The Biosphere/ Ecology
Notes
What is Ecology?
• Scientific study of interactions
among organisms and between
organisms and their environment
Biosphere
– Combined portions of the planet in which all
of life exists, including land, water and air
or atmosphere
• Extends from 8 kilometers above Earth’s
surface to 11 kilometers below the surface
of the ocean
Interactions and Interdependence
• Interactions within the biosphere produce
a web of interdependence between
organisms and the environment in which
they live
Levels of Organization
– Individual: interactions between an organism
and its surroundings
• cottontail rabbit
– Population: groups of individuals that belong
to the same species and live in the same area
• group of cottontail rabbits
Levels of Organization
– Communities: different populations that live
together in a defined area
• rabbits, coyotes, ravens, lizard
– Ecosystem: collection of all the organisms
that live in a particular place, together with
their nonliving, or physical, environment
• rabbits, coyotes, ravens, lizard, rocks, dirt,
climate, water
Levels of Organization
– Biome: group of ecosystems that have the
same climate and dominant communities
• desert, tundra, tropical rain forest
– Biosphere: planet Earth
Ecological Methods
– Three approaches to ecological research:
• Observing: Use of 5 senses to ask
ecological questions
• Experimenting: Used to test hypotheses
– artificial environment in a lab
– within natural ecosystems
Ecological Methods
– Modeling: Used to gain insight into
complex phenomena such as the effects
of global warming
– may include mathematical formulas
based on data collected through
observation and experimentation
– predictions tested by further observations
and experiments
Biotic and Abiotic Factors
• Click on link to see video clip
Biotic Factors
• ‘Bio’- Means ‘life’
• Definition - organisms
that make up the living
portion of an ecosystem
• Also considered the
ORGANIC component
of the ecosystem
• Ex. Trees, shrubs,
insects, animals, algae,
fungi, etc
Abiotic Factors
• ‘Abio’ – Means ‘not
life’
• Definition – the
nonliving features of an
environment
• Considered the
INORGANIC
component of the
ecosystem
• Ex. Air, temperature,
moisture, light, rocks,
and soil
Energy Flow
• Energy flows from the sun or inorganic
compounds to producers.
• Consumers eat producers to get energy.
• The primary source of energy on Earth is the
sun!!
Every Organism Has a Home Address
Habitat
• Definition – physical
location in which an
organism lives
• In other words the home
address of a species
• Ex. Fern habitat –
moist, shady forest
floor.
Habitat
• Many animals can share a
habitat
• A single tree maybe the
habitat for several species of
birds, squirrels, etc.
• However, each species uses
the habitat in a different
way.
• They all find their niche
•
Coral reef biodiversity.
Niche
• Definition – the way a
species uses the
resources of its habitat
and what it does in the
community
• Includes: food, living
space, methods of
obtaining food, etc.
• NO TWO SPECIES
CAN OCCUPY THE
SAME NICHE
Producers
• Autotrophs – “self feed”
• Use sunlight to create carbohydrates via
photosynthesis
• Ex – Plants, algae and some bacteria
• Some bacteria create organic compounds from
inorganic chemicals – Chemosynthesis
– Live in remote places.
PRODUCERS
Producers make their own food!
They are also called autotrophs
Level 1 on the Trophic Level
Plants and bacteria make up this
group.
• They make their food from the sun
called photosynthesis
•
•
•
•
Producers
CONSUMERS
• Consumers are living things that cannot make
food for themselves. (Also called heterotrophs)
• They survive by taking in food that has been
made by other living things.
• A food chain contains several kinds of
consumers.
• Heterotroph – “Different food”
• Must eat to obtain energy.
• Ex – animals, fungi, some protists
• YOUR MOM’S A HETEROTROPH!!!
Types of Heterotrophs
•
•
•
•
Herbivore – eats plants
Carnivore – eats animals
Omnivore – eats plants and animals
Detritivore – eats detritus (plant and animal
remains)
– Ex- snails, crabs, earthworms
• Decomposer – breaks down organic matter
– Ex – bacteria and fungi
Carnivore
Decomposers
Omnivore
Detritivore
Feeding Relationships
Energy flows through an ecosystem in one
direction,
 from the sun or inorganic compounds 
autotrophs (producers)  various
heterotrophs (consumers).
Energy flows…
• Flows in one direction
• Will never return to the same
form in the ecosystem
• Conservation of Energy:
– Energy changes form
– But is never lost
What happens to all the energy?
• When an organism eats another organism,
energy is either:
– stored in the tissues of the organism doing the
eating,
– used by the organism, or
– released as heat.
Food Chain
– A series of steps in which organisms transfer
energy by eating and being eaten.
• i.e. Wheat  mouse  snake  hawk
Food Web
• Network of complex interactions formed
by the feeding relationship among the
various organisms in an ecosystem.
Ecological Pyramid
• A diagram that shows the relative
amounts of energy or matter contained
within each trophic level in a food chain
or food web.
• Energy, biomass, and population numbers
can all be represented by a pyramid.
Ecological Pyramid
Only about 10% of the energy from one trophic
level is stored in the next.
Matter is recycled in ecosystems.
Matter cycles…
• Matter can be recycled
• Matter can be reformed
• The basic building
blocks are reused
• Conservation of Matter
• The Law of Conservation of
Matter states that matter
cannot be created or
destroyed only transformed
from one form to another.
The four most abundant elements in living
things are…
H
Hydrogen
O
Oxygen
N
Nitrogen
C
Carbon
Cycles of Matter
• Recycling in the Biosphere
– Matter is recycled within and between
ecosystems.
– Matter moves through an ecosystem in
biogeochemical cycles.
Water Cycle
Carbon
Cycle
How carbon is cycled through organisms…
•
Photosynthesis vs. Respiration
• Photosynthesis is the process by which producers
convert radiant energy from the sun into chemical
energy in the form of glucose (food).
• Cellular respiration is done by both producers and
consumers. It uses oxygen to break down glucose
into carbon dioxide and water, releasing energy in the
process.
Nitrogen Cycle
N2 in Atmosphere
NH3
NO3and NO2-
Nitrogen Cycle
– 78% of Earth’s atmosphere is Nitrogen gas = N2
• Nitrogen containing products:
–Ammonia (NH3)
–Nitrate ions (NO3-)
–Nitrite ions (NO2-)
• Nitrogen is needed for protein and nucleic acid
synthesis
Nitrogen Cycle
– Converting nitrogen gas into ammonia is called
nitrogen fixation.
• Only certain types of bacteria can do this.
• Plants use the converted products (NH3,
NO3- ,& NO2-) to make plant proteins.
– Some bacteria convert nitrates into nitrogen gas
(denitrification).
Phosphorus Cycle
Phosphorus Cycle
– Phosphorus is important for the formation of
DNA and RNA molecules.
– Phosphorus is not very common and does not
enter the atmosphere, instead it is found mostly
on land in rock and soil.
Primary Productivity
• The rate at which producers create organic
matter.
• Determines the size of the community.
• Limited by availability of nutrients.
– Land – phosphorus (P), nitrogen (N), potassium
(K)
– Marine – nitrogen
– Fresh water - phosphorus
Algal Bloom
Algal Bloom Details
• An algal bloom is a rapid increase or accumulation in the
population of algae (typically microscopic) in an aquatic system.
Algal blooms may occur in freshwater as well as marine
environments. Typically, only one or a small number of
phytoplankton species are involved, and some blooms may be
recognized by discoloration of the water resulting from the high
density of pigmented cells. Although there is no officially
recognized threshold level, algae can be considered to be blooming
at concentrations of hundreds to thousands of cells per milliliter,
depending on the severity.
• A harmful algal bloom (HAB) is an algal bloom that causes
negative impacts to other organisms via production of natural
toxins, mechanical damage to other organisms, or by other means.
HABs are often associated with large-scale marine mortality events
and have been associated with various types of shellfish poisonings.
HAB Dangers
•
•
•
•
the production of neurotoxins which cause mass
mortalities in fish, seabirds, sea turtles, and marine
mammals
human illness or death via consumption of seafood
contaminated by toxic algae
mechanical damage to other organisms, such as
disruption of epithelial gill tissues in fish, resulting
in asphyxiation
oxygen depletion of the water column (hypoxia or
anoxia) from cellular respiration and bacterial
degradation
HAB commonly referred to Red Tide
HAB effects