Transcript Biotic and Abiotic Influences on Ecosystems

Biotic and Abiotic Influences on
Ecosystems
(textbook section 2.7)
Today’s Goals
1. Understand how abiotic factors affect
ecosystems
2. Be able to describe some interactions
between organisms
3. Describe how humans can affect these
interactions
Limiting Factor
Any factor that
restricts the size of a
population or where
it can live
e.g. food availability,
disease, predation
Tolerance Range
The range of abiotic
conditions within
which a species can
live
e.g. temperature,
light, moisture
Carrying Capacity
• As a population grows, it requires more food,
water and space. At some point, the
population reaches a maximum number of
organisms that can survive. This limit is called
the carrying capacity.
Carrying Capacity
The maximum
population size of a
particular species that
a given ecosystem can
sustain
e.g. temperature,
light, moisture
What are some ABIOTIC factors in
Ecosystems? How do humans affect
those factors?
Key Abiotic
Factor
Human action and result
Fire and tree cutting can remove shade and expose organisms
to more light
What are some ABIOTIC factors in
Ecosystems? How do humans affect
those factors?
Key Abiotic
Factor
Light
Human action and result
Fire and tree cutting can remove shade and expose organisms
to more light
What are some ABIOTIC factors in
Ecosystems? How do humans affect
those factors?
Key Abiotic
Factor
Light
Human action and result
Fire and tree cutting can remove shade and expose organisms
to more light
Damming rivers and draining wetlands reduces water
availability
What are some ABIOTIC factors in
Ecosystems? How do humans affect
those factors?
Key Abiotic
Factor
Light
Water
Human action and result
Fire and tree cutting can remove shade and expose organisms
to more light
Damming rivers and draining wetlands reduces water
availability
What are some ABIOTIC factors in
Ecosystems? How do humans affect
those factors?
Key Abiotic
Factor
Light
Water
Human action and result
Fire and tree cutting can remove shade and expose organisms
to more light
Damming rivers and draining wetlands reduces water
availability
Farming practices can change nutrient levels in soil
What are some ABIOTIC factors in
Ecosystems? How do humans affect
those factors?
Key Abiotic
Factor
Light
Water
Nutrients
Human action and result
Fire and tree cutting can remove shade and expose organisms
to more light
Damming rivers and draining wetlands reduces water
availability
Farming practices can change nutrient levels in soil
What are some ABIOTIC factors in
Ecosystems? How do humans affect
those factors?
Key Abiotic
Factor
Light
Water
Nutrients
Human action and result
Fire and tree cutting can remove shade and expose organisms
to more light
Damming rivers and draining wetlands reduces water
availability
Farming practices can change nutrient levels in soil
Global warming can reduce available habitat for cool-adapted
species.
What are some ABIOTIC factors in
Ecosystems? How do humans affect
those factors?
Key Abiotic
Factor
Light
Water
Nutrients
Temperature
Human action and result
Fire and tree cutting can remove shade and expose organisms
to more light
Damming rivers and draining wetlands reduces water
availability
Farming practices can change nutrient levels in soil
Global warming can reduce available habitat for cool-adapted
species.
What are some ABIOTIC factors in
Ecosystems? How do humans affect
those factors?
Think-pair-share
Try filling out the ‘Aquatic
Ecosystems’ chart on your own,
then compare with a partner.
What are some ABIOTIC factors in Ecosystems?
How do humans affect those factors?
Key Abiotic
Factor
Light
Human action and result
Activities that increase erosion or stir up bottom sediments
that can reduce light at lower depths
Fertilizer runoff can increase nutrients in the water and
cause algal blooms.
Pollution from burning fossil fuels increases acid rain in
aquatic ecosystems
Industries release heated wastewater in to lakes and rivers,
killing fish and other organisms.
Salting highways and irrigation can increase the
concentration of salt.
What are some ABIOTIC factors in Ecosystems?
How do humans affect those factors?
Key Abiotic
Factor
Light
Nutrients
Human action and result
Activities that increase erosion or stir up bottom sediments
that can reduce light at lower depths
Fertilizer runoff can increase nutrients in the water and
cause algal blooms.
What are some ABIOTIC factors in Ecosystems?
How do humans affect those factors?
Key Abiotic
Factor
Light
Nutrients
Acidity
Human action and result
Activities that increase erosion or stir up bottom sediments
that can reduce light at lower depths
Fertilizer runoff can increase nutrients in the water and
cause algal blooms.
Pollution from burning fossil fuels increases acid rain in
aquatic ecosystems
Industries release heated wastewater in to lakes and rivers,
killing fish and other organisms.
Salting highways and irrigation can increase the
concentration of salt.
What are some ABIOTIC factors in Ecosystems?
How do humans affect those factors?
Key Abiotic
Factor
Light
Nutrients
Acidity
Temperature
Human action and result
Activities that increase erosion or stir up bottom sediments
that can reduce light at lower depths
Fertilizer runoff can increase nutrients in the water and
cause algal blooms.
Pollution from burning fossil fuels increases acid rain in
aquatic ecosystems
Industries release heated wastewater in to lakes and rivers,
killing fish and other organisms.
Salting highways and irrigation can increase the
concentration of salt.
What are some ABIOTIC factors in Ecosystems?
How do humans affect those factors?
Key Abiotic
Factor
Light
Nutrients
Acidity
Temperature
Salinity
Human action and result
Activities that increase erosion or stir up bottom sediments
that can reduce light at lower depths
Fertilizer runoff can increase nutrients in the water and
cause algal blooms.
Pollution from burning fossil fuels increases acid rain in
aquatic ecosystems
Industries release heated wastewater in to lakes and rivers,
killing fish and other organisms.
Salting highways and irrigation can increase the
concentration of salt.
What are some ways that BIOTIC
factors interact in Ecosystems?
1. Competition
• Two or more individuals try to get
enough of one resource
• It is a negative relationship because both
organisms are harming each other.
• Example: foxes and coyotes feed on common
prey such as mice and rabbits.
Symbol: -/-
Competition
Examples
• Elephants fight each other so that
the dominant elephant will get to
breed with the female (intraspecific
competition – within a species)
• Barnacles competing for space on
rocks
• Frogs and lizards compete for the
same insects (interspecific competition –
among different species)
• Trees compete for light in the forest
2. Predation
• One predator eats and kills its prey.
• Example: lynx catch, kill, and eat snowshoe
hare.
Symbol: +/-
Predation Examples
• Leopard killing a buschbock
(gazelle)
• Venus fly trap – traps and digests
flies
• Gypsy moths eat leaves
• Baleen whales eat plankton
3. Mutualism
• Mutualism occurs when two individuals
benefit each other
• Example: a bee and a flower, seed dispersal by
animals, cleaner fish
Symbol: +/+
Mutualism Examples
http://en.wikipedia.org/wiki/File:Impala_mutu
alim_with_birds_wide.jpg
• Red-billed oxpecker eats
insects on impala
• Clownfish live among
anemones
• “Devil’s Garden”: ants poison
all the plants except a single
species –fending off
competition and herbivory.
The tree provides hollow
stems for the ants to live in.
4. Commensalism
• Commensalism occurs when one individual
benefits, the other one neither benefits nor is
harmed
• Example: Barnacles live on humpback whales
but feed on other organisms in the water;
birds building nests in trees.
Symbol: +/0
Commensalism Examples
• Orchids and mosses make
their homes on tree trunks
• Cattle egrets forage in fields
with livestock
5. Parasitism
• Parasitism is when one individual lives on or in
a host organism and feeds on it
• Parasites are generally smaller than their hosts
• Example: tapeworms are parasites of lynxes
and wolves.
Symbol: +/-
Parasitism Examples
• Botfly larvae are internal
parasites of small mammals
• Strangler figs are parasites of
trees
• Heartworms are parasites of dogs
• Cowbirds have a form of nest
parasitism
https://en.wikipedia.org/wiki/File:Eastern_Phoebe-nest-Brown-headed-Cowbird-egg.jpg
Summary Table
Type of Interaction
Sign
Effects
Competition
-/-
Both species affected negatively
Predation
+/-
One species benefits, one species dies
Mutualism
+/+
Both species benefit
Commensalism
+/0
One species benefits, one is unaffected
Parasitism
+/-
One species benefits, one species is
disadvantaged
Practice!
Classify each of these species interactions based
on its description:
•flatworms live attached to the gills of
horseshoe crabs obtaining bits of food from the
crabs’ meals. The crabs are unaffected.
Practice!
Classify each of these species interactions based
on its description:
• Lichens found on tree bark consist of algae
and a fungus. The fungus obtains food from
photosynthesis of the algae and the algae has
a place to live.
Practice!
Classify each of these species interactions based
on its description:
• A flea feeds on the blood of a ground squirrel.
Practice!
Classify each of these species interactions based
on its description:
• Both bluebirds and starlings are cavity nesters
(nest in holes in trees, poles, and fence posts).
Neither species is able to dig holes. Both must
rely on holes that already exist.
Practice!
Classify each of these species interactions based
on its description:
•A wood turtle lays its eggs on sand or gravelsand beaches and banks along streams. A
raccoon eats the turtle’s eggs.
Homework:
• p.55 # 1,7,8