Post on 05-Jun-2020
• There are different interspecific
interactions, relationships between
the species of a community (what’s
the definition of a community
again?).
• While you’re at it, what’s the
definition of “interspecific”?
Introduction
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Here’s some inTRAspecific stuff before we
get back to the inTERspecific stuff
https://www.facebook.com/ScienceNOW/v
ideos/10154345906945108/
1:45. ties together a few things, like Gene
editing with CRISPR
• Possible interspecific interactions are introduced in
Table 53.1, and are symbolized by the positive or
negative affect of the interaction on the individual
populations.
1. Populations may be linked by
competition, predation, mutualism and
commensalism.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Competition.
• Interspecific competition for resources can
occur when resources are in short supply.
• There is potential for competition between
any two species that need the same limited
resource.
• The competitive exclusion principle: two
species with similar needs for the same limiting
resources cannot coexist in the same place.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• The ecological niche is the sum total of an
organism’s use of abiotic/biotic resources in the
environment.
• The competitive exclusion principle can be
restated to say that two species cannot coexist
in a community if their niches are identical.
• This is the “this town’s not big enough for the
both of us” principle.
• What are some possible outcomes of this
competition?
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Classic experiments confirm this principle.
Fig. 53.2
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Resource partitioning is the differentiation of
niches that enables two similar species to
coexist in a community. Watch here new stuff!
Fig. 53.2Fig. 53.3
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Character displacement is the tendency for
characteristics to be more divergent in sympatric
populations of two
species than in
allopatric
populations of the
same two species.
• Hereditary changes
evolve that bring
about resource
partitioning.
Fig. 53.4
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
2.D.1.b. Explain how an organism activities
are affected by interactions with biotic and
abiotic factors by describing the activities
below:
1.Symbiosis (mutualism, commensalism,
parasitism)
2.Predator–prey relationships
3.Water and nutrient availability,
temperature, salinity, pH
• Predation. All these fit into the predator category.
• A predator eats prey.
• Herbivory, in which animals eat plants.
• In parasitism, predators live on/in a host and
depend on the host for nutrition.
• Predator adaptations: many important feeding
adaptations of predators are both obvious and
familiar.
• Claws, teeth, fangs, poison, heat-sensing
organs, speed, and agility.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
3.E.1.a. Organisms exchange information
with each other in response to internal
changes and external cues, which can
change behavior. Explain how each situation
below relates to this statement.
1.Fight or flight response
2.Predator warnings
3.Protection of young
4.Plant-plant interactions due to herbivory
5.Avoidance responses
3.E.1.a. Organisms exchange information
with each other in response to internal
changes and external cues, which can
change behavior. Explain how each situation
below relates to this statement.
1.Fight or flight response
2.Predator warnings
3.Protection of young
4.Plant-plant interactions due to herbivory
5.Avoidance responses
• Plant defenses against herbivores include chemical
compounds that are toxic. IN AP SYLLABUS
• And look at this connection with communication TED talk
17 min . Or do a Wood Wide Web make-a-graph?
• Behavioral defenses include fleeing, hiding, self-defense,
noises, and mobbing, flocks, herds, etc.
• Camouflage includes cryptic coloration, deceptive
markings.
Fig. 53.5Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Justify scientific claims, using
evidence, to describe how timing
and coordination of behavioral
events in organisms are regulated
by several mechanisms.
Create a representation that describes
how organisms exchange information in
response to internal changes and
external cues, and which can result in
changes in behavior. Bird songs.
• Mechanical defenses include spines.
• Chemical defenses include odors and toxins
• Aposematic coloration is indicated by
warning colors, and is sometimes associated
with other defenses (toxins). Group gains by
possible sacrifice of individuals.
Fig. 53.6
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Mimicry is when organisms resemble other
species.
• Batesian mimicry is where a harmless
species mimics a harmful one.
Fig. 53.7
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Müllerian mimicry is where two or more
unpalatable species resemble each other, like
this bee and its wasp mimic.
• Even plants can mimic.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 53.8
• Mutualism is where
two species benefit from
their interaction.
• Commensalism is
where one species
benefits from the
interaction, but other
is not affected.
• An example would
be barnacles that
attach to a whale.
• How about this one?Fig. 53.9
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Here’s a really neat look at termites!
• https://www.youtube.com/watch?v=e02keFYEW
eU
• 7 minutes. Well worth it!!
• And a shorter, 1 min., example in puffer fish
Amensalism: is an interaction in which one organism is harmed, while
the other is neither affected nor benefited. An example is when one species
exudes a chemical compound as part of its normal metabolism that is
detrimental to another organism. The bread mold penicillium is a common
example; penicillium secrete penicillin, a chemical that kills bacteria. A
second example is alleopathy such as when black walnut tree (Juglans nigra),
secretes a chemical that harms or kills some species of neighboring plants.
• Coevolution and interspecific interactions.
• Coevolution refers to reciprocal evolutionary
adaptations of two interacting species.
• When one species evolves, it exerts selective
pressure on the other to evolve to continue the
interaction.
• For example, adaptations for speed in both
cheetahs and antelopes.
• Flowers and their pollinators are classic
examples.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• The trophic structure of a community is determined
by the feeding relationships between organisms.
• The transfer of food energy from its source in
photosynthetic organisms through herbivores and
carnivores is called the food chain.
• These concepts were first revealed by the work of
Charles Elton, the “father” of Ecology.
2. Trophic structure is a key factor in
community dynamics
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Charles Elton first
pointed out that the
length of a food
chain is usually four
or five links, called
trophic levels.
• He also recognized
that food chains are
not isolated units but
are hooked together
into food webs.
Fig. 53.10
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
2.D.1.c. Using one of the examples below, explain
how the stability of populations, communities and
ecosystems is affected by interactions with biotic
and abiotic factors.
1.Water and nutrient availability
2.Availability of nesting materials and sites
3.Food chains and food webs
4.Species diversity
5.Population density
6.Algal blooms
• Food webs.
• Which one(s) are the
producers?
• Which one(s) are
ONLY primary
consumers?
• What transforms
food chains into
food webs?
• A given species may
weave into the web at
more than one trophic
level.Fig. 53.11
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
4.C.4.a.Explain why natural and artificial
ecosystems with fewer component parts
and with little diversity among the parts
are often less resilient to changes in the
environment.
4.C.4.b.Describe why keystone species,
producers, and essential abiotic and
biotic factors contribute to maintaining
the diversity of an ecosystem.
• Dominant species are those in a community that
have the highest abundance or highest biomass (the
sum weight of all individuals in a population).
• If we remove a dominant species from a
community, it can change the entire community
structure from the bottom up.
• These are often producers.
3. Dominant species and keystone species
exert strong controls on community
structure. Bottom up, Top down regulation
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
4.B.3.c.Using the following examples,
explain how species-specific and
environmental catastrophes, geological
events, the sudden influx/ depletion of
abiotic resources or increased human
activities affect species distribution and
abundance.
1.Loss of keystone species
2.Kudzu
3.Dutch elm disease
• Keystone species
exert an important
regulating effect
on other species
in a community. Top
down.
Fig. 53.14
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
The Pisaster experiments done by Robert
Paine in Washington and elsewhere
• Demonstrated that some species that were not
dominant in terms of biomass or numbers exert a
high amount of control on the community they are
a part of. Often at the top of the food chain, can
you see how these keystone species are part of a
feedback system much like we have seen with
blood sugar and lactose and other chemicals, just
on a larger scale? Here’s his story. 20 min.
• Regulatory systems evolve naturally to result in
the homeostatic balances you see in nature.
• If they are removed, community structure is greatly
affected. See this classic story of wolves in Yellowstone.
Fig. 53.15
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• Ecological succession is the transition in species
composition over ecological time.
• Primary succession begins in a lifeless area where
soil has not yet formed.
3. Ecological succession is the sequence of
community changes after a disturbance
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Mosses and lichens colonize first and cause the
development of soil. Pioneer communities.
• An example would be after a glacier has retreated.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 53.19
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Secondary succession occurs where an existing
community has been cleared by some event, but the
soil is left intact. Like after a fire.
• Grasses grow first, then trees and other
organisms. Climax communities.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings