Transcript Ecology

Ecology
Introduction
What is it?
The study of living things and how
they interact with nonliving things.
Each organism depends in some way
on other living or nonliving things.
Levels of organization
• Biosphere: Broadest level of organization
including all things found on Earth and in
it’s atmosphere.
• Ecosystems: Includes all the organisms and
the nonliving environment found in a
particular place.
• Community: Only includes living parts of
the ecosystem.
Levels of organization
• Population: Includes all the members of a
species that live in one place at one time.
• Organism: Simplest level of organization
that consist of only on living thing.
Example: Biosphere
• Think of it this way: If the earth
were an apple the biosphere
would be only as thick as the
skin on the apple.
• Living things are not distributed
evenly throughout the biosphere.
Example: Ecosystem
• A pond is an ecosystem that contains a
variety of living things: fish, turtles,
aquatic plants, algae, insects, and
bacteria.
Also don’t forget the nonliving:
chemical and physical composition
(water, sunlight)
• They all interact in ways that affect
their survival.
Example: Community
• All the living organisms in the
pond: fish, turtles, pants,
algae, and bacteria.
• Can contain thousands of
species
Example: Population
• All the members of a species that
live together at one time. Like a
species of frogs living in the same
pond and interacting.
Example: Organism
• One single organism like a duck.
Biotic and Abiotic Factors
• Biotic: all the living things in environment:
animals, plants, bacteria, etc.
• Abiotic: all of the non-living things in
environment: pH, salinity, temp, minerals,
amount of sunlight, and precipitation.
Biotic and Abiotic interactions
Abiotic and Biotic factors are not
independent.
Ex: Plants (biotic) need nitrogen (abiotic)
The Niche
• A species’ niche is its way of life, or role
the species plays in its environment.
• A species niche includes a range of things:
– Methods of how it obtains food
– Number of offspring
– Time of reproduction
– All other interactions with its environment
Niche Differences
• A species niche can change in a single
generation.
• Some species survive better than others.
Specialist: have narrow
niches
• Ex. Koala who feeds
only on a few species of
eucalyptus leaves.
Generalist: tolerate a
broad range of things
• Ex. Virginia Opossum
lives all over the U.S.
and eats almost
anything
Questions – Chapter 19
• 1. Describe 3 abiotic factors that can
affect an organism.
• 2. How are biotic and abiotic factors
interdependent?
• 3. How is an organism’s niche different
from its habitat.
• 4. Completely describe the niche of a
squirrel.
• 5. Define and compare dormancy and
migration.
Questions – Chapter 19
• 6. Name 5 different populations.
• 7. What is the difference in immigration
and emigration?
• 8. What is exponential growth?
• 9. What is the shape of an exponential
growth curve?
• 10. How many people lived on Earth
10,000 years ago? How many live on
Earth today (1999)?
• 11. Why has human growth rate
increased so dramatically?
Species Interactions
Several types:
1. Predation – predator captures, kills,
and consumes prey
Important role in natural selection
Avoiding
predators - cont
• a. Camouflage hiding
Avoiding predators - cont
b. Advertising poison –
caterpillars eat
poisonous plant
Avoiding predators - cont
c. Mimicry – harmless
species resembles a
dangerous or
distasteful one.
Harmless viceroy (bottom)
looks like poisonous
monarch butterfly.
Avoiding predators - cont
d. Looking
scarey
2. Parasitism – one individual, the
parasite, feeds on another individual, the
host
a. Ectoparasites: live externally.
Ex. Fleas, ticks, lice, leeches,
lampreys
b. Endoparasites:
live internally.
Ex. Flukes,
tapeworms,
disease-causing
bacteria
Highly
adapted –
may lack
digestive
system,
limbs, etc
4. Competition – results from the use of
same resources by 2 or more species.
5. Mutualism –
cooperative
relationship
between 2
organisms in which
both benefit.
Ex. Sea anemone
and clown fish;
Acacia tree and ant
6. Commensalism – interaction in which
one species benefits, the other is not
helped or harmed
Ex. Cattle and egrets
Communities Change
Succession –
gradual
regrowth of
species in an
area
A. Primary – development of
community in an area not previously
inhabited.
Ex. New island (bare rock), sand
dune, lava flow
• http://bcs.whfreeman.com/thelifewire/conte
nt/chp55/55020.html
• Primary succession of a moraine
B. Secondary – replacement of species
after a disruption (by fire, storm,
human activity)
Pioneer species – the first to appear in
succession;
small and fast growing
Ex – lichen
Climax Community – Stable, mature
ecosystem. Stays the same a long time.
Ex – Forest, prairie
Pioneer
Climax