ecological factors of evolution
Coevolution
Herbivores
Mustard oil
CH2=CHCH2N=C=S
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1. Evolution of biodiversity 3) Ecological factors of evolution
These new
Insects eat
the plant.
new
Some insects have evolutionarily
acquired the metabolic mechanism
which detoxicates the chemical.
new
The plant synthesizes
a poisonous chemical.
Both plants and animals continue to evolve, affected
by a vicious circle (arm’s race).
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1. Evolution of biodiversity 3) Ecological factors of evolution
Mutualism means …
close interaction between organisms
which help each other.
This is not the truth!
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1. Evolution of biodiversity 3) Ecological factors of evolution
The process of establishing pollinative mutualism
―The true aspect of mutualism―
1. Insects were initially herbivores (enemies of plants).
Oh no!
Our flowers will be eaten!
I’m hungry.
Oh!
I found food!
Food
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
1. Evolution of biodiversity 3) Ecological factors of evolution
The process of establishing pollinative mutualism
―The true aspect of mutualism―
2. Some flowers have evolved to secrete nectar.
Continuously produced nectar is
better food than flowers, isn’t it?
えさ
Nectar
Pollination
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That’s true.
Oh! It’s so sweet!
I will come here again.
1. Evolution of biodiversity 3) Ecological factors of evolution
The process of establishing pollinative mutualism
―The true aspect of mutualism―
3. Plants make the insects pollinate.
Give me nectar.
I have collected nectar
from other flowers like
you, but I need more!
Yes, of course.
(We did it ! She will pollinate.)
Nectar
Pollination
Mutualism is the result of evolution whereby a species has tried
for a long time to take advantage of the other species, which
was originally hostile.
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1. Evolution of biodiversity 3) Ecological factors of evolution
Partnerships between flowers and pollinators
Characteristics
of flower
?
Color
Uniqueness
Time zone of
providing nectar
White
Strong
smell
Night
Yellow
Large
number
of
flowers
Daytime
Red
Tubulous
flower
Daytime
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Pollinator
Summary 1. Evolution of biodiversity
 Biodiversity is the result of evolution.
The present biodiversity on the earth is the evolutionary state
still in progress.
Evolution is promoted by isolation, such as continental drift.
Life history varies from species to species, caused by
adaptations to different niches.
Interspecific interaction also promotes evolution.
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
2. Maintaining mechanisms of biodiversity
 How is the present biodiversity of the earth
maintained?
1. Segregation of niche
space, time and food
2. Fixation of interspecific interaction
Cospeciation and host-shift
3. Keystone species
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
2. Maintaining mechanisms of biodiversity
1) Segregation of niche
Spatial segregation of ant species inhabiting
tropical rainforest, Southeast Asia
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2. Maintaining mechanisms of biodiversity
1) Segregation of niche
Temporal segregation
Diurnal species
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Nocturnal species
2. Maintaining mechanisms of biodiversity
1) Segregation of niche
Food segregation
(South America)
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
2. Maintaining mechanisms of biodiversity
1) Segregation of niche
Segregation of niche in ant community
Carnivorous
Herbivorous
Several species which inhabit the same place coexist by
segregation of niche.
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2. Maintaining mechanisms of biodiversity 2) Cospeciation and host-shift
Mutualism between Macaranga species and
Crematogaster ants
Nesting space
(hollow stem)
Food bodies (food)
Protection against
herbivores
(bodyguard)
Macaranga
sp.
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Crematogaster
ants
Photo: (right) Tamiji Inoue
2. Maintaining mechanisms of biodiversity 2) Cospeciation and host-shift
When mutualistic ants are experimentally removed…
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2. Maintaining mechanisms of biodiversity 2) Cospeciation and host-shift
Sharing the same fate started diversification
Molecular phylogeny of Crematogaster ant and Macaranga spp.
Crematogaster
ant
C. borneensis1
M. trachyphylla
Macaranga spp.
M. bancana
C. borneensis2
M. hullettii
C. decamera1
M. havilandii
Host-shift
C. decamera2
C. sp.4
M. lamellata
M. beccariana
M. hypoleuca
M. hosei
C. sp.2
M. Winkler
The above partnerships are species-specific.
Fixation of the partnerships = survival of each species
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(Itino et al. 2001)
2. Maintaining mechanisms of biodiversity
3) Keystone species
Is any species indispensable to maintaining ecosystem?
Keystone species
Excessive hunting
of sea otters in
1900s for their fur
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Species which greatly
influences an ecosystem.
If the species decreases or
eradicates, the ecosystem
changes and its balance
breaks down.
2. Maintaining mechanisms of biodiversity
3) Keystone species
Fluctuations of population
Sea otter
Fish
Sea urchin
Kelp
Prey-predator interaction
Indirect interaction
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2. Maintaining mechanisms of biodiversity
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
3) Keystone species
2. Maintaining mechanisms of biodiversity
3) Keystone species
Photo: Tamiji Inoue
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
2. Maintaining mechanisms of biodiversity
3) Keystone species
Which is the keystone species?
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
Photo: Yasunori Maezawa &
Echigo-Matsunoyama
Museum of Natural Science,
‘Kyororo’
Summary 2. Maintaining mechanisms of biodiversity
 Organisms which are seen inhabiting the same
environment actually differentiate their living space,
time of activity, food, and so on.
 In mutualistic and parasitic relationships, fixation of
species-specific partnerships enables many species to
survive.
 Keystone species is an especially important species
for maintaining an ecosystem.
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
Summary of Today’s Topics
Why have the earth’s organisms become so diverse?
1. Biodiversity has evolved through long-time association
between organisms and environment, and interspecific
interaction.
2. The present biodiversity is maintained by segregation of
niche and fixation of interspecific interaction.
3. We often recognize the whole web of an ecosystem by the
loss of keystone species. However, there are many
ecosystems whose keystone species has not been
identified yet.
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
Exercises
Let’s do the exercises below:
1. Among the following three phenomena, mention all examples which
you consider to be the process of evolution. In those which you do
not choose, explain the reason why you think so.
a) A cabbageworm grows into a pupa, then becomes a butterfly.
b) A mule is produced by crossing a male donkey and a female horse.
c) A plague of harmful insects occurs in paddies. Pesticide which had
effectively controlled the insects until last year is not effective
against the plague.
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
Exercises
Let’s do the exercises below:
2. Mention an example of mutualism and explain each
profit which is brought by the partner. Then think about
how the mutualism has evolved.
3. Biological evolution is proceeding now. What kind of
species may appear in the future, evolved from the
present species?
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
Column 1: Cospeciation and host-shift
Parasitism sometimes brings a number of new species.
-parasitism between stag beetles and mites-
Parasitic mite
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Photo: National Institute for Environmental Studies, Koichi Goka
Column 1: Cospeciation and host-shift
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
Data & Design: Koichi Goka
Column 2: Keystone species
General flowering period in tropical rainforest in Southeast Asia
Fig sp.
Fig sp.
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Column 2: Keystone species
No general flowering period in tropical rainforest in Southeast Asia
Fig sp.
Fig sp.
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
Glossary (1/3)
Arm’s race
Phenomena in which prey and predator species develop their attack strategy and
defense strategy, respectively, and evolve together.
Coevolution
Phenomena in which several species have influenced each other’s survival and
reproduction in the process of evolution.
Cospeciation
In the process of evolution, several species have influenced each other’s survival
and reproduction, then synchronously produce new species.
General flowering
Flowering phenomena which are observed in tropical rainforests in Southeast Asia.
Many canopy tree species synchronously flower at intervals of several years.
Triggers of flowering are thought to be severe drought or low temperature.
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
Glossary (2/3)
Interspecific interaction
Several kinds of interactions in which organisms influence on each other, such as
competition, predation, mutualism, and so on.
Isolation
Preventing gene exchange among populations by geographical barriers.
Molecular phylogeny
Phylogeny is a tree diagram which expresses interspecific relationships and
evolutionary history. In molecular phylogeny, the degree of similarity of base
sequences is a measure of interspecific affinity.
Mutualism
A kind of interspecific interaction in which all organisms within the interaction
increase their fitness.
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
Glossary (3/3)
Pollinative mutualism
Mutualism between angiosperms and pollinators (insects, birds, mammals, etc).
Angiosperms have the profit of carrying pollens to conspecifics, and pollinators
have the profit of getting food (nectar and pollens).
Species-specific relationship
Relationships in which specified species are closely tied in with each other, and
do not accept other species.
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
References
Itino T., Davies S.J., Tada H., Hieda Y., Inoguchi M., Itioka T., Yamane S. and Inoue T.
(2001)
Cospeciation of ants and plants. Ecological Research 16:787-793
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.
Authors & Credits
The Futurability of Biodiversity Chapter 2
Why have the earth’s organisms become so diverse?
Authors
Aya Hatada
Takao Itioka
Masahiro Ichikawa
Stewart Wachs
Martin Piddington
Applications
CutPRO3 Real tough. Animal and Insect version (Design Office Kyowa)
Microsoft PowerPoint®
Sugoneta illustration package. Animal encyclopedia (Grapac Japan)
Illustration & design
Be4°TECH
Koubou Yecoruka
Photos
Aya Hatada
Biodiversity Photos
Chihiro Handa
Daisuke Fukuda
Echigo-Matsunoyama Science of Natural Museum, ‘Kyororo’
Hiroshi Tanaka
Koichi Goka
National Institute for Environmental Studies
Takao Itioka
Shoko Sakai
Tamiji Inoue
Takashi Matsumoto
Yasunori Maezono
Data provider
Koichi Goka
Copyright 2010 Research Institute for Humanity and Nature. All Rights Reserved.