Download The Biosphere

Unit 1: Ecology
The flow of energy through
an ecosystem is one of the
most important factors that
determines the system’s
capacity to sustain life.
Adenosine Triphosphate (ATP)
 ATP



:
Adenine
Ribose
3 phosphate groups
– the bonds between
the phosphates are
where the energy is
stored – bonds must
be broken to release
the energy
Reminder: ATP/ADP Cycle
Interactions and Interdependence
 Ecology

The study of interactions and
relationships between organisms
and their environment.
Interactions and Interdependence
 What
non-living things in their environment
do organisms interact with?

Sunlight, air, water, soil, rocks
 In
what ways are these nonliving things
essential to organisms?

Photosynthesis, Oxygen in air, bacteria live in
soil, mosses on rocks, etc.
Biosphere
 Contains
the combined portions of the
planet in which all of life exists, including
land, water, and air (atmosphere)
Levels of Organization
Producers
 Sunlight
is the main energy source for life
on Earth.
Producers
 Producers
are also known as autotrophs
– they make their own food
 Two types:


Photo-autotrophs: use sunlight in process of
photosynthesis
Chemo-autotrophs: use inorganic chemicals
Producers -- Energy from the Sun
 Photosynthesis

Using light energy to power chemical
reactions to turn Carbon Dioxide (CO2) and
water into Oxygen(O2) and sugars.
 6CO2
+ 6H2O
Light energy
6O2 + C6H12O6
Producers -- Energy from the Sun
 On
land, plants are the main
autotrophs.
 In
freshwater ecosystems, algae
are the main autotrophs
Cellular Respiration
 Cellular
respiration: Both
autotrophs & heterotrophs
perform this to release energy
from food to do cellular work.
 6O2 + C6H12O6 --> 6CO2 + 6H2O
Biochemical pathways
Consumers
 Heterotrophs


Consumers that rely on other organisms for
their energy and food supply.
Indirect use of sun’s energy
Consumers -- Heterotrophs
 Herbivores
— eat plants (rabbit)
— eat other animals
 Omnivores — eat both plants and animals
 Detritivores — feed on plant and animal
remains called detritus.
 Decomposers — break down organic
matter (bacteria and fungi).
 Carnivores
Feeding Relationships
 Energy
flows through an ecosystem in one
direction:
Sunlight
Producers  Consumers
Energy Transformations
 Only
10% of the energy at each trophic level
is passed on to the next:




Primary – 1st
Secondary – 2nd
Tertiary – 3rd
Quaternary – 4th
 The
other 90% is lost as heat when
consumers burn food during cellular
respiration (this is good because it helps us to
maintain our body temperature!)
Trophic Levels
Food Chain
A
series of steps in which organisms
transfer energy by eating and being
eaten; travels in one direction.
 Always begins with producers who store
energy in the chemical bonds of the
foods they make.
 Stored energy is passed on to consumers
when they eat producers or other
consumers.
Feeding Relationships

Food Web

A network of feeding
relationships in an
ecosystem
Aquatic Food Web
Ecological Pyramids
A
diagram that shows the relative amounts
of energy or matter contained within each
trophic level in a food chain.



Energy Pyramid
Biomass Pyramid
Pyramid of Numbers
Ecological Pyramids
Energy Pyramid
Shows the relative amount of
energy available at each trophic
level. Organisms use about 10
percent of this energy for life
processes. The rest is lost as
heat.
Biomass Pyramid
Represents the amount of
living organic matter at each
trophic level. Typically, the
greatest biomass is at the
base of the pyramid.
Pyramid of Numbers
Shows the relative number of
Individual organisms at each
trophic level.
Recycling in the Biosphere
 Matter
and energy move differently
through the ecosystem.


Energy flows one way – some is lost as heat,
only 10% of energy is used directly by
organisms at each trophic level
Matter is RECYCLED through the ecosystem
• Law of Conservation of Matter
• Matter can be transformed
Ecosystems, Communities, &
Population Growth
Factors in an Ecosystem
Biotic factors: living organisms with
which an organism might interact.


Ex: insects, plants, etc.
Abiotic Factors: physical or nonliving
factors with which an organism might
interact.


Ex: sunlight, wind, soil, etc.
List the Biotic Factors in the picture
List the Abiotic factors in the picture
Community Interactions

Competition occurs when organisms
attempt to use an ecological resource in
the same place and at the same time.


Resource = any necessity of life
Examples: water, nutrients, light, food,
space
Community Interactions


Predation occurs
when one
organism
captures & feeds
on another
organism
Ex: lions hunt
deer
Community Interactions

Symbiosis: 3 main types



Mutualism = both organisms benefit from
the relationship
Commensalism = one organism benefits
while the other organism is neither helped
nor harmed
Parasitism = one organism benefits at the
expense of the other organism
Mutualism
Butterflies and flowers
Commensalism
Barnacles on a Whale
Parasitism
HEARTWORMS
Ecological Succession
Predictable changes that occur in a
community over time


Primary succession: occurs on surfaces
where no soil exists
 Examples: after a volcanic explosion
where the land is covered with lava or
ashes or on bare rock exposed by glacier
melt
 Pioneer species: first species to populate
the area (often lichens)
Primary Succession
Ecological Succession

Secondary succession: follows a
disturbance that changes an
existing community without
removing the soil
 Example: wildfires, plowing,
logging industry
Population Growth

Affected by 3 factors:



# of births
# of deaths
# of organisms arriving or leaving:
Immigration and emigration
Exponential Growth

Exponential growth occurs when
organisms in a population reproduce at a
constant rate
 Tends to happen when resources are
unlimited
 Example – bacteria
 2 split to become 4
 4 split to become 8
 8 split to become 16 and so it grows
on & on
Exponential Growth
Logistic Growth
Happens when resources become less
available so growth will slow or stop

Notice the pattern

When does the
growth slow & when
does it level out?
