Transcript Evolution

Chapter 5:
Evolution and
Community Ecology
Chapter 5 pages 126- ……..
Section 1: Evolution
Answer the questions and define the terms:
1. Describe the four primary mechanisms
of biological evolution
2. Describe how speciation and extinction
affect the diversity of life on Earth.
TERMS: evolution, gene mutation, genetic
drift, natural selection, fitness, adaptation,
artificial selection, speciation, extinction.
Incredible Diversity of Life
to 1.8 million
known species
► Possibly 13-20 million
► Tropical Rain Forests,
Coral Reefs and
everywhere else
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► 1.5
Evolution
►What
YOU?
makes you,
What
makes
each
species
unique
and
different?
Genes
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of DNA
codes for each
particular trait
►Tall, small, blue
eyes, human,
goldfish, pine tree
►Evolution is a
change of genes
over time
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►Sequences
over
time”
►Change of Gene
Pool over time
►Why would genes
change over
time?
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►“Change
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Evolution
4 Ways Evolution Occurs
►Mutation
►Migration
Drift
►Natural Selection
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►Genetic
Accidental
change in DNA
that can give rise
to variation
among
individuals
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Mutation
Migration: GENE FLOW
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Sometimes called “Gene Flow”
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Movement of
individuals
into
(immigration)
or out of
(emigration)
a population
Gene Flow (Migration)
• Natural Disasters
• Run in with
human nets, etc.
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Evolution that
occurs by chance
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Genetic Drift
Natural Selection
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by which
traits useful for
survival and
reproduction are
passed on more
frequently than
those that are
not
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► Process
3 Conditions for Natural Selection
(1) Organisms produce more offspring
than can survive.
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(3) Individuals vary in fitness, or
reproductive success
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(2) Individuals vary in characteristics,
some of which are heritable.
3 Conditions for Natural Selection
Nature has
limitations
(limiting factors)
•
Struggle for
survival
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(1) Organisms
produce more
offspring than
can survive.
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(2) Individuals vary in
characteristics, some of
which are heritable
► Not every species is
same
► Some fish are faster,
darker, smaller
► Genes different
► Heritable Differences
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3 Conditions for Natural Selection
3 Conditions for Natural Selection
(3) Individuals vary in
fitness, or reproductive
success
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of Fittest
► Fittest for its environment
► Adaptation: an
inherited trait that
increases an organisms
chance of survival and
reproduction.
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► Survival
Adaptations
Desert plants have small or
no leaves at all
The insect
that blends
in and is
able to
survive
may be
more likely
to
reproduce.
Adaptations
Big ears of
desert jack
rabbit allow it to
cool off quickly
White coat of
polar bear
helps in
hunting
Long neck of giraffe
allow it to
reach of
Results
food
natural
selection all
around us
NATURE
SELECTS
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Artificial Selection:
selective breeding
of organisms by
humans
►Selecting certain
desirable traits
►Size, sweetness,
color, shape,
►Very common
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Artificial Selection: How Humans
Use Evolution
Artificial Selection
Selecting desirable traits
and breeding only those
with those traits.
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Resistance: the ability
of one or more
organisms to tolerate
a chemical designed
to kill it
► Able to survive and
reproduce
► Pesticide resistance
► Antibiotic resistance
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Resistance
Impacts of Natural Selection:
Resistance
Why is
this a
problem
?
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Speciation: How did we get
millions of species?
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• Can occur in a number
of different ways; the
most important way is
called allopatric
speciation– Geographic
Isolation
• Has resulted in every
form of life on Earth—
today and in the past
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Speciation
• Process by which new
species are generated
The canyon is a barrier to dispersal by small mammals, and
as a consequence the isolated populations can diverge.
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Sympatric Speciation
Sympatric speciation is the
process through which new
species evolve from a single
ancestral species while
inhabiting the same
geographic region.
Sympatric refers to
organisms whose ranges
overlap or are even identical,
so that they occur together
at least in some places, such
a distribution may be the
result of sympatric
speciation.
The disappearance of species from
Earth
•
Generally occurs gradually, one
species at a time, (BACKGROUND
RATE of EXTINCTION). When
environmental conditions change
more rapidly than the species can
adapt extinction occurs.
•
There are five known mass
extinction events, each of which
wiped out a large proportion of
Earth’s species.
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•
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Extinction
Biodiversity has increased over time, but mass extinctions are
also natural events (5 major events)
How do we get this data?
Did You Know? During the Permo-Triassic extinction 250
million years ago, 70% of all land species and 90% of all
marine species went extinct.
gone forever
► NORMAL
► Mass Extinction: short
period of time when
large number of species
go extinct (65 MYA)
► Currently in mass
extinction…caused by
humans
► Rapid climate change
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► Species
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Extinctions
Invasive Species
The zebra mussel has
completely displaced 20 native
mussel species in Lake St. Clair.
Invasive Species
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Adversely affect the habitats and
bioregions.
• They invade economically,
environmentally, and/or ecologically.
• Invasive species can be either plants or
animals and disrupt by dominating
habitats.
• The problem is they have no natural
controls such as predators or
competition for resources.
•
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Invasive Species
Invasive species damage the lands and
waters that native plants and animals
need to survive.
They hurt economies and threaten human
well-being.
The estimated damage from invasive
species worldwide totals more than $1.4
trillion – five percent of the global
economy
Section 1: Evolution Review
► Describe
the four primary mechanisms of
biological evolution
► Describe how speciation and extinction
affect the diversity of life on Earth.
► TERMS: evolution, gene mutation, genetic
drift, natural selection, fitness, adaptation,
artificial selection, speciation, extinction
Section 1 Quiz
Which of the following best describes a successful
individual in evolutionary terms?
A.
A successful individual possesses traits that are
different from the traits of the rest of the population.
B.
A successful individual produces many offspring that
possess unique traits.
C.
A successful individual is well adapted to its
environment and produces offspring that survive to pass on
genes.
D.
A successful individual will be well adapted to its
environment and produce a few high quality offspring.
1)
C.
A successful individual is well adapted to its
environment and produces offspring that survive to
pass on genes.
2) In the history of the world, how many
mass extinctions have occurred?
A. 5
B. 7
C. 10
A.
5
D. 13
3) In a mass extinction, the rate of
extinction exceeds
A. 99 percent.
B. 85 percent.
C. the rate of environmental change.
D. the rate of background extinction.
D. the rate of background extinction
4) A reintroduced population of wolves in a
national park is 90% grey and 10% black,
consistent with the wolf population in other
regions. After several generations in isolation,
the national park’s wolf population is 60%
grey and 40% black. The wolf population has
likely experienced
A. natural selection. B. genetic drift
Evolution that occurs
B. genetic drift.
by chance
C. mutations.
D. migration.
5) When the environment changes too
quickly for an organism to adapt, what
will occur?
A) Evolution
B) Speciation
C) Genetic Drift
D) Extinction
D. Extinction
True or False
6) Two populations of a deer species
are separated when a glacier forms.
After the glacier melts, the two
populations have become different
species. This is an example of allopatric
speciation.
TRUE
Short Answer
7) A disaster wipes out 50 percent of a small
population of birds. Prior to the disaster,
about half the birds had a green wing patch
and half had a blue wing patch. Several
generations after the disaster, only 10% have
a blue wing patch, and 90% have a green
wing patch. What do you infer happened, and
why?
The bird population experienced genetic drift as the
result of a sudden catastrophe. The disaster
reduced genetic diversity in the population and
changed the proportion of birds with a green wing
patch vs. a blue wing patch.
Short Answer
8) Pronghorn are a species of extremely fast
hooved mammal that live on the plains of
western North America. They are so fast that no
current North American predator can catch
them. During the ice age, cheetahs occupied
North America. Speculate about how pronghorn
became so fast.
Pronghorn probably evolved in an evolutionary “arms
race” with the cheetah population. They became
faster and faster to escape from cheetahs, which were
probably fast enough to catch them.
Section 2: Species Interaction
► Discuss
the factors that influence an
organisms niche
► Compare and contrast predation, parasitism,
herbivory
► Describe mutualism and commensalism
► TERMS: niche, tolerance, resource
partitioning, predation, coevolution,
parasitism, symbiosis, herbivory, mutualism,
commensalism.
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Species Interaction
What resources
are the plants in
this picture
competing for?
Competition for
resources all
around us
an
organism’s use of
resources and
functional role in a
community
► Habitat
► Food It Eats
► When, How
Reproduces
► What organisms does
it interact with
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► Describes
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Niche: Organisms JOB in life
Affected by an
organism’s
tolerance—its ability
to survive and
reproduce under
changing
environmental
conditions
•
Often restricted by
competition
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•
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Niche Impacted By Tolerance and
Competition
Tolerance Limits
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 A species with a restricted tolerance for
environmental conditions is a specialist
• A species with a Wide tolerance is called a
generalist
Fundamental vs. Realized Niche
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Realized = With
competition
(restricted niche)
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Fundamental =
Without
competition
►Organisms
Competition
compete when
they seek the same limited
resource.
►In
rare cases, one species
can entirely exclude another
from using resources.
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reduce competition,
species often partition
resources, which can lead to
character displacement.
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►To
Resource Partitioning
► The
zebra mussel has completely displaced
20 native mussel species in Lake St. Clair.
Predation (+/-)
► The
process by which a predator hunts,
kills, and consumes prey
cycles in predatory and prey
population sizes
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► Causes
Predation
traits
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such as
camouflage,
mimicry, and
warning
coloration have
evolved in
response to
predator-prey
interactions.
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► Defensive
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Predation and Co-evolution
Rough-Skinned Newt
Did You Know? A single rough-
skinned newt contains enough poison
to kill 100 people. Unfortunately for
the newt, its predator, the common
garter snake, has coevolved resistance
to the toxin.
► Some
predator-prey
relationships are
examples of
coevolution, the
process by which
two species evolve
in response to
changes in each
other.
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The Madagascar star orchid
produces nectar at the
bottom part of its slim, footlong throat.
After observing a specimen,
Charles Darwin predicted the
existence of a moth with a
proboscis long enough to
reach that nectar.
Sure enough, decades later
the giant hawk moth of
Madagascar was discovered.
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Example of Co-evolution
Parasitism: One
organism (the
parasite) relies on
another (the host) for
nourishment or for
some other benefit
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Herbivory: An animal
feeding on a plant
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Parasitism and Herbivory
(+/–)
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Parasitism and Herbivory
(+/–)
Malaria is a
disease caused by
a parasite called
Plasmodium that is
spread to humans
by the bite of an
infected Anopheles
mosquito.
Parasitism and Herbivory
(+/–)
Mutualism: a
relationship in which
two or more species
benefit
•
Commensalism: a
relationship in which
one species benefits
while the other is
unaffected
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Mutualism (+/+) and
Commensalism (+/0)
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Clown Fish and Sea
Anemones demonstrate
mutualism because
Anemones provide the
Clown Fish with protection
from predators while
Clown fish defend the
Anemones from Butterfly
fish who like to eat
Anemones.
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EXAMPLE of Mutualism (+/+)
Example of Commensalism (+/0)
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Desert trees (Polo verde) and shrubs
provide shade and leaf litter to the soil
beneath the tree which allows the soil
underneath to hold moisture. The
area underneath the tree remains
cooler and more moist than the
surrounding desert area making it
easier for other desert plants to
germinate and grow
Section 2 Review Species
Interaction
► Discuss
the factors that influence an
organisms niche
► Compare and contrast predation, parasitism,
herbivory
► Describe mutualism and commensalism
► TERMS: niche, tolerance, resource
partitioning, predation, coevolution,
parasitism, herbivory, mutualism,
commensalism.
Section 2 Quiz
1) Madagascar, several species of lemur eat
bamboo, but each species specializes in one part
of the bamboo—one species eats mature
bamboo stalks, one species eats bamboo shoots,
and one species eats leaves. This is an example
of
► A. speciation.
► B. resource partitioning.
B. Resource
► C. competition.
Partitioning
► D. niche partitioning.
2) In the example above, one lemur species eats
only bamboo shoots. Bamboo shoots contain a high
level of cyanide, a toxic chemical. This lemur species
has developed a tolerance for a certain amount of
cyanide. What do you think will happen over time?
A.
The level of cyanide in the bamboo population
will increase.
B.
The level of cyanide in the bamboo population
will decrease.
C.
The level of cyanide in the bamboo population
will remain the same.
D.
The level of cyanide in the lemur population
will decrease.
A.
The level of cyanide in the bamboo population will
increase.
3) Two species of finch live in the same
environment. Over time, one develops a
larger beak to consume larger seeds,
while the other develops a narrow beak
to consume more delicate seeds. This is
an example of
A. resource partitioning.
B. character displacement.
C. coevolution.
D. competitive exclusion.
C.
coevolution.
4) An interaction in which an individual
of one species kills and consumes an
individual of another is called
A. predation.
B. parasitism.
C. herbivory.
D. symbiosis.
A.
predation
5) In the western United States, at the
southern edge of their range, moose are
sometimes so severely infested with ticks
that they die. The tick/moose
relationship is best described as
A. predatory.
B. parasitic.
C. symbiotic.
D. mutualistic.
B.
parasitic.
6) A beehive depends on pollen from
flowers to survive. Flowers depend on bees
to pollinate them. The relationship among
these two sets of organisms is
A. parasitic.
B. commensalist.
C. herbivory
D. mutualistic.
D. mutualistic.
7) A niche restricted by competition is a
A. fundamental niche.
B. realized niche.
C. resource partitioned niche.
D. displaced niche.
B.
realized niche
8) A deer browsing on a shrub is an
example of
A. predation.
B. parasitism.
C. herbivory.
D. photosynthesis.
C.
herbivory.
True or False
You have many species of
bacteria living in your gut that
help you with digestion. This
relationship is best defined as
commensalism.
False: Mutualism
Short Answer
9) Explain the difference between
mutualism and commensalisms, with
examples.
In mutualism and commensalism, both species are
unharmed. In mutualism, both species benefit, as in
the example of the hawk moth pollinating the
flower; the flower is pollinated and the moth is fed.
In commensalism, one species benefits while the
other doesn’t experience a negative or a positive
effect. Trees providing shade and moisture to
desert shrubs is an example of commensalism.
NOW you can answer these 2 questions
you wrote down at the beginning of this
chapter.
Explain why a food web is a better representation of
energy flow in a community than a food chain.
Explain how a sudden change in the environment either
through a disaster or through shifts in conditions might
affect the evolution of species in the area.
Compare and contrast what is likely to happen to an area that has
just experienced a forest fire to what has happened to an area
exposed to glaciations over centuries of time. Which will regrow
more quickly and WHY?