ecology notes - wadsworth.k12.oh.us
TRANSCRIPT
Ecology Environmental Interactions
What is ecology?
• “Eco”= environment, house
• “Ology”= study of
• Ecology- the scientific study of interactions
among organisms and their environment or
surroundings
• The study of ecology looks primarily at the
biosphere, or area where all life exists.
• “Bio”= Life
• “Sphere”= circle, zone
How do we organize and group
life?
• A species is a group of organisms so
similar to one another that they can
breed and produce fertile offspring
• A species is the most specific grouping
of life
• Example= grey wolf
• All the wolves that live in one area
would be called a population, or group
of individuals that belong to the same
species and live in the same area.
• If we wanted to look at all the
different populations that live
in an area, we would be
looking at a community, or the
assemblage of different
populations that live together
in a defined area.
• Keep in mind that a
community only involves the
living, or biotic factors!!
Ex. All the animals and plants in a
forest
Bringing it all together…
• The next level of
organization is the
ecosystem.
- In an ecosystem, we
study a collection of all
the living organisms that
live in a particular place
together with their
nonliving, or abiotic,
environment.
Ex. Forests
The final step…
• The final and largest level of
organization (excluding the biosphere),
is the biome.
• Biomes are groups of ecosystems that
have the same climate and similar
dominant communities…
Biomes of the World…
• Tropical Rainforest
• Tropical Dry Forest
• Tropical Savanna
• Temperate Grassland
• Desert
• Temperate woodland and scrublands
• Temperate Forest
• Northwestern coniferous forest
• Boreal Forest (Tiaga)
• Tundra
• Mountains and Ice Caps
• Bodies of Water
What makes them unique and
different from one another?
• Location around the globe
• Climate
• Dominant plant and animal species
Tropical Rainforest
– Climate: hot, wet
– Soil: thin, poor
– biodiversity: high
Tropical Dry Forest
– Climate: warm, alternating wet and dry
– Soil: rich
– biodiversity: average
Tropical Savanna
– Climate: warm, seasonal rainfall
– Soil: compact
– biodiversity: average
Deserts
– Climate: variable temps., low rainfall
– Soil: rich in minerals, poor in organics
– biodiversity: average to low
Temperate Grasslands
– Climate: warm summers and cold winters,
moderate precipitation
– Soil: fertile
– biodiversity: average
Temperate Woodland and
shrubland
– Climate: warm, dry summers and cold,
moist winters
– Soil: thin, poor
– biodiversity: average
Temperate Forest
– Climate: warm summers and cold winters,
year round precipitation
– Soil: fertile
– biodiversity: average
Northwestern Coniferous Forest
– Climate: mild temperatures, abundant
precipitation fall, winter, and spring
– Soil: rocky, acidic
– biodiversity: average
Boreal Forest
– Climate: mild summers and long, cold
winters, moderate precipitation
– Soil: acidic, poor
– biodiversity: average
Tundra
– Climate: short, soggy summers and long,
dark, cold winters, low precipitation
– Soil: poorly developed, permafrost
– biodiversity: low
And the rest…
• Mountains
• Ice Caps
• Aquatic Biomes
– Oceans
– Lakes
– Rivers
– Ponds
– Etc.
Let’s go to the video…
• Biomes
Energy Flow Through an
Ecosystem
Ways of acquiring energy
• Autotrophs- can make their own
energy by converting the energy of the
sun into food. These organisms are
also called producers.
Acquiring Energy Con’d
• Heterotrophs- Organisms that get
their energy by consuming other
organisms. Also known as
consumers.
Can an organism be both???
• YES!!!
– Venus flytrap
– sun dew
– Pitcher plant
One more way to “power up”
• Chemotrophs are able to combine
different chemical compound (without
light) to make power. This process is
called chemosynthesis.
How they all interact…
• When an organism obtains energy by
eating only plants, it is called a
herbivore…
• If they eat only meat, they are
carnivores…
• Eating plants and meat make an
organism an omnivore…
Bottom Feeders…
• Detritivores feed on the remains of
plants and animals along with other
dead material called detritus.
• This includes worms, snails, mites,
and….
crabs
“Stinky dead animals,” brought
to you by…
• Decomposers- break down organic
matter
• Examples: bacteria, fungus
Putting them all together…
• Feeding relationships are shown using
two different graphs, food chains and
food webs.
– Food chains show a series of steps in
which organisms transfer energy by
eating and being eaten.
Webs…
• Food webs are a network of complex
interactions that show feeding
relationships.
– Webs are better at showing actual
interactions on a large scale
The levels of organization
• Each step in a food chain is called a
trophic level.
• They go as follows: Top level carnivores
1st level carnivores
herbivores
producers
Trophic levels
Trophic levels con’d
• Available energy at each level is
shown on an ecological pyramid.
• Numbers represent percentage of
original sunlight energy still available
for use…
• Available energy: – Producers= 100%
– Herbivores (primary consumers)= 10%
– 1st level carnivores (2ndary consumers)= 1%
– 2nd level carnivores (tertiary consumers)= .1%
Ecological pyramid
Community Interactions
A few terms…
• Biotic factors- biological (living)
influences on organisms within an
ecosystem • Ex. Trees, birds, people, etc.
• Abiotic factors- physical, or nonliving,
factors that shape ecosystems • Ex. Rivers, wind, soil, temperature, etc.
• Habitat- the area where an organism
lives
More terms…
• Niche- the full range of physical and
biological conditions in which an
organism lives and the way the
organism uses those conditions
– Baseball players – Each person on the field has a job and a specific
place to do that job, that is their “niche”
Resources
• Resources are necessities of life and
include water, nutrients, light, food and
space.
– What happens if two organisms both want
to use the same resources??
Resources
• This idea that no two species can
occupy the same niche in the same
habitat is called the competitive
exclusion principle.
• Though no two organisms can occupy
the same niche, they do interact in
many different ways.
Forms of interaction
• Predation- one organism captures and
feeds on another
• Symbiosis- any relationship where
two organisms live closely together
– Forms of symbiosis:
• Mutualism
• Commensalism
• Parasitism
Mutualism (+/+)
• This type of symbiosis provides a
benefit for both organisms involved
– Ex. Bees and flowers, hummingbird and
flowers, etc.
Commensalism (+/neutral)
• This type of symbiosis provides a
benefit for one organism involved but
doesn’t harm or help the other
organism
– Ex. Whales and barnacles, orchids and
trees, etc.
Parasitism (+/-)
• This type of symbiosis provides a
benefit for one organism involved but
harms the other organism
– Ex. Dog and flea, people and mosquitoes,
etc.
How do populations grow?
• - Populations are constantly changing
in number. A few ways this happens
are:
– Deaths
– Births
– Immigration
– Emigration
• All of these factors control the
population density, or number of
individuals per unit of area…
• Immigration (+)- the movement of an
individual into an area. Population
increases
• Emigration (-)- the movement of an
individual out of an area. Population
decreases
• One cannot happen without the other
In what ways do populations
grow?
• If unlimited resources are available, a
population will grow at an exponential
rate, or without limitation and at a
constant rate.
– growth starts at a low number but
increases quickly
• Example: a single bacterium lands on your
food, has offspring, who have offspring, who
have offspring and so on doubling their
numbers every 20 minutes
• a few become many...
Growth continued
• If for some reason resources do
become limited, our bacteria would
switch to a pattern of logistical growth,
or a time where a population’s growth
slows or stops after a period of
exponential growth.
– Could be caused be high death rate, low
birth rate, limited resources, etc.
Carrying Capacity
• All growth is controlled by
an imaginary number
called the carrying
capacity.
– Carrying capacity is the
maximum population
number an area can
support long term.
Ecological Succession
Changes over time…
• What is ecological succession?
– A series of predictable changes that
occurs in a community over time.
• As an ecosystem changes, older inhabitants
gradually die out and new organisms move in
causing further changes to the community
Primary Succession
• Succession that takes place where no soil
previously existed is called primary
succession.
– Soil is created through the weathering of rock
and breakdown of organic material
• May happen after a volcano or glacier
Primary succession
• The 1st species to populate this newly
created soil is called a pioneer
species.
– These species add organic material to the
nutrient poor soil as they die.
• Ex. Lichen (fungus + algae)
Secondary succession
• Succession that takes place following a
disturbance that destroys a community
without destroying the soil is called
secondary succession.
– What kind of disasters might do this??
• Floods, fires, hurricanes, tornadoes, etc.
Nutrient Cycling
Nutrients
• Nutrients are nature’s building blocks,
or all the chemical compounds that an
organism needs to sustain life.
• Essential nutrients include:
– Carbon - Iron
– Nitrogen - Zinc
– Phosphorus - Potassium
– Oxygen - Fluorine
– Hydrogen - Calcium
– Magnesium - many, many, others!!
Limited nutrients
• When an ecosystem is limited by a
single nutrient that is scarce or cycles
very slowly, that substance is called
the limiting nutrient.
– Three of the most common limiting
nutrients are:
• Nitrogen
• Potassium
• Phoshporus
– How do farmers deal with this problem??
Productivity
• Limiting nutrients along with overall
nutrient availability affect an
ecosystem’s primary productivity.
– This is the rate at which producers in the
ecosystem make organic matter
Cycling nutrients
• Matter is recycled between and within ecosystems.
What kinds of matter?
– Water
– Carbon
– Nitrogen
– phosphorus
• Biogeochemical cycles are the pathways that
elements, compounds, and other forms of matter
are passed from one organism to another or from
one area to another.
The Water Cycle
Moving H2O
• - Water is carried from the
clouds to ground through
precipitation.
• - As it moves across the
ground, some is taken back to
a gaseous form through
evaporation.
• - Plants lose small amounts of
water through transpiration.
• - As water accumulates, it
forms back into liquid water by
the process of condensation.
The Carbon Cycle
• A large percentage of carbon is found in the
atmosphere as CO2
• CO2 is collected by plants and turned into organic
tissue during the process of photosynthesis.
• This organic matter is eaten, broken down, and
given off as waste CO2 and returned to the
atmosphere
– It can also be burnt, which also gives off CO2
• When organisms die, the carbon stored in their
bodies returns to the atmosphere as CO2 as they
decay and returned to the soil as they decompose.