Transcript Matter, Energy, and Life

Biological Communities &
Species Interaction
Who Lives Where and Why?
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Critical Factors and Tolerance Limits
1. nutrients, temperature, water supply, living
space and other physical factors
2. tolerance limits - minimum and maximum
levels (range) for each of the critical factors
3. factors are unique for each species, and often
complex interaction between several factors
Saguaro cacti are extremely
Sensitive to temperature
Desert pupfish, lives in desert,
Can survive at high temp up to
42 C and in high salt.
But eggs and juvenile fish live
between 20-36C and are
killed by high salt
Environmental
Indicators
Jimson Weed a.k.a Loco Weed,
or Devil’s Weed
Grows where selenium and uranium are
high
Datura stramonium
Lichen and Frogs are
Pollution Indicators
Mulefat: native plant, indicates the
presence of water
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Natural Selection, Adaptation, Evolution
1. physiological modifications - traits of species
that allow them to “adapt” to environment
2. evolution by natural selection -over time, traits
that are beneficial “survive” while those that
are less beneficial do not
3. factors influencing evolution - change in
environment; predation; competition; luck
A trait that provides
and advantage is
known as an
ADAPTATION
Selection (Natural or Artificial)
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The Ecological Niche
1. habitat -place and environmental conditions in
which an organism lives
2. ecological niche - functional description of role
of species within a community
 how
it obtains food
 relationships with other species
 role it plays in biotic and abiotic aspects of area
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Predation
1. predator -an organism that feeds directly on
another living organism
 predator
- prey relationships play vital a central role
in evolution of many species
 competitive exclusion principle - two species whose
niche overlap too much will compete for resources
KEYSTONE SPECIE
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Keystone Species
1. keystone species - species or group of species
whose impact on community is greatest
 not
always the highest on the food chain
i.e. Wolves limit the grazing of herbivores
i.e. Sea star limits population of clams etc.
Parasite: A type of symbiosis in which
organism that completes part of its life cycle
on a host organism. The host is harmed and
the predator is not.
 Pathogen: Disease causing organisms that
are not free living.
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Competition
1. intraspecific competition - competition for
resources among members of same species
 territoriality
2. interspecific competion - competition for
resources among members of different species
What two ways do grasses compete?
Why is intraspecific competiton more intense?
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Symbiosis - intimate interaction of species
(often with one relying on another)
1. commensalism- one organism benefits, other is
neither helped nor harmed
i.e. Bird in a tree
2. mutualism -both organisms benefit from a mutual
relationship with each other
i.e. mycorrhizae and lichen
3. parasites- one organism benefits one is harmed
i.e. Sporozoan that causes malaria
Mimicry and Camouflage
1. Batesian mimicry- a
related species evolves
over time to appear
similar to a dangerous
species
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Butterflies
Left is unpalatable
Right is palatable
Batesian Mimicry
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2. Muellerian mimicry - one species evolves
over time to appear similar to unrelated species
Camouflage
Community Properties
Productivity - rate of biomass production
 Abundance and Diversity
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1. abundance - actual total number of individual
organisms in a community
2. diversity - number of actual species or niches
present in a particular ecosystem
What Is…..?
ZooPlankton
 Phytoplankton
 Giant Kelp
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Complexity and Connectedness
1. complexity - number of species at each trophic
level and number of trophic levels
2. connectedness - the relatedness of organisms
within the entire trophic system
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Resilience and Stability
–
–
–
constancy - lack of much change over time
inertia - change occurs, much resistance
renewal - ability to repair after severe damage
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Community Structure
–
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spatial distribution of organisms
relation of organisms to their surroundings
 nesting
birds
 schools of fish
 clusters of trees
Factors influencing distribution
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Dispersal methods
a) availability of water in the desert
Behavior
Biotic factors (predation parasitism, competition,
disease)
b) competition for nesting space in a penguin
colony.
c) clustered (optimum protection bird and fish)
Abiotic factors (availability of nutrients, water,
light or presence of chemicals)
Community in Transition
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Ecological Succession - gradual change of
ecosystem over time
1. primary succesion - community develops on
site with little/no biotic forms
2. secondary succession - new species begin to
replace “original” species on the site
3. climax community - community that finally
develops and resists any further change
4. equlibrium community - undergoes periodic
disruptions and renewal
 forests,
grasslands
5. fire-climax community - often depends upon
fire for part of it normal life cycle
the chaparral
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Introduced Species - new species brought
into a community
1. natural -species moves into a community
without human intervention
2. human introductions - new species brought into
community by humans
 eucalyptus
trees
 Rabbits in Australia
 Mongoose in Jamaica and Hawaii
Mongoose fighting Cobra
Overgrowth of Introduced Rabbits
In Australia