Download Ecology - Lamar County School District

Ecology
 ECOLOGYthe branch of biology that studies the
interactions between organisms and their
environment.
 Ecological studies reveal interrelationships
between living and non-living parts of the
world.
Components of a Biosphere
 1) population:
 * includes all the members of a species in a
given area
ex. all of the white tail deer in the Honey Island
Swamp is a population
 2) community:
 * all of the populations in a given area
ex. all of the organisms in the Honey Island
Swamp-- deer, palmetto bushes, rabbits,
cypress trees, squirrels, raccoons, birds
blackberries, etc... is a community
Cont…
 3) ecosystem:
 * the living (biotic) community and the nonliving
(abiotic) physical environment functioning
together is an ecosystem
ex. the swamp ECOSYSTEM is made up of the
BIOTIC community and the ABIOTIC factors-weather, rocks, water, soil
 4) biosphere:
 * the biosphere is the portion of the earth in
which LIFE exists
* is made up of many complex ecosystems
* ALL OF THE ECOSYSTEMS COMBINED
MAKE UP THE BIOSPHERE!
Write in notes as a flow map
ALL ABOUT ECOSYSTEMS
* the ecosystem is the
structural and functional
unit that is studied in
ecology
* they involve important
interactions between biotic
and abiotic factors
* an ecosystem can
support itself and is stable
(not much change) when
three conditions are
met...the E.A.R.
conditions...
E.A.R Conditions
 1) there must be a constant supply of Energy
(the sun is this source for all life on earth)
 2) there must be living organisms that can
convert the energy into organic compounds
(plants--Autotrophs--photosynthesis)
 3) there must be a Recycling of materials
between organisms and the environment. A
balanced aquarium is an example of a very
small ecosystem.
 It is self-supporting because the requirements
for a stable ecosystem are present:
Cont..
 ENERGY (1) is supplied to the
ecosystem by light. There are PLANTS
(2) to change the light energy into the
organic molecule of energy (glucose).
RECYCLING (3) of materials occurs
during photosynthesis and respiration.
 During
 photosynthesis, plants
use light energy and
carbon dioxide to form
glucose. They give off
oxygen. Animals release
the carbon dioxide that
is used by plants.
PARTS OF AN ECOSYSTEM
 A) ABIOTIC FACTORS
 * the non-living parts of the environment
(water, air soil, rocks etc.)
 * they directly affect the ability of organisms to
live and reproduce
* abiotic factors can vary from place to place
 * abiotic factors can act as LIMITING FACTORS
that keep a population at a certain level
 ex. desert environment -- hot temperature and
little water are examples of limiting factors -different species living in the desert are LIMITED
mainly to those types of plants and animals that
need very little water and can survive extreme
temperatures
 B) BIOTIC FACTORS
 * all the living things that directly or
indirectly affect the ecosystem
(all living components-plants animals,
microorganisms)
 * biotic factors interact with other living
organisms and the physical environment
 * can also be LIMITING FACTORS
 ex. disease (bacteria), predators, food
resources
1) Nutritional Relationships:
 * involves the transfer of nutrients from
one organism to another within an
ecosystem
 a) AUTOTROPHS-* organisms that can synthesize organic
molecules from inorganic molecules
* also called producers
* can be either photosynthetic or
chemosynthetic
b) HETEROTROPHS-* organisms that cannot manufacture organic
molecules
* there are 5 types of heterotrophs
 i. HERBIVORES-* organisms that eat only
producers (plants)
* also called a primary or firstlevel consumer
ex. cows, elephants, goats
 ii. CARNIVORES-* organisms that eat only
other animals
* also called a secondary (or
tertiary--3) consumer
ex. tigers, lions, wolves
 iii. OMNIVORES-* organisms that eat everything
* can be a 1st, 2nd, or 3rd level
consumer
ex. bears, humans
 iv. SCAVENGERS-* organisms that eat only other
animals after they are already killed
* usually a 2nd or 3rd level
consumer
ex. vultures, hyenas
 v. DECOMPOSERS-* organisms that live on DEAD
matter
* also called saprophytes
ex. include heterotrophic plants,
fungi, and bacteria
 FOOD CHAIN * always starts
with producers
* shows the
pathway of energy
from one organism
to the next in a
direct line of
organisms.
 FOOD WEB
* shows the
interactions and
interconnections
among the different
food chains of a
community.
Food web in an ecosystem
2) Symbiotic Relationships:
 * an interaction among different species
in an ecosystem that where they live in a
close association with each other
* called SYMBIOSIS; at least one
member of the association benefits
(gains) by the association
 a) MUTUALISM (+ , +)
* a symbiotic
relationship in which
both organisms
BENEFIT
ex. nitrogen fixing
bacteria that live in
nodes (lumps) on the
roots of certain plants
(legumes)...the
bacteria have a nice
place to live (+), and
the plants benefit from
getting the nitrogen
they need from the
bacteria (+)
 b) COMMENSALISM (+ ,
0)
* a symbiotic relationship
where one organism
benefits (+) and the other
organism is not harmed (0)
ex. the remora (a small
fish) attaches itself to the
underside of a
shark...when the shark
feeds, the remora
disconnects and eats
scraps that are left over (+)
... the shark is not affected
(0)
 c) PARASITISM (+ , -)
* a symbiotic relationship
where one organism, the
parasite, benefits (+), while
the other organism, the host,
is harmed (-)
ex. athlete's foot, a fungus,
grows on human feet for
nutrients (+), while the human
doesn't like it (-);
tapeworms (+) in humans (-);
heartworms (+) in dogs (-)
 d) PREDATOR-PREY (+, -)
* a symbiotic relationship
where one organism eats
another!
ex. predator--lions (+), prey-gazelles (-)
ENERGY AND MATERIAL
CYCLES IN AN ECOSYSTEM
 in order for an ecosystem to be selfsustaining, it must have a continuous flow
of energy and be able to recycle materials
 A) energy pyramid:
 * at each step of the food web, energy is
transferred to the next higher level
* sun--->plant-->rabbit--->snake--->hawk
* this energy transfer is NOT
EFFICIENT!
* only 10% of the energy is passed to the
next generation to be used; most energy is
lost in maintaining homeostasis and as the
production of heat
* the amount of usable energy decreases
at each higher feeding level
 B) biomass pyramid:
 * the amount of organic matter in an
ecosystem is its BIOMASS
 (producers make biomass)
* the biomass pyramid shows the total
amount of biomass at each feeding level
* the higher the level, the less the
biomass...which is because there is less
energy at this level
C) material cycles
 1) CARBONOXYGEN CYCLE
* involves the
processes of
photosynthesis (uses
CO2 and produces
O2) and respiration
(uses O2 and
produces CO2)
 WATER CYCLE
* involves the
processes of
photosynthesis,
transpiration
(movement of water
through a plant),
evaporation and
condensation,
respiration, and
excretion
 3) NITROGEN
CYCLE
* involves
decomposers and
other soil bacteria
which break down
and convert
nitrogenous wastes
and the remains of
dead organisms into
material that is
usable by autotrophs
(nitrates)