Transcript Community Interactions

Community Interactions
QUICK REVIEW
•What is community?
•What is population?
Community Interactions
• Powerfully affect an ecosystem
• Include:
– Competition
– Predation
– Symbiosis
Competition
• When organisms of the same or different
species attempt to use an ecological
resource at the same place and the same
time
– Resource any necessity to life
– Plants and animals compete
– Winner and losers
• Interspecific competition
– Competition between same two species
– When 2 or more species rely on same limited
resource in a community
– Ex. African savannah
Rules, rules, rules
• Fundamental rule in ecology
– Competitive Exclusion Principle
• Russian biologist G.F. Gause
– Paramecium caudatum vs. Paramecium aurelia
• 2 species so similar in requirements that the same
resource limits both population’s growth, and one
species may succeed over another
• No two species can occupy the same niche in the
same habitat and the same time
• Prevents competition
Niche
• Each species unique living arrangement in
a community
• “Role”
• Ex. Lizards in a rainforest
• Includes:
– Habitat
– Food sources
– Time of day organism is most active
Predation
• Interaction where an organism captures
and feeds on another organism
• Predator
– Organism that does the killing and eating
• Prey
– Organism that is being killed and eaten
(victim)
Predator Adaptations
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Speed
Agility
Coloring/camouflage to ambush prey
Packs/teams
– Ex. Wolves
• Acute senses
– Ex. Rattle snake heat sensor organs
• Claws, teeth, fangs, stingers, poison
Prey adaptations
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Safe locations
Flee
Coloring/camouflage to hide
Defensive coloration
– “warning coloration”
• Mimicry
– Organisms imitate dangerous organisms by
appearance and actions
• Hawk moth larva
• Plants
– Thorns, spines, poisonous chemicals
Symbiosis
• Any relationship where
two species live closely
together
• Symbiosis literally
means “living together”
• 3 main types
– Parasitism
– Mutualism
– commensalism
What type of relationship is this?
• Who is helping who?
Mutualism
• Both species benefit
from the relationship
• A Happy couple
• Flowers and bees
– Flowers need bees for
pollination, bees need
flowers nectar
What type of relation ship is going
on here?
• Who is helping who?
Commensalism
• One member of the relationship benefits
while the other is neither harmed nor
helped
• One-sided
• Food or shelter
• Barnacles on whale
Ants and aphids
What type of interaction is going on
here?
Parasitism
• One organism lives on or inside another
organism and harms it
• Parasite obtains all or part of its nutrients from
the other organism
• Host
– Organism that is harmed in relation ship; the one that
provides the nutrients to the parasite
• Parasite
– Organism that gets its nutrients from the host
• Do they want to kill their host?
– No, because they need them…they will weaken or
hurt the host in some way
Recap
• What are the three types of interactions in
a community?
– Competition
– Predation
– Symbiosis
• What types do we have?
– Mutualism
– Commensalism
– Parasitism
Ecological Succession
• Do all ecosystems stay the same all the
time?
• What are some things that cause changes
to ecosystems?
– Natural and unnatural
– Quickly and slowly
• Ecosystems are constantly changing in
response to human and natural
disturbances.
• As an ecosystem changes, older habitants
die out and new organisms move in,
causing more change
Ecological Succession
• Series of predictable changes that occur in
a community over time
– Physical environment
– Natural disturbance
– Human disturbance
Primary Succession
• Succession on land
that occurs on
surfaces where no
soil exists
• Volcanic eruptions
• Glaciers melting
Stages of Primary Succession
• Start with no soil, just ash and rock
• First species to populate this area
– “pioneer species”
– For example, pioneer species on volcanic
rock are lichens (LY-kunz)
• Lichens made up of fungus and algae that can
grow on bare rock
• When lichens die, they for organic material that
becomes soil…now plants can grow
Secondary Succession
• Succession following a disturbance that
destroys a community without destroying
the soil
• Natural
– hurricane
– fires
• Human disturbances
– Farming
– Forest clearing
Succession in Marine Ecosystems
• Deep and dark
• Can succession happen?
• 1987 dead whale off of California
– Unique community of organisms living in
remains
– Represents stage in succession in an
otherwise stable, deep-sea ecosystem
– Whale-fall community
Whale-Fall Succession
• Begins when large whale dies
– Sinks to barren ocean floor
– Scavengers and decomposers flock to carcass , our first community
• Amphipods
• Hagfish
• sharks
• After a year, most tissues have been eaten
– Now, second small community of organisms live here
– Body is decomposing, releasing nutrients into the water
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Small fishes
Crabs
Snails
worms
• Only skeleton remains…
– Third community moves in
• Heterotrophic bacteria
• Decompose oil in bones release of chemical compounds
• Who uses these chemical compounds?
– Chemoosynthetic autotrophs
• In come the crabs, clams, and worms that feed on this bacteria
Human Activity and Species
Diversity
• Land clearing
– Farmland
– Diverse forest replaced with single crop
– Decreases species diversity
• Introduced species
– Humans move a species from its native land
to a new location, intentionally or accidentally
Study
Chapter 35,
Population
Ecology and
Community
Interactions
Teacher,