2. 18.1
Ecology – study of interactions
between organisms and
environment.
Consists of abiotic (nonliving;
i.e. temperature, light, etc) and
biotic (living) factors.
3. Levels of Organization
The levels of
organization are
designed to allow
scientists to
understand and
study relationships
more easily
4. Levels of Organization
smallest unit
of living
things
group of
similar cells
organized to
work together
group of
different
kinds of
tissues
working
together
group of
organs
working
together
one individual
living thing
all organisms
of the same
kind living in
one area
all interacting
populations in
an ecosystem
all living and
nonliving
things
interacting
within a
certain area
large region
with typical
plants and
animals that
includes
several
ecosystems
cell
5. Species – a group of organisms
that can breed and produce fertile
offspring
6. Populations – groups of
individuals that are the same
species and living in the same area
7. Communities – a group of
organisms of different species living
together in the same area
8. Ecosystems – all the populations
living together with the nonliving
environment
9. Biomes – groups of similar
ecosystems that have similar
climates and similar communities
16. Organisms in a changing
environment
Each organism can survive within a limited
range of environmental conditions
Tolerance curve- a graph of performance
versus values of an environmental variable
such as temperature
Acclimation- the process of an organism
adjusting tolerance to abiotic factors
17. Organsims can survive unfavorable
environmental conditions through:
Dormancy- entering a state of reduced
activity
Migration-moving to a favorable habitat
18. Structure
Habitat – the physical area in which an
organism lives (includes climate,
topography, soil and water chemistry,
plant and animal life, etc.)
Niche – the way of life of a species
(includes its habitat, feeding habits,
reproductive behavior, etc.)
species can be generalists (broad
niche) or specialists (narrow niche)
20. All energy comes from the sun
Plants harness the sun’s
energy in which process?
21. Plants need light for
photosynthesis, what else do they
need?
We call plants producers
because they produce
energy from the sun
22. Measuring productivity
Gross primary productivity-rate at
which producers in an ecosystem
capture energy of sunlight by
producing organic compounds
Biomass-organic material produced in
an ecosystem
Net primary productivity-rate at which
biomass accumulates
23. Primary Producers (Autotrophs)
Energy from the sun is captured
by plants, algae, or bacteria
through photosynthesis.
Energy from chemicals is
captured by some bacteria
through chemosynthesis.
Capture energy from the sun or
from chemicals and store it in
the bonds of sugars, making it
available to the rest of the
community Did You Know? Deep-sea vents, far from sunlight,
support entire communities of fish, clams, and
other sea animals, which depend on energy
converted through chemosynthesis.
24. Consumers (Heterotrophs)
Rely on other organisms for energy
and nutrients
Use oxygen to break bonds in sugar
and release its energy through cellular
respiration (primary producers do this,
too)
Types of Consumers:
Herbivores: plant-eaters
Carnivores: meat-eaters
Omnivores: combination-eaters
Detritivores and decomposers:
recycle nutrients within the
ecosystem by breaking down
nonliving organic matter
California Condor
Did You Know? Scavengers, such as
vultures and condors, are just large
detritivores.
25. When one organisms eats another,
molecules are metabolized and energy is
transferred
An organism’s trophic level indicates the
organism’s position in a sequence of
energy transfers
27. Energy in Communities
An organism’s rank in a
feeding hierarchy is its trophic
level.
Primary producers always
occupy the first trophic level of
any community.
In general, only about
10% of the energy available at
any trophic level is passed to
the next; most of the rest is
lost to the environment as
heat.
Lesson 5.3 Ecological Communities
Pyramid of Energy
28. What is a food chain?
Food chain: Linear series
of feeding relationships
29. A Basic Food Chain
Plants absorb light from the
sun, which is turned into
energy to grow. We call
these producers.
The vegetarian animals eat
the plants, they are called
primary consumers.
Secondary consumers
prey on primary
consumers.
31. MATTER CYCLING IN
ECOSYSTEMS
Nutrient Cycles: Global Recycling
Global Cycles recycle nutrients through the
earth’s air, land, water, and living organisms.
Nutrients are the elements and compounds
that organisms need to live, grow, and
reproduce.
Biogeochemical cycles move these substances
through air, water, soil, rock and living
organisms.
33. Water Cycle Key Terms:
Ground water-water found in soil or in
underground formations of porous rock
Transpiration-process by which water
evaporates from leaves of plants in
terrestrial ecosystems
Evaporation-adds water to the atmopshere
Precipitation-the process by which water
leaves the atmosphere
35. Carbon Cycle
Fourth most abundant element in universe
Building block of all living things
Main Pathway– in and out of living matter
36. Key Terms
Carbon Cycle- Circulation of carbon
through ecosystems
Carbon- A non-metallic element found in
coal, petroleum and natural gas. Major
component of life.
Soil Respiration- Carbohydrates are
oxidized and returned to the air by soil
microorganisms that decompose dead
animals
37. Key Terms Continued
Atmosphere- layer of gasses
Fossil Fuels- Carbon-rich fuel from ancient
animals and plants
Photosynthesis- Energy (sun)+ Water+
Carbon dioxide Carbohydrates+ Oxygen
Cellular Respiration- Glucose+ Oxygen
CO2+ H20+ Energy (ATP)
Decomposition- breakdown of matter by
bacteria and fungi
38. Biological Importance of Carbon
All living organisms contain carbon
CO2 is found in all living organisms
Plants use carbon dioxide and water to
form simple sugars (photosynthesis)
Carbon is needed for life
Carbon dioxide is a greenhouse gas
Carbon is necessary for life, but carbon
dioxide can be harmful
40. Nitrogen cycle
Organisms need nitrogen to make proteins and
nucleic acids
Nitrogen gas makes up 78% of the atmosphere
Most plants can only use nitrogen in the form of
nitrate
Nitrogen fixation- process of converting nitrogen
gas into nitrate
Nitrogen fixing bacteria transform nitrogen into
a usable form
41. Recycling nitrogen
Decomposers break down decaying organisms
and release the nitrogen they contain as NH3
Ammonification- changing NH3 (ammonia) into
NH4
+(ammonium)
Nitrification-soil bacteria take up ammonium and
oxidize it into (nitrites) NO2
-and (nitrates) NO3
-
Denitrification-process where anaerobic bacteria
break down nitrates and release nitrogen gas
into the atmosphere
43. Importance of the Phosphorus
cycle
Phosphorus is an essential nutrient for
plants and animals
It is a part of DNA-molecules and RNA-
molecules, molecules that store energy
(ATP and ADP)
Phosphorus is also a building block of
certain parts of the human and animal
body, such as the bones and teeth.
44. Difference in the Phosphorus cycle
The phosphorus cycle differs from the
nitrogen and carbon cycles because
phosphorus is unable to achieve the
gaseous state in the atmosphere.
Phosphorus is mainly found in water, soil
and sediments. In the atmosphere,
phosphorus is found as fine dust particles.
47. Ch 19 Populations
19.1 Understanding populations
Population ecology: studies changes in population size
and the factors that regulate populations over time
A. Populations are affected by size, density and dispersion
1. Population size- number of individuals
2. Population density: the number of individuals of a
species per unit area or volume
Ex: number of earthworms per cubic meter of soil
Normally determined by sampling
Estimates are more accurate for larger populations
48. 3. Population dispersion
a. Clumped dispersion pattern: individuals are
grouped in patches
Most common in nature
Due to unequal distribution of
resources in the environment
b. Uniform dispersion pattern: even spreading
Usually results from interaction
between individuals
Ex: territories
c. Random dispersion pattern: unpredictable
spacing
Ex: plants grown from
windblown seeds
49. B. Population dynamics: interactions between biotic
and abiotic factors that cause variation in population
size
1. Population growth
Population increases occur through birth (natality)and
immigration
Immigration-movement of individuals into a population
Population decreases occur through death (mortality) and
emigration
Populations are also affected by life expectancy or how
long and individual is expected to live
Emigration-movement of individuals out of a population
May be influenced by factors such as food availability and water
quality
51. 3. Patterns of mortality
Survivorship: the chance of an individual in
a given population surviving to various
ages
Survivorship curves: plot survivorship as
the proportion of individuals from an initial
population that are alive at each age
Allows for species comparison
52. a. Type I survivorship: animals
that produce few offspring and
nurture them to maturity
Ex: humans and other large
mammals
b. Type III curve: opposite of a
Type I
Many offspring are produced
but few make it to maturity
Ex: many invertebrates
c. Type II curve: survivorship is
constant over the lifespan
Individuals are equally
vulnerable at every stage of
the life cycle
Ex: lizards and rodents
53. 19.2 Measuring Populations
A. Population size
Determined by the following equation:
Growth rate =(individuals added)- (individuals
subtracted)
or
(birthrate + immigration rate) – (death rate + emigration
rate)
Growing populations have a positive growth rate;
shrinking populations have a negative growth rate.
Usually expressed in terms of individuals per 1000
Population changes are expressed as percentages:
Growth rateX100= % growth
54. B. Exponential growth model:
the rate of population
growth under ideal
conditions
As the population size grows,
more individuals are added
during each interval
Graphing this data gives a J-
shape curve
Exponential growth can NOT
continue indefinitely
Eventually, one or more
environmental factors will
limit growth
Ex: space and food supply
55. C. Logistic growth model: idealized
population growth that is slowed by
limiting factors as the population size
increases
Results in formation of an S-shape
curve
K is the carrying capacity - maximum
population size that a particular
environment can sustain
K varies depending on the species
and the resources available
Influenced by predators, parasites,
food sources, and abiotic factors
Emphasizes that resources are finite
At low populations, resources are
abundant and the population is able
to grow nearly exponentially
Population stabilizes at the carrying
capacity when the birth rate equals the
death rate
56. D. Population Regulations
Density-independent factors- factors that reduce the
population by the same proportion. Influence does not
change with population density.
These are usually abiotic factors
They include natural phenomena, such as weather
events
Drought, flooding, extreme, heat or cold, tornadoes,
hurricanes, fires, etc.
Density-dependent factors- Influence changes with
population density.
Any factor in the environment that depends on the
number of members in a population per unit area
Usually biotic factors, these include:
Predation, Disease, Parasites, Competition
