STUDY GUIDE for Bio 1010 final exam
60% of the questions will be based on the new material taught since the last exam. The
remainder will be based on important and general principles from the rest of the course.
Chapter 27 Community Structure and
Biodiversity
27.1 Community
All the populations of species that live
together in a habitat
Habitat is the type of place where a species
normally lives
Habitat type shapes a community’s structure
Factors Shaping Community Structure
Climate and topography
Types of foods and resources available
Adaptations of species in community
Species interactions
Arrival and disappearance of species
Physical disturbances
Commensalism, mutualism, competition,
predation, and parasitism are all forms of
symbiosis
Niche—way of life
Sum of activities and interactions in which a
species engages to secure and use resources
necessary for survival and reproduction
Fundamental vs. Realized Niches
Fundamental niche
Theoretical niche occupied in the absence of
any competing species
Realized niche
Niche a species actually occupies
Realized niche is some fraction of the
fundamental niche
Mycorrhizae
Obligatory mutualism between fungus and
plant root
Fungus supplies mineral ions to root
Root supplies sugars to fungus
Species Interactions
Most interactions are neutral; have no effect
on either species (0/0)
Commensalism helps one species and has no
effect on the other (+/0)
Mutualism helps both species (+/+)
Interspecific competition has a negative
effect on both species (-/-)
Predation and parasitism both benefit one
species at a cost to another (+/-)
27.3 Competition (-/-)
Interspecific - between species
Intraspecific - between members of the same
species
Intraspecific competition is most intense
Competitive Exclusion
When two species compete for identical
resources, one will be more successful and
will eventually eliminate the other
Competitive Exclusion Expt
Resource Partitioning
Apparent competitors may actually have
slightly different niches
Species may use resources in a different way
or time
Symbiosis
Close association of two or more species
during part or all of the life cycle
27.2 Mutualism (+/+)
Both species benefit
Many examples in nature
Some mutualisms are obligatory; partners
depend upon each other
Lichen
Obligatory mutualism between fungi and
algae
Fungus supplies anchorage and water
retention
Alga supplies photosynthate
Yucca and Yucca Moth
Obligatory mutualism
Each species of yucca is pollinated by only
one species of moth
Moth larvae can grow only in that one
species of yucca
Minimizes competition and allows
coexistence
27.4 Predation (+/-)
Predators are animals that feed on other
living organisms
Predators are free-living; they do not take up
residence on their prey
Coevolution
Natural selection promotes traits that help
prey escape predation
It also promotes traits that make predators
more successful
“Arms race” between predators and prey
Predator and Prey Populations are related
Multi-level interactions
Carnivore-Herbivore-Plants
27.5 Evolutionary Arms Race
PREY DEFENSES
Camouflage
Warning coloration
Mimicry
Chemistry
Predator Responses
Any adaptation that protects prey may select
for predators that can overcome that
adaptation
Predator adaptations include stealth,
camouflage, and ways to avoid chemical
repellents
27.6 Parasitism (+/-)
Parasites drain nutrients from their hosts and
live on or in their bodies
Natural selection favors parasites that do not
kill their host too quickly
Biological Controls
Parasites are commercially raised and
released in target areas as biological controls
An alternative to pesticides
Must be carefully managed to avoid
upsetting natural balances
27.7 Skip
27.8 & 27.9 Succession
Change in the composition of species over
time
Pioneer Species
Species that colonize
barren habitats
Lichens
Annual plants
Grow well in sunny and dry conditions
Have many offspring, opportunistic,
“weedy”
Improve conditions for other species that
replace them (N-fixing)
Climax Community
Stable array of species that persists
relatively unchanged over time
Succession does not always move
predictably toward a specific climax
community; multiple stable communities are
possible
Keystone Species
A species that can dictate community
structure
Removal of a keystone species can cause
drastic changes in a community; can
increase or decrease diversity
Wolf-Elk-Aspen
27.10 Exotic Species
Species that has become established outside
of its natural home range
Becomes part of a new community
Exotic Species Introductions
Introduction of a non-indigenous (nonnative) species can be accidental or
intentional
EXOTIC SPECIES:
Have no natural enemies or controls
Can outcompete native species
Kudzu in SE United States
Magpie in Turlock
Tree-of-heaven in Turlock
27.11 Biodiversity
The sum of all species occupying a specified
area during a specified interval
Patterns of Diversity:Latitude
Diversity of most groups is greatest in
tropics; declines toward poles
a) ants
b) birds
Why are the Tropics species rich?
More sunshine, more rain, longer growing
season--resources are plentiful and reliable
Tropical species have been evolving for a
longer period of time than temperate species
Species diversity is self-reinforcing
27.12 Endangered Species
A species that is extremely vulnerable to
extinction
Habitat loss is the major cause of species
endangerment and extinction
Endangered Species Recovery Program at
CSU Stanislaus
http://esrp.csustan.edu/
San Joaquin kit fox
Riparian brush rabbit
California jewelweed
Kern mallow
Indicator Species
Types of species that may warn of
impending loss of biodiversity
Birds, amphibians
27.13 Conservation Biology
Study of biological diversity
Methods of preserving biodiversity
Ways to utilize biodiversity sustainably
27.13 Preserving Biodiversity
Requires identifying and protecting regions
that support the highest levels of
biodiversity
It is possible to protect a habitat and still
withdraw resources in a sustainable way
Areas at Risk
Chapter 28 Ecosystems
28.1 Ecosystem
An association of organisms and their
physical environment, interconnected by a
flow of energy and a cycling of raw
materials
Modes of Nutrition
Autotrophs
Capture sunlight or chemical energy
Producers
Heterotrophs
Extract energy from other organisms or
organic wastes
Consumers
Simple Ecosystem Model
Trophic Levels
Food Chain
A straight line sequence of who eats whom
Simple food chains are rare in nature
Food Web
28.2 Energy Losses
Energy transfers are never 100 percent
efficient
Some energy is lost at each step
Limits the number of trophic levels in an
ecosystem
Biomass Pyramid
Energy Pyramid
Primary producers trap about 1% of the
solar energy that enters an ecosystem
Only ~10% is passed on to next level
All Heat in the End
At each trophic level, the bulk of the energy
received from the previous level is used in
metabolism
This energy is released as heat energy and
lost to the ecosystem
28.3 Biological Magnification
A nondegradable or slowly degradable
substance becomes more and more
concentrated in the tissues of organisms at
higher trophic levels of a food web
Ex: DDT and Mercury
DDT in Food Webs
Synthetic pesticide used in the US before the
1970s
Birds that were top carnivores accumulated
DDT in their tissues
A side effect of DDT is brittle egg shells
Rachel Carson
Author of “Silent Spring” (1962)
Awakened public interest in limiting the use
of pesticides
28.4 and 28.5 Skip
28.6 Biogeochemical Cycles
The movement of an element from the
environment to living organisms and back to
the environment
Main reservoir for the element is in the
environment
28.7 Hydrologic Cycle
Watershed
Any region where precipitation flows into a
single stream or river.
Ex: Mississippi, Amazon, San Joaquin
Aquifer
Underground layer of rock that contains
water (groundwater)
Aquifer Depletion
Salinization
A build up of salt in the soil as irrigation
water evaporates
Can stunt plant growth and decrease crop
yields
28.8 Carbon Cycle
Carbon moves through the atmosphere and
food webs on its way to and from the ocean,
sediments, and rocks
Sediments and rocks are the main reservoir
Carbon Cycle
Carbon in Atmosphere
Carbon dioxide is added to atmosphere
Aerobic respiration, volcanic action, burning
fossil fuels
Removed by photosynthesis—plant a tree.
28.9 Greenhouse Effect
Greenhouse gases impede the escape of heat
from Earth’s surface
Ex: Carbon dioxide, CFCs, methane, nitrous
oxide
Carbon Dioxide Increase
Carbon dioxide levels fluctuate seasonally
The average level is steadily increasing
Burning of fossil fuels and deforestation are
contributing to the increase
Other Greenhouse Gases
CFCs - synthetic gases used in plastics and
in refrigeration
Methane - produced by termites, bacteria,
and livestock
Nitrous oxide - released by bacteria,
fertilizers, and animal wastes
Greenhouse Gases
Global Warming
Long-term increase in the temperature of
Earth’s lower atmosphere
Effects of Global Warming
As polar ice and glaciers melt, sea levels rise
Effects of hurricanes and storms worsen
Evaporation rates increase causing climate
change (floods and droughts)
28.10 Nitrogen Cycle
Nitrogen important to form amino acids and
nucleotides
Main reservoir is nitrogen gas in the
atmosphere (N2)
N2 can’t be used directly by plants
Nitrogen must first be fixed into useable
forms
Nitrogen Fixation
Volcanic action, lightning, and nitrogenfixing bacteria convert nitrogen gas into
ammonia
Nitrogen Cycle
Human Effects
Humans increase rate of nitrogen loss by
clearing forests and grasslands
Humans increase nitrogen in water and air
by using fertilizers and by burning fossil
fuels
Resulting nitrogen oxides are air pollutants
that cause acid rain.
28.11 Phosphorus Cycle
Phosphorus is part of phospholipids and all
nucleotides
Often a limiting factor in ecosystems
Main reservoir is Earth’s crust; no gaseous
phase
Phosphorus Cycle
Human Effects
In tropical countries, clearing lands for
agriculture may deplete phosphorus-poor
soils
In developed countries, phosphorus runoff is
causing eutrophication (nutrient-enrichment)
of waterways
Chapter 29
29.2 Air pollution in the San Joaquin Valley
POLLUTANT
substance that has accumulated in harmful
or distruptive amounts
Air Pollutants
Carbon oxides
Sulfur oxides
Nitrogen oxides (NOx)
Volatile organic compounds (VOCs)
Particulate Matter (PM)
Ozone
Particulate Matter (PM)
PM2.5 and PM10 based on the particle
diameter (µm)
May be directly emitted as dust or soot
May form in the atmosphere from other
compounds
Problematic in winter
Worst at night or in early mornings
Woodburning stoves and fireplaces
In the winter up to 30% of the PM in the
valley comes from woodburning
Ozone
Not directly emitted
Forms when industrial and vehicular
emissions (especially NOx and VOCs) react
in sunlight
Problematic in the summer
Worst in the afternoon and evening
Carpool, bus, or bike to work/school
Use only electric lawn mowers and tools
Use gas grills instead of briquettes
Postpone use of motorboats or ORVs
Health impacts of PM and Ozone in one
year
460 premature deaths
260 hospital admissions
23,300 asthma attacks
325 new cases of chronic bronchitis
3,230 cases of acute bronchitis in children
17,000+ days of respiratory symptoms in
children
188,400 days of reduced activity in adults
Economic Impacts
Air pollution costs the valley
$3 billion/yr. ($1,000/person/yr.)
In addition to health impacts…
188,000 days of school absences
3,000 lost work days
Jane V. Hall et al. (2006) CSU Fullerton
Valley’s poor air quality
Many factors contribute:
population growth
traffic
industrial sources
agricultural sources
the Valley's topography deters circulation
and results in stagnant air
How bad is it?
www.airnow.gov
www.valleyair.org
Air Quality Index
Which cities have the worst air in CA?
www.epa.gov/air/data/
So what can we do?