Transcript Ecology Notes

Ecology
Chapters 19,21,22
What is Ecology?


study of interactions between organisms and their living
and nonliving environment
collect information on organisms and environment

to discover and explain patterns
What are Ecological Issues?

man has changed environment drastically


Ozone layer- absorbs UV light (protects organisms)




how do we improve it?
Chlorofluorocarbons (CFC’s) chemicals destroying the ozone
ozone depleting over Antarctica
New evidence has shown improvement
Climatic changes


Greenhouse effect- warming of Earth because of insulating
effect of the gases on the atmosphere. (EX. CO2 and H2O
vapor)
caused by burning of fossil fuels (coal, oil, natural gas)
What are the Ecological Levels of
Organization?

Biosphere


Biome


The entire planet- including all life on Earth and all parts of the
Earth’s land, water, and atmosphere
A group of ecosystems that share similar climates and types of
organisms
Ecosystem
 all the organisms and the nonliving environment found in a
particular place
 pond


- amount of dissolved O2 and CO2, pH, amount of nitrogen
and sunlight, temperature, pollutants
ecosystem is a network where all organisms are linked to other
organisms and to the nonliving environment
Interdependence-any disturbance or change in ecosystem can
interfere with interactions and affect whole ecosystem
What are the Ecological Levels of
Organization?

community - all the interacting organisms of an area




pond - fish, turtles, frogs, algae, plants, bacteria, insects
look at how species interact and how interactions affect
community
population - all the members of a species that live in
one place at one time that can interbreed
organism - a single member of a species
What are biotic and abiotic factors?

Biotic factors



living components of environment
all organisms- animals, plants, bacteria, and fungus
Abiotic Factors- nonliving components of environment
(physical and chemical)

temperature, humidity, pH, salinity, oxygen concentration,
amount of sunlight, availability of nitrogen, precipitation,
soil
Niche vs. Habitat

Niche
 way of life or role a species plays in its environment





range of conditions it can tolerate
how it obtains needed resources (scavenger,
herbivore, etc.)
time of reproduction, number of offspring
when it is active
Habitat

where an organism lives - forest, pond, rotting log,
field
What conditions can an organism tolerate?

Tolerance:



organisms ability to survive and reproduce in wide range of
environmental conditions
individual organisms adapted to function in specific range of
conditions
Tolerance Curve:
Responses to changing conditions

acclimation - adjustment of tolerance to abiotic factors


conformers - do not regulate internal conditions



change as external environment changes
internal cond. remain in optimal range only as long as environ. cond.
remain in that range (snake temp.)
regulators - use energy to control some internal cond.


high elevation - more RBC’s
can keep internal cond. within optimal range over wide range of
environmental cond. (our body temp.)
unsuitable conditions (escape)



desert animals go underground or in shade during day - active at
night
dormancy - state of reduced activity in unfavorable cond. (reptiles
and amphibians in winter)
migration - move to more favorable habitat (birds)
What is symbiosis?

relationships between species living in close association
with one another

What are the five primary ways that organisms
depend on each other?

five main classes of symbiotic relationships in nature:





1. mutualism
2. parasitism
3. commensalism
4. predation
5. competition.
Mutalistic Relationships

The sea anemone’s sting has two functions: to capture
prey and to protect the anemone from predators. Even so,
certain fish manage to snack on anemone tentacles.

The clownfish, however, is immune to anemone stings.
When threatened by a predator, clownfish seek shelter by
snuggling deep into an anemone’s tentacles.
Mutalistic Relationship

If an anemone-eating species tries to attack the
anemone, the clownfish dart out and chase away the
predators.

This kind of relationship between species in which both
benefit is known as mutualism.
Parasitic Relationship




Tapeworms live in the intestines of mammals, where
they absorb large amounts of their hosts’ food.
(endoparasites)
Fleas, ticks, lice, and the leech shown, live on the
bodies of mammals and feed on their blood and skin.
(ectoparasites)
These are examples of parasitism, relationships in
which one organism lives inside or on another
organism and harms it.
The parasite obtains all or part of its nutritional needs
from the host organism.

parasites weaken the host but do not kill it
Commensalism


Barnacles often attach themselves to a whale’s skin.
They perform no known service to the whale, nor do
they harm it. Yet the barnacles benefit from the
constant movement of water—that is full of food
particles—past the swimming whale.
This is an example of commensalism, a relationship
in which one organism benefits and the other is
neither helped nor harmed.
Predator- Prey Relationship

organism that captures, kills, and eats another (the
prey)
 Advantages of Predator:
 1) good sense of smell and/or eyesight
 2) web of spiders
 3) heat-sensitive pit of rattlesnakes
 4) sharp teeth (wolves, sharks), talons (hawks,
owls)
 5) tiger’s stripes (camouflage)
 6) speed (cheetah, shark)
 7) climbing ability (to get to a nest)
Predator- Prey Relationship


mimicry - harmless species resembles a poisonous or
distasteful one


Advantage of Prey:
 1) ability to flee quickly
 2) hiding/camouflage
 3) resemble inedible object
 4) bright, warning colors
 5) resembling other organisms
 6) spines, thorns, foul odor
two or more dangerous or distasteful look similar (many bees
and wasps) - all benefit, predator encountering one avoids
similar ones
herbivore-plant



plant defenses - thorns, spines, sticky hairs, tough leave
chem. defense - poisonous, irritating, bad-taste
medical use - morphine, atropine, codeine, taxol, quinine
Competitive Relationship


use of same limited resource by 2 or more species
Competitive exclusion - one species in community
eliminated due to competition for same resource

one uses it more efficiently and has a reproductive advantage
Think????

In 1883, the volcanic island of Krakatau in the Indian
Ocean was blown to pieces by an eruption. The tiny
island that remained was completely barren.

Within two years, grasses were growing. Fourteen
years later, there were 49 plant species, along with
lizards, birds, bats, and insects. By 1929, a forest
containing 300 plant species had grown. Today, the island
is blanketed by mature rain forest.

How did the island ecosystem recover so quickly?
Primary and Secondary Succession

Ecological succession is a series of more-or-less
predictable changes that occur in a community over time.

Ecosystems change over time, especially after
disturbances, as some species die out and new species
move in.

Over the course of succession, the number of different
species present typically increases.
Primary Succession

What can cause Primary Succession?



Volcanic explosions can create new land or sterilize
existing areas.
Retreating glaciers can have the same effect, leaving only
exposed bare rock behind them.
Succession that begins in an area with no remnants
of an older community is called primary
succession.
Example of Primary Succession



For example, in Glacier Bay, Alaska a retreating
glacier exposed barren rock.
Over the course of more than 100 years, a series of
changes has led to the hemlock and spruce forest
currently found in the area.
Changes in this community will continue for centuries.
Primary Succession


The first species to colonize barren areas are called
pioneer species.
One ecological pioneer that grows on bare rock is
lichen—a mutualistic symbiosis
between a fungus and an alga.
Secondary Succession

Causes of Secondary Succession

Wildfire, hurricane, or other natural disturbance.
Can also follow human activities like logging and farming.

Advantage to disasters:



many species are adapted to them.
Although forest fires kill some trees, for example, other trees are
spared, and fire can stimulate their seeds to germinate.
Secondary Succession


Sometimes, existing communities are not completely
destroyed by disturbances called secondary
succession.
Secondary succession proceeds faster than primary
succession, because soil survives the disturbance.
As a result, new and surviving vegetation can regrow
rapidly.
Secondary Succession


Example of secondary succession taking place in
abandoned fields of the Carolinas’ Piedmont.
Over the last century, these fields have passed
through several stages and matured into oak forests.
Changes will continue for years to come.
Climax Community



Stable end point reached after predictable series of
changes
organisms of each stage alter physical environment that
can prevent their survival but encourages organisms of
next succeeding stage
Recent studies, however, have shown that
succession doesn’t always follow the same path, and
that climax communities are not always uniform and
stable.
Answer to Succession Question:

On both Mount Saint Helens and Krakatau, primary
succession proceeded through predictable stages.

The first plants and animals that arrived had seeds,
spores, or adult stages that traveled over long distances.

Hardy pioneer species helped stabilize loose volcanic
debris, enabling later species to take hold.

Historical studies in Krakatau and ongoing studies on
Mount Saint Helens confirm that early stages of primary
succession are slow, and that chance can play a large
role in determining which species colonize at different
times.
Primary Producers (Autotrophs)

Capture energy to make own food

Photosynthesis – using the sun’s energy

Chemosynthesis- use energy from inorganic molecules
Primary Producers (Autotrophs)



Store energy in forms available to other organisms
that eat them, and are therefore essential to the flow
of energy through the biosphere.
For example, plants obtain energy from sunlight and
turn it into nutrients that can be eaten and used for
energy by animals such as a caterpillar.
Who are Primary Producers?


Plants , Algae, some Protists
Photosynthetic bacteria, most commonly cyanobacteria
Think?????

What happens to energy stored in body tissues when one
organism eats another?

Energy moves from the “eaten” to the “eater.” Where it
goes from there depends on who eats whom!
Consumers (Heterotrophs)


Consume organic molecules made by other organisms
Who are consumers?


Animals, most protists, fungi, many bacteria
Types:


herbivore - eat producers
carnivore - eats other consumers



omnivore - eats both producers and consumers
scavenger - feeds on remaining dead organic matter


include snakes, dogs, cats, and a giant river otter.
king vulture, are animals that consume the carcasses of other
animals that have been killed by predators or have died of other
causes.
decomposers - cause decay by breaking down complex


molecules in dead organic matter (recycle nutrients)
bacteria and fungi
How does energy Flow?

trophic level - an organism’s position in the sequence of
energy transfers






energy flows from producers to consumers
food chain - transfer of energy through a single series of
organisms
hawk (tertiary consumer)
4th trophic level
(3rd order consumer)
snake (secondary consumer)
3rd trophic level
(2nd order consumer)
mouse (primary consumer)
2nd trophic level
(1st order consumer)
grass (primary producer)
1st trophic level
How does energy Flow?

food web - series of interrelated food chains (p. 418)



many consumers eat more than one type of food
several species may feed on same organism
Explain happens to the food web if the krill population
decreases?
How productive are Producers?

primary productivity - rate at which producers
capture energy in an ecosystem (Carrying capacity)



some sugar used for respiration, maintenance and repair
some used to make new organic material (growth,
reproduction)
biomass - the living organic material in an ecosystem


only the energy in biomass is available to other organisms
the amount of biomass in a trophic level is determined by
the amount of energy available.
Pyramids

Ecological pyramids

show the relative amount of energy or matter contained within
each trophic level in a food chain or food web.
A small portion of the energy that passes through any
trophic level is ultimately stored in the bodies of organisms
at the next level.
 Organisms expend much of the energy they acquire on
life processes:


such as respiration, movement, growth, and reproduction.
Most of the remaining energy is released into the
environment as heat; a byproduct of these activities.
Energy Pyramid- 10% Rule


On average, about 10 percent of the energy
available within one trophic level is transferred to the
next trophic level.
The more levels that exist between a producer and a
consumer, the smaller the percentage of the original
energy from producers that is available to that
consumer.
Ecosystem Recycling


biogeochemical cycle - substances move from abiotic
environment to biotic and back again
How?



Water Cycle
Carbon Cycle
Nitrogen Cycle
Water Cycle

Evaporation - water molecules evaporate from the ocean or
other bodies of water to form water vapor).

Transpiration- evaporation of water from stomata in plant
leaves
Precipitation- water vapor condenses into tiny
droplets that form clouds.


Those droplets become large enough, fall in the form of
rain, snow, sleet, or hail.
Carbon Cycle




CO2 used in P.S. - plants make carbohydrates from it
respiration releases CO2
decomposers release CO2 when they break down
organic compounds
burning fossil fuels also releases CO2, as does burning of
rain forest
Nitrogen Cycle



All organism need N to make amino acids- to build proteins and
nucleic acids
78% of atmosphere is nitrogen gas (not usable)
nitrogen fixation - converting N2 to ammonia (NH3)





nitrogen-fixing bacteria live in soil and in roots of legumes (beans, peas,
clover, alfalfa)
mutualism (plant provides home and sugar, bacteria supplies nitrogen)
Ammonification - decomposers break down dung, urine, dead
bodies and release nitrogen as NH3
nitrification - soil bacteria oxidize ammonia to nitrites (NO2)
and nitrates (NO3) - plants use nitrates to form amino acids
denitrification - anaerobic bacteria convert nitrates to N2
Nitrogen Cycle