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Eco Lecture Final
Terms in this set (140)
Patterns and processes that involve a large number of species.
Community Ecology *
Association of interacting species inhabiting some defined area.
Includes attributes such as number of species,
relative species abundance, and species diversity
Two factors define species diversity:*
- Number of species in the community.
- Relative abundance of species
What will you find if you go into a
community and quantify the abundance
of species within a group of taxonomically or ecologically related organisms? (3)
- Most species are moderately abundant.
- A few species are very abundant.
- A few species are extremely rare.
(Relative abundance of species is one of
the most fundamental aspects of
Preston developed concept of what and was the first to what?
distribution of commonness and rarity
(most species are moderately abundant,
Preston was the first to quantify this
relationship using the lognormal
Preston's Lognormal Concept Suggested what?
That we think of abundance in relative terms, for example, one species is twice as abundant as another.
That we Graph abundance of species in collections as frequency distributions, where the classes of species abundance were intervals of 1-2, 2-4, 4-8, 8-16, etc.
Ecologists have found that the more you
sample a community the more ....
species you will find.
- The common species show up in even
- A great deal of sampling effort is
needed to capture the rare species.
In an equilibrial system, stability is
maintained by what?
The Lotka-Volterra competition models
and predator-prey models assume a
constant physical environment, however most natural environments are subject to various forms of disturbance.
Sousa defined disturbance as what?
- Discrete, punctuated, killing, displacement, or damaging of one or more individuals that directly or
indirectly creates an opportunity for new individuals to be established.
White and Pickett defined disturbance as what?
What are the Two major characteristics?
Any relatively discrete event in time that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the
Frequency and Intensity
(Intermediate Disturbance Hypothesis)
Connell proposed disturbance is what?
What hypothesis did he propose?
a prevalent feature that significantly
influences community diversity.
- Proposed both high and low levels of
disturbance would reduce diversity and that Intermediate levels promote higher diversity.
(Common occurrence according to Connell)
How do Intermediate levels of disturbance promote higher diversity?
Sufficient time between disturbances allowing wide variety of species to colonize, but not a long
enough time frame to allow competitive exclusion.
Low levels of disturbance allow what?
Competition to reduce diversity.
Basic Factors to Consider When Designing
a Sampling Program to Determine Species
Richness Within and Among Communities
Describe sampling effort
• The number of species recorded increases with
higher sampling effort.
• In the example of benthic invertebrates in a
small stream, small sample size was required.
• To verify the presence or absence of
threatened beetle species in a boreal forest
required a sample of over 400 beetle species
and over 100,000 individual beetles.
(Basic Factors to Consider When Designing
a Sampling Program to Determine Species
Richness Within and Among Communities)
describe indicator taxa
Because of the cost and time of making
thorough inventories of species richness,
ecologists have proposed a variety of
taxa as indicators of overall biological
• Even with a restricted taxonomic focus, it
is important to standardize sampling
across study communities
(Basic Factors to Consider When Designing
a Sampling Program to Determine Species
Richness Within and Among Communities)
describe Standardized Sampling
Provides a valid basis for comparing
species richness across communities.
• Several facets of standardized sampling:
- Collecting the same number of samples
from each community.
- Spending the same amount of time
searching the community (in
- Use same sampling methods in each
study area 73 Standardized
Must sample the environment in a way
that takes into account the environmental
requirements and preferences of the
• Standardization of procedures is no
substitute for ecological understanding.
What is a keystone species and what are the characteristics of a keystone species?
Keystone species exert strong effects on their community structure, despite low biomass. (power)
A species with low biomass but large effects
on community structure.
A species whose influence on a community
is disproportionate to its biomass.
Have focused on consumers (predators,
herbivores) as keystone species.
• Other kinds of organisms can act as
keystone species, including mutualists. (grazers as well)
Why are keystone species important?
Paine concluded that if keystone species
reduce the likelihood of competitive
exclusion, their activities would increase
the number of species that could coexist
Feeding activities of a few species have a
controlling influence on community
- Paine reasoned that predators often
keep prey populations below their
- Therefore, the potential for competitive
exclusion would be low.
A summary of feeding interactions within a
community is called what?
A food web
(Paine found that as the number of
species in the intertidal food webs
increased, the proportion of the web
represented by predators also increased. <increased species diversity in short>)
What do the confidence intervals of the means of two samples tell us?
Can use CIs to create a visual comparison of
two populations (can tell a statistical significant difference in biomass between 2 populations.)
Nile Perch (Lates nilotica) exotic fish
predator in Lake Victoria.
- One of the most diverse fish faunas
on earth (400 species)
How did the Nile perch affect Lake Victoria
- Fish fauna dramatically reduced.
Before the introduction of the Nile Perch the food web of Lake Victoria included more than 400 fish species.
After the Nile Perch was introduced the food web and fish catches are dominated by just three fish species.
steelhead trout in California case study, GO!
Power investigated whether California roach
Hesperoleucas symmetricus and steelhead
trout Oncorhynchus mykiss significantly
influence food web structure.
How do predatory fish decrease algal
- Low predator density increased midge
- Increased feeding pressure on algal
- Thus, fish act as Keystone Species.
Ecosystem ecologists study what major areas?
energy, water, and nutrients.
• Fundamental areas of interest:
- Primary production
- Energy flow
- Nutrient cycling
(Ecosystem: A biological community plus
all of the abiotic factors influencing that
What usually limits primary production in a terrestrial environment?
Two variables are most strongly
correlated with variation in terrestrial
Highest rates generally occur under
warm moist conditions.
Where do we find the highest rates of marine primary production?
Highest rates of primary production by
marine phytoplankton are generally
concentrated in areas with higher levels
of nutrient availability.
• Highest rates found along continental
- Nutrient run-off from land.
- Sediment disturbance.
• Open ocean tends to be nutrient poor.
- Vertical mixing main nutrient source.
How do consumers influence rates of primary production in ecosystems?
Influences of physical and chemical
factors of an ecosystem.
Influences of consumers.
Fixation of energy by autotrophs in an ecosystem.
describes the use, movement, and recycling of nutrients in the environment.
At the first trophic level, primary producers (plants, algae, and some bacteria) use solar energy to produce organic plant material through photosynthesis. ... and so on as energy moves through the organisms that consume them including decomposers. what term describes this?
Position in a food web
determined by number of energy
transfers from primary producers to
occupy first level
Occupy the second level
Occupy third level
Occupy fourth level
(Lindeman concluded that the study of
energy transfer within an ecosystem is
fundamental to the ecosystem concept.
- Suggested grouping organisms within
an ecosystem into trophic levels.
- Each feeds on level immediately
We will use the samples of the two
caddisfly populations (biomass from
flooded and unflooded streams in
Chapter 17) to test for significant
differences using what?
• This involves using what?
this is a generic situation to define this term.
- Calculating the statistic, t.
- Comparing the value with a table of
critical values of t.
How do consumers influence rates of primary production in ecosystems?
consumers have significant effects on primary production in some terrestrial ecosystems:
Found grazers can increase primary
- Increased growth rate.
- Compensatory Growth
- Lower respiration rate due to lower
- Reduced self-shading.
- Improved water balance due to
reduced leaf area
name the layers of ecological studies (8)
(ex. how do zebras regulate their water balance?)
,** (individual organisms in an area, what factors control these organisms;What is the relationship between resource availability and birth rate?)
(symbiotic relationships such as birds eating parasites), do lions influence where zebras feed in the landscape?)
(how does disturbance influence the number of mammal species in African grasslands?)
** (how does fire affect nutrient availability in grassland ecosystems?)
(How do vegetated corridors affect the rate of movement by mammals among isolated forest fragments?)
larger scale, (how has geologic history influenced regional diversity within certain groups of organisms?)
(what role does concentration of atmospheric CO2 play in global warming?)
Biome features include what? (5)
define tropical rainforests latitude, temperature variation and precipitation.
Most occur within 10 degrees latitude of equator.
• Little temperature variation between
• Annual rainfall of 2,000 - 4,000 mm (80-
160 inches) relatively evenly distributed.
- Quickly leaches soil nutrients.
Warm and wet year-round.
• Soil organic matter low (Why?)-leeching
• Soils nutrient-poor and acidic.
• Diversity of trees (often 300/ha.).
• Many of the world's foods originated in
here: maize, rice, bananas,
• 25% of prescription drugs derived from
what is found a little further from the equator than a tropical rainforest usually found between 10-25 degrees latitude defined by less rain and more seasonal than a tropical rainforest.
Tropical Dry Forests
Dry season can last last 6-7 months
Soils in this forest are less acidic than in TRF
Height of trees are correlated with average precipitation.
Many birds, mammals, and insects are
Much more severely impacted by man than TRF
They are generally richer in nutrients, but vulnerable to erosion
Tropical Dry Forest
Most __________ occur north and south of tropical dry forests within 10-20 degrees of the equator.
These alternate between wet/dry seasons.
Soils in tropical savannas have ________ water permeability. what does this effect?
Landscape is more two-dimensional with
increasing ____________ to produce livestock.
drought associated with tropical savanna's in the dry season leads to wildfires caused by what? (drier than TDF)
The tropical savanna is the earliest inhabited biome by man.
saturated soils keep trees out.
Lightning (These fires are very important for maintaining the biome.)
What biome's major bands lye at 30 degrees N and 30 degrees S in latitude
-occupy about 20% of earth's land surface.
-Soils extremely low in organic matter.
in a desert biome plant cover ranges from sparse to absent.
Explain animal abundance and biodiversity.
Soils in deserts often contain high concentration of _______ this is from what?
this is the only biome that is ________________ in area due to human activity.
Animal abundance is low but biodiversity may be high
There are strong behavioral adaptions in animals and human intrusion is increasing.
This biome occurs in all continents except Antarctica.
Has a climate that is cool and moist in fall, winter and spring but can be hot and dry in summer.
Mediterranean woodland and shrubland
Mediterranean woodland and shrubland biomes have ____________ soils with moderate fertility.
Trees and shrubs are typically _______________ and are what?
This biome has a long history of human intrusion and is cleared out for agriculture.
In Mediterranean woodland and shrublands there is a ________ biological richness.
Organisms show similar adaptation to those living in ____________.
There is ________ human population densities.
evergreen, fire resistant due to fire regime.
what biome is characterized by middle latitudes and extremely widespread distribution
-This biome has some of the richest soils on earth and are extremely nutrient rich and deep (large human intrusion, most fertile for agriculture)
-thoroughly dominated by herbaceous vegetation and Large roaming ungulates.
-Bison vs. cattle (grazers due to grass being dominant plant).
-the largest biome in North America
Biomass can be as great as in TRF but
diversity is LOWER.
• Less than 1-2% of old growth forests
remain in North America (most in western
Temperate Forrest (old growth)
Temperate Forrest (old growth) soils are _______.
describe the growing seasons and what vegetation dominates these seasons.
Biomass production can be ___________. in temperate forests.
• Many major human population centers.
fertile and rich as well
Long growing seasons dominated by deciduous plants
Short growing seasons dominated by conifers
What biome is confined to the northern hemisphere and covers 29% of the earths land area?
Boreal Forest (Taiga)
what vegetation dominates in taiga?
what is the animal density like?
what is the climate like in a boreal forest?
Relatively high animal density.
• Historically, low levels of human
Winters too long and summers too short to support temperate forest.
precipitation lower than TF, but evaporation is also low due to long winters.
where are much of the nutrients found in a boreal forest?
what does this forest specifically provide a great habitat for?
how are trees pollinated? Is there any fruit?
What issue is going on in boreal forests?
Much of the nutrients are tied up in plant
litter on forest floor.
• Nesting habitat for many migratory birds.
• All trees are wind pollinated with no
Deforestation for lumber
what covers most of the lands north of the Arctic circle?
Climate typically cool and dry with
200 - 600 mm precipitation.
Low decomposition rates.
• Supports substantial numbers of native
• Human intrusion historically low, but
increasing as resources become scarce.
Describe the soils of a tundra.
what limits tree growth?
what plants dominate a tundra then?
what about animal inhabitance?
-Soils accumulate much organic matter as peat and humus
-permafrost (causes solifluction) and low precipitation.
-Plants dominated by grasses, sedges, mosses and lichens.
The woody vegetation is mostly dwarf willows and birches.
-Large mammals include caribou,
reindeer, musk ox, bears, wolves.
Display monthly temps and precipitation values, help determine the productivity of a biome
-Relative position of lines reflects
- Adequate moisture for plant
growth when precipitation above
what primarily characterizes a biome?
what 2 things shape a biome?
vegetation and climate
temperature and precipitation
____________________, describes the continuous movement of water on, above, and below the surface of the Earth. Water is always changing states between liquid, vapor, and ice, with these processes happening in the blink of an eye and over millions of years.
The saturation water vapor density needs what primarily to quantify its value? what does this tell us?
(directly proportional the warmer the air the more water vapor it can hold.)
-The quantity of water vapor
air can potentially hold
(static distribution of earths water)
around what percent of the earth is covered by water?
what do oceans make up of that?
polar ice caps and glaciers contain _____
freshwater in lakes streams and ground water make up
oceans contain 97%
less than 1%
How would you assess the health of an aquatic system? (3)
- Measure pollutants
- Monitor physical and chemical
conditions required by aquatic
organisms (measure conditions that aquatic organisms require such as oxygen concentration for example)
- Fish community is often studied to
assess health of aquatic systems
____________: Small scale weather
variation, usually measured over shorter
(ex. how can amphibians survive in the desert? they seek out one of these)
(offers contrasting environments for vegetation and other organic entities)
______________: Large scale weather
How do organisms respond to
substantial variations in environmental
temperatures given their own fairly
narrow thermal requirements?
Balancing Heat Gain Against Heat Loss utilizing temperature regulation though heat exchange pathways.
Balancing Heat Gain Against Heat Loss
HS = Hm +or- Hcd +or- Hcv +or- Hr - He
what do each of the variables represent?
(need to know? beats me, overgeneralized study guide provided for the creation of this)
HS = Total heat stored in an organism.
-Hm = Gained via metabolism.
- Hcd = Gained / lost via conduction.
- Hcv = Gained / lost via convection.
- Hr = Gained / lost via electromag.radiation.
- He = Lost via evaporation.
Desert Plants Accomplish heat storage reduction by:
• Have evolved ______ leaves.
• Changing the __________ of leaves and
• _________ surfaces.
- Many are covered with a coating of
Temperature Regulation by Plants
:Arctic and Alpine Plants:
- Two main options to stay warm: what are they?
- Increase radiative heating (Hr).
- Decrease Convective Cooling (Hcv).
Temperature Regulation by
-(true or false) Some species can adjust for radiative heating by varying intensity of
pigmentation during development.
- ____________ often help plants in dry
environments extract water from deep
within the soil profile.
-- Park found supportive evidence via
studies conducted on common
Japanese grasses, Digitaria
adscendens and Eleusine indica.
what is special about the kangaroo rat ?
what about the water budget of some beetles as mentioned in the text?
It can go without drinking (no Wd) and obtain all the water it needs from its food (Wf).
They gather water from fog condensed on their abdomen and can drink water from this around their mouth.
What is unique about camels approach to dealing with water loss?
- Can withstand water loss up to 20%.
- Face into sun to reduce exposure.
- Thick hair: Increased body
temperature lowers heat gradient.
-can drink 1/3 of its body weight in water and store it (it does not occur in the hump but stores it in its tissues)
What is unique about saguaro cactus approach to dealing with water loss?
-Trunk / arms act as water storage
- Dense network of shallow roots.
- Reduces evaporative loss
(saguaro closes stomata during the day).
Overview of water conservation techniques utilized by plants and animals.
Many terrestrial organisms equipped with
waterproof __________ _________.
• Concentrated ___________
• Condensing water vapor in breath.
-_____________ modifications to avoid stress
• ________ leaves in response to drought.
• Thick leaves.
• Few ____________.
• Periodic dormancy.
urine / feces.
How do Scorpions and Cicadas differ in their approach to managing water loss?
- Slow down, conserve, and stay out of
- Low metabolic rates.
Cicadas (Diceroprocta apache)
- Active on hottest days.
- Perch on branch tips (cooler
- Reduce abdomen temp by feeding on
xylem fluid of pinyon pine trees.
What primarily determines the availability of water in both terrestrial and aquatic environments?
The tendency or water to move down concentration gradients, and the magnitude of those gradients, determine whether an organism tends to lose or gain water from its environment. (solute vs. solvent balance, or salt/water ratio)
-Sharks, skates, rays - Elevate blood solute concentrations hyperosmotic to seawater. meaning what?
- Marine bony fish are strongly
hypoosmotic, thus need to
-They Slowly gain water osmotically.
-Drink seawater for salt influx.
______________ use inorganic sources of
carbon and energy.
______________ use CO2 as carbon source, and sunlight as energy.
_____________Use inorganic molecules as source of carbon and energy.
_______________ use organic molecules as sources of carbon and energy.
Heterotrophs (know combinations)
Photon Flux and Photosynthetic Response Curves
- Rate of photosynthesis increases ___________
with photon flux density at low light
-rises more slowly with
intermediate light intensities, and tends
to __________ at high light intensities.
(Response curves for different species
generally level off at different maximum
Limits on potential rate of energy intake
by plants have been demonstrated by
studying response of
photosynthetic rate to photon flux density.
• Assumes if energy supplies are limited,
organisms cannot simultaneously
maximize all life functions.
- Must compromise between competing
demands for resources through what?
principal of allocation
What defines this information?
-All organisms have access to limited energy.
-Organisms allocate limited energy to a certain function which then reduces the amount for other functions.
The Principle of Allocation
(This trade-off in energy allocation will
differ among environments with
functions that include growth,
reproduction, and defense against
consequences of the principle of allocation are what?
organisms are adapted to the environment that they have a long evolutionary history in, have lower fitness in another environment
What are the three characteristics of Eusociality?
1. Individuals of more than one
generation living together.
2. Cooperative care of young.
3. Division of individuals into
exhibit co-operation in reproduction and division of labor, overlap of generations
Convergence in social organization
light on forces responsible for the
evolution of ______________.
• Kin selection may play a role.
• In ants, haplodiploidy system exists:
• Males are haploid.
• Females workers (diploid) would be more
closely related to each other than they
would be to their own offspring.
Evolution of sociality is generally
accompanied by what three actions?
- Cooperative feeding
- Defense of the social group.
- Restricted reproductive opportunities.
(• Cooperation generally involves
exchanges of resources or other forms of
examples being wasps
potential for evolutionary change in natural populations is very great.
It can give us a measuring stick by witch to measure evolutionary change (which is the rule rater than the exception)
-Large population size
- Equitable fitness between all genotypes
This is defines what?
The Hardy Weinberg system
____________ leads to changes in phenotypes by favoring an extreme phenotype over other phenotypes in the population
(most phenotypes have lower reproduction and survival compared to exceptional phenotypes)
(population average changes in a particular direction over time)
(Because degree of competition is
assumed to depend upon degree of niche overlap, interspecific competition has been predicted to lead to this)
____________ Creates bimodal distribution by favoring two or more extreme phenotypes over the average phenotype in a population.
(average phenotypes have lower reproduction and survival compared to extremes in the population)
(over time phenotypes become less common and the population becomes more phenotypically diverse.)
Under ______________ extreme phenotypes in a population have lower rates of reduction and survival (acts against extreme phenotypes and favors average)
acts to impede changes in a population by acting against extreme phenotypes and favoring average phenotypes.
(as a consequence, the average phenotype remains the most common from one generation to the next.)
Frankham and Ralls point out _____________ may be a contributor to higher extinction rates in small populations by reducing genetic variability.
(So quit going to family reunions to find dates)
(increase homozygosity, less genetic variability; a cycle that feeds on itself, mixing of genetic material from different populations increases genetic variability and survival, increases chance that harmful recessive genes will be expressed in the phenotype)
(1) Define random change in the gene pool.
(2) How do random changes happen in the gene pool? (3) what is this called?
--(1)Random processes that can change gene frequencies in populations, especially in SMALL POPULATIONS (much more susceptible)--. The major concern of --(2) habitat fragmentation is reducing habitat availability to the point where random change in the gene pool-- called --(3) genetic drift-- will reduce genetic diversity within natural populations.
Picea chihuahuana is now restricted to
peaks of Sierra Madre Occidental in N.
- Ledig et.al. examined populations to
determine if the species has lost
genetic diversity as a consequence of
reduced population size
- Found significant positive correlation
between population size and genetic
diversity of study populations.
What is this evidence of?
(Distribution of Individuals on Small Scales)
(1)______________: Equal chance of being anywhere.
Uniform distribution of resources.
(2)____________: Uniformly spaced.
- Exclusive use of areas.
- Individuals avoid one another.
(3) _____________: Unequal chance of being
- Mutual attraction between individuals.
-Patchy resource distribution.
(Clumped patterns occur in species with
(Competition among clumped desert shrub plants
produces higher mortality.
Eventually creating regular distributions.)
what does the Lincoln-Peterson Index involve?
(4 main steps here)
1. Involves marking or tagging some
known number of individuals in the
2. Releasing the marked individuals so
they will mix with the remainder of the
3. Then sampling the population at
some later time.
4. The ratio of marked to unmarked
individuals in the sample gives an
estimate of population size.
What are assumptions made about the Lincoln-Peterson Index? (4)
- All individuals in the population have
an equal probability of being captured.
- The population is not increased by
births or immigration between marking
- Marked and unmarked individuals die
and emigrate at the same rate.
- No marks are lost.
In Generating data for the Lincoln-Peterson Index..
M/N = m/n, therefore, N = Mn/m
-this allows you to obtain the size of the population (N), what do the other variables stand for?
(This is probably TMI)
M = the number of individuals marked
N = the actual size of the study
m = the number of marked individuals
in a sample of the population.
n = the total number of individuals in
(Offspring Number Versus Size)
_______________________ states that If organisms use energy for one function such as growth, the amount of energy available for other functions is reduced.
Principal of allocation.
(Leads to trade-offs between functions
such as number and size of offspring.
- *Those that produce larger offspring
are constrained to produce fewer*
Winemiller and Rose proposed new
classification scheme based on age of
reproductive maturity (α), juvenile
survivorship (lx) and fecundity (mx).
________________: low lx
- low mx
- early α
________________: high lx
- low mx
- late α
________________: low lx
- high mx
- late α
_________________ is the number of
individuals of a population the
environment can support.
(the leveling off point of the sigmoid)
-A Finite amount of resources can only
support a finite number of individuals.
Carrying capacity (K)
In an Unlimited Environment,
Population Growth Can Occur at Two
Possible Rates, what are they?
(many plants exhibit this)
When generations do not overlap, growth can be modeled
Growth in any population with __________________ can be modeled as
(Successive generations differ in size by a
Continuous population growth in an
unlimited environment can be modeled
how if generations overlap?
(For example, the Whooping crane after it became protected.)
Environmental limitation is incorporated
into this model of population growth.
Example: rate of growth of collared dove
populations began to slow by 1970.
Logistic Growth model
As resources are depleted, population
growth rate slows and eventually stops.
what growth model is this?
what graphically represents this?
Logistic Population Growth
Sigmoid (S-shaped) population growth curve.
(an example of this is found in a yeast population)
-The Barnacle, Balanus
What characterizes r and k strategies?
Intrinsic Rate of Increase:
-Highest in ____ selected species.
• Competitive Ability:
-Highest in ____ selected species.
-____: Numerous individuals rapidly
produced. (single, semelparity)
-____: Fewer larger individuals slowly
produced. (repeated, iteroparity)
____ = Rapid
____ = Slow
• Body Size:
_____ = Large (few)
_____ = Small (many
(table 12.1 slide 35 chapter 12)
Reproduction under r-selection will tend
a single reproductive event in
which many small offspring are produced (Semelparity).
K selection should favor __________ type of reproduction
repeated ,fewer larger offspring
(Spaces out reproduction over several
reproductive periods in an organism's
Competition with members of own
Competition between individuals of two
species - reduces fitness of both
Direct aggressive interaction between
Summarizes environmental factors that influence growth, survival, and reproduction of a species.
______________________ defines the physical (abiotic) conditions under which a species might live, in the absence of interactions with other species.
_______________ refers to the more restricted conditions under which a species actually lives in nature as a result of those interactions (abiotic and biotic)
Give some major biotic factors that can influence this niche. (4
______________________________: States that
Two species with identical niches
cannot coexist indefinitely.
(can have very similar niches however)
why in the sam hill is this?
Gause: Principle of Competitive
- One will be a better competitor and
thus have higher fitness and
eventually exclude the other.
_______________ are Interaction between populations that enhances fitness of one individual while reducing fitness of the exploited individual.
• 10 million species in biosphere.
• _____________ interactions between species is far greater.
- Every species is food for a number of
other species (including parasites and
• One estimate of this type of interaction for Lake Okeechobee, Florida:
- 500 species in the lake.
- 25,000 exploitative interactions.
what examples of parasite/host exploitative interaction were spoken of in class? (3)
what about the herbaceous exploitation utilized in Australia? (1)
(3)Spiny-Headed Worm (Acanthocephalan) changes behavior of amphipod in ways that make it more likely that infected amphipods will be eaten by a suitable
(2)The pill bug serves as an intermediate
host for Plagiorhynchus, which
completes its life cycle in the starling.
-Plagiorhynchus alters the behavior of the
(3) a protozoan parasite (Adelina tribolii)
influences competition in flour beetles
- Adelina lives as an intercellular
(4) Moth, Cactoblastis cactorum,
found to be effective predator to the cactus in australia
(It is herbivorous and was released to destroy over abundance of this cactus)
What substantially affects the abundance and structure of prey and host populations via exploitation?
Predators (herbaceous or carnivorous) , parasites, and pathogens (disease)
(greater numbers of these = higher exploitation)
occurs when a species is dependent on a mutualistic relationship.
occurs when a species can live without its mutualistic partner.
Interactions between individuals of different species that benefit both partners.
What is an example of obligate mutualism in the ocean?
- Crustacean mutualists substantially
improved chances coral will avoid
attack by sea stars.
-Also found crab activity promotes coral
health and integrity.
Pocillopora coral increases production
of fat bodies in the presence of crabs.
Digestive tract of crabs inhabiting
corals contained large quantities of
17 species of crabs and one species of
shrimp are found only on corals.
• This is apparently obligate mutualism.
• Corals provide these crustaceans with
food and shelter.
• Crabs and pistol shrimp attack sea stars
by pinching and clipping their spines and
What is an example of a terrestrial obligate mutualism?
Ants and bullhorn acacias mutualism.
Acacias form obligate mutualisms with
ant species (Pseudomyrmex) in tropics
and subtropics of southern Mexico
through northern S. America.
• In exchange for food and shelter, ants
protect acacias from attack by herbivores
and competition from other plants.
• Once an ant colony has 50-150 workers
(takes 9 months), they patrol the acacia
plant day and night.
Herbivores attempting to forage on
acacia plants occupied by acacia ants are
met by a large number of fast, agile,
• Ant Benefits:
- Thorns provide living space.
- Foliar nectaries provide sugar.
- Beltian bodies are a source of oils and
Human mutualistic relationships include what example of facultative mutualism in Africa?
Humans have gathered honey in Africa
for at least 20,000 years.
• The association with the honeyguide is
as old as honey gathering.
The Honeyguide is in the Order Piciformes.
- Most feed on beeswax and insects.
- 17 species: only 1 species guides
humans and other mammals to bees'
Found throughout sub-Saharan Africa.
• Occurs in tropical savanna and tropical
• It is a brood-parasite.
- Young honeyguides have bill hooks.
The mutualism with mammals is
- Boran people of Kenya follow
honeyguides and have developed a
penetrating whistle to attract them.
- With the aid of a honeyguide, It takes
on average 3.2 hours to find a bees'
**96% of bees' nests found would have
been inaccessible to the birds without
• The greater honeyguides attract the
attention of a human by flying close and
Explain the mutualism between Coral and Zooxanthellae.
Zooxzanthellae live within coral
- Receive nutrient from coral. In return,
coral receives organic compounds
synthesized by zooxanthellae during
(in depth piece...)
Corals induce release of organic
compounds with "signal compounds"
that alter permeability of zooxanthellae
Corals also control rate of zooxanthellae
population growth and density by
influencing organic matter secretion.
• Main zooxanthellae benefit appears to be
access to higher nutrient levels,
especially N and P.
- Uptakes ammonium excreted by coral.
Allen and Allen studied water relations of
grass Agropyron smithii.
- Plants with mycorrhizae maintained
higher leaf water potentials.
- Improves the ability of the plant to
extract soil water.
(Plants with greater access to
phosphorus may develop roots that
are more efficient at extracting and
The 2 types of mycorrhizae discussed are:
-Arbuscular mycorrhizal fungi (AMF)
What mutualistic benefit do each contribute to plants?
AMF:- Produces arbuscules - site of
exchange between plants and fungi,
hyphae - fungal filaments, and
vesicles - energy storage organs.
ECM- Forms mantle around roots being
important in increasing plant access
to phosphorus and other immobile
In simple terms...
they have an association between plant roots and
- Provides plants with greater access to
- Fungi feed off of root exudates of
In an Index of Biological Integrity (Often
Applied to Fish Communities) "IBI"
• Three categories are used for rating a stream
or river what are they?
1. Number of species and species
2. Trophic composition: omnivores,
insectivores, and piscivores.
3. Fish abundance and condition.
what variables are the IBI numbers based on?
Ss+Sf+Sa+Sh = IBI
Ss = number and kinds of species
Sf =Feeding biology of species
Sa= fish abundance
Sh = fish health
In an IBI
A numerical score is assigned to each of
seven variables of the fish community (1=
________ conditions, 3 = ______ conditions, and
5 = ______ conditions).
The scores are then summed for each
locality to determine the IBI
Heterotrophs - Using Organic Molecules
• Three Feeding Methods of Heterotrophs: what are they and what do they feed on?
-Herbivores: Feed on plants.
-Carnivores: Feed on animal flesh.
-Detritivores: Feed on non-living
-Differences in reproductive rates
among individuals as a result of
differences in mating success
--Individuals of one sex compete among themselves for mates.
---Individuals of one sex consistently choose mates among members of opposite sex based on a particular trait.
--Intrasexual Selection (males competing for territories, the ones with greater fitness will dominate these)*
Intersexual Selection *
A _______________ is a group of individuals of a single species inhabiting a specific area.
-Characterized by the number of
individuals and their __________.
-Additional characteristics of a
population include age distributions,
growth rates, _______________, and
Evolution toward niche divergence in the
face of competition is called what?
(Character Displacement in Galapagos Finches)
• The medium ground finch and the small
ground finch are allopatric on 3 islands
and are sympatric on one island.
where do they have smaller beak sizes?
where do the beak sized not overlap?
Where the two species are allopatric, they
have similar beak sizes.
where they are sympatric, the
sizes of their beaks do not overlap.
(EXAMPLE OF CHARACTER DISPLACEMENT)
To persist in the face of exploitation,
hosts and prey need.
Many forms of spatial refuge are
obvious what are some examples?
Some spatial refuges differ in subtle
ways from other areas. Give an example of why?
Burrows, trees, air, water, land.
One reason for the persistence of
cactus in Australia: small isolated
populations of cactus are difficult for
Cactoblastis to find.
Living in a ______________ provides a
Peckarsky observed mayflies (Family
Ephenerellidae) making themselves what?
look larger in the face of foraging
stoneflies. (also a form of refuge due to less profitability by predator and energy expenditure according to the optimal foraging theory)
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