Transcript ECOLOGY PART I

PART I
Definitions:
1. Ecology = branch of biology that deals with
interactions between organisms and their
environment and interactions among organisms
2. biotic factors = living factors in the environment
3. abiotic factors = physical factors in the
environment
4. limiting factor = physical factor in the
environment that limits population growth
Abiotic factors include:
1. light
• intensity and duration varies with latitude
• influences plant life and animal hibernation
and migration
• water has photic zone (where light penetrates)
• water has aphotic zone (no light)
* heterotrophs and chemotrophs
Abiotic factors include:
2. temperature
• varies with latitude and
altitude
3. Water
• precipitation varies region to
region
• varies with latitude and
altitude
• influenced by mountains and
oceans
Abiotic factors include:
4. soil and minerals
• soil layers
• topsoil – organic matter, living
organisms, plant liter (humus)
• subsoil – rock particles, mineral
and nutrients
• rock from bedrock below
Biotic relationships:
1. populations
• individuals of a certain species
in an area
• example = bullfrogs in a pond
2. community
• different populations in a given
area
• example = bullfrogs, algae, fish
in a pond
3. ecosystem
• community and physical
environment including biotic
and abiotic factors
Biosphere:
portion of the earth’s surface where living things
exist (about 20 km thick)
includes:
1. lithosphere – solid surfaces of the earth
2. hydrosphere – water (on, under, and vapor
over)
3. atmosphere – air mass
Complete worksheet
ECOSYSTEMS
On page 2 in your
packet
Nutritional Relationships
Autotrophic
(producers)
• Organisms that make their own food using
CO2
• Most use photosynthesis, a few use
chemosynthesis
• This provides food for the heterotrophs
Heterotrophs
(Consumers)
Organisms that cannot synthesize their
own food
1.
2.
3.
4.
Herbivores
Carnivores
Omnivores
Saprobes
Herbivores
• feed only on plants
• rabbits, cattle, deer, sheep, horses
Carnivores
feed on other animals (meat
eaters)
• Predators –attack and kill prey
(lions, hawks, wolves)
• Scavengers – feed on dead
animals that they find
(vultures, hyenas)
Omnivores
• feed on plants and animals
(bears, humans)
Saprobes (decomposers)
• organisms that obtain nutrients by breaking
down remains of dead plants and animals
(fungi and mushrooms)
Predator – Prey Curve
Predator population follows prey population
Symbiotic Relationships
• organisms that live in close association
with each other and at least one benefits
1. Mutualism
2. Commensalism
3. Parasitism
Mutualism:
both organisms benefit
• Termites and digestive organisms
• Cows and digestive organisms
• Lichens (algae and fungal cells)
• Peas, clover, alfalfa (legumes) have nodules of bacteria
on their roots that convert nitrogen gas into nitrogen in
the soil that can be absorbed by the plants
The alga provides food for the fungus,
which then envelops the alga,
providing shelter and nutrients.
Commensalism
one organism benefits
and the other is not
affected
• Pilot fish and sharks
• Barnacles on the body
of a whale
Parasitism
one organism benefits
and the other is
harmed
• Parasite and host
• Can cause slight damage
– some can kill
• Tape worm in animals
• Mistletoe and Indian pipe
in plants
Competition in ecosystems
• Habitat – where an
organism lives
• Niche – role of the species
in their ecosystem
• When niches overlap –competition begins
Intraspecific (within a species)
Interspecific (between species)
ENERGY FLOW
1. Food Chains
2. Food Webs
Food Chains
producer
consumer
consumer
consumer
(grass)
(grasshopper)
(frog)
(hawk)
Food Webs
• Shows all of the food chains in a community
Pyramid of
Numbers
Pyramid of Numbers
TOP
3RD
ORDER
CARNIVORS
2ND ORDER
1ST ORDER
HERBIVORS
PRODUCERS
GREEN PLANTS
NUTRIENTS
Lowest level is most numerous, most energy, most biomass
1. Numbers decrease going up the pyramid
2. Energy decreases going up the pyramid
• Only about 10% of the total energy is passed level to level
3. Total biomass decreases going up the pyramid
• Each level going up supports less numbers and less
biomass
3rd level
Consumer
Secondary
Consumers
Primary
consumers
producers
Complete worksheet
ECOSYSTEMS
On pages 6 and 7 in
your packet