Ecology


Topics:

Ecology (10%)

  1. Population dynamics
  2. Communities and ecosystems
  3. Global issues

JFMcL. The most difficult cycle to remember is the nitrogen cycle. The most important point is that bacteria are essential to the functioning of this cycle. Nitrogen fixing bacteria in the root nodules of legumes or in the soil take the nitrogen out of the air (abiotic reservoir), and convert it into nitrates which can then be used by the plants. Animals eat the plants and get their nitrogen grom the plants or other animals. The nitrogeneous waste products are broken down by ammonifying bacteria and nitrifying bacteria and the dead animals are also decomposed by bacteria of decay. Finally nitrogen is returned to the air by denitrifying bacteria. Below is a diagram of the process:
Nitrogen cycle
Nitrogen cycle

http://www.bing.com/images/search?q=nitrogen+cycle+diagram&view=detail&id=FC1204CC71EB400D92791167A738D239BEB2ABB0&first=0&FORM=IDFRIR

RMG
external image 52-03-IdealizedSurvCurve-AL.gif
Demography is the study of vital statistics of a population (especially birth and death rates). Survivorship curve type one shows low death rates during early and midlife with a sharp increase in death rate in older age groups. Survivorship curve type two shows a constant death rate over the organism's life span. Survivorship curve type three shows high early death rates then a flat rate for the few surviving older age groups.

KGT
I had trouble keeping r-selection and K-selection straight. K-selection deals with factors that are sensitive to population density and carrying capacity. Logistic growth is associated with K-selection. r-selection deals with factors that maximize reproductive success, so exponential growth is associated with r-selection.

r-selection
Unstable environment, density independent
K-selection
Stable environment, density dependent interactions
small size of organism
large size of organism
energy used to make each individual is low
energy used to make each individual is high
many offspring are produced
few offspring are produced
early maturity
late maturity, often after a prolonged period of parental care
short life expectancy
long life expectancy
each individual reproduces only once
individuals can reproduce more than once in their lifetime
type III survivorship pattern
in which most of the individuals die within a short time
but a few live much longer
type I or II survivorship pattern
in which most individuals live to near the maximum life span
external image expgrowth.gif
JFM. Great choice of topic! This is one that is frequently confused!

SRF
I struggled with biomes on the test, and this chart helped me organize my thoughts.


biomes.PNG
SMM
I find it easier to remember the differences between primary and secondary succession if I can visualize them.
external image succession.jpg
external image 95198-036-2619E3FA.jpg

EGR
Continuing studying ecology, I have found that I still become slightly confused in the differences between density-dependent and density-independent factors.
  • Density-dependent - occurs when population growth is affected by the number of individuals living in an area, such as predators or organisms from the same species
  • Density-independent - a factor affecting population sizes that is not correlated to population sizes or number of organisms, such as natural disasters or seasonal temperature changes (earthquake, monsoon, tornado, forest fire)

density-indep.jpg
Density-independent example, due to seasonal temperature change
predator_prey.jpg
Density-dependent example where predation causes prey numbers to decline, then prey rebounds due to fewer predators


http://www.biog1105-1106.org/demos/106/unit09/18.density-independent.html
http://www.google.com/imgres?um=1&hl=en&sa=X&biw=1366&bih=577&tbm=isch&tbnid=5P5AD7z4lJ-NlM:&imgrefurl=http://www.sci.sdsu.edu/classes/bio100/Lectures/Lect21/lect21.html&docid=a03WLD5_KxSpCM&imgurl=http://www.sci.sdsu.edu/classes/bio100/Lectures/Lect21/Image296.gif&w=640&h=480&ei=qMepT_jnDqfw0gH86tG6BQ&zoom=1&iact=rc&dur=134&sig=110858532070695680912&page=1&tbnh=167&tbnw=223&start=0&ndsp=10&ved=1t:429,r:5,s:0,i:124&tx=177&ty=79


VBG
I couldn't wrap my mind around primary productivity. I found a good explanation, and a good example to help.
Primary Productivity
The flow of energy through any ecosystem starts with the fixation of sunlight by plants and other autotrophic organisms. In this way the plant accumulates energy and this energy is called primary production. The rate at which this energy accumulates is called primary productivity. The total energy accumulated is gross primary production, however, since plants use some of this energy themselves, it is not all available for the food web. The difference between what is accumulated and what is available for the food web is called net primary production expressed in
kilocalories or grams m-2 y-1 or kcal or g/m2/y. This is measured by sequentially measuring growth of the biomass over time by marking the plants somehow, or measuring a total at the end of the growing season. Alternatively you can measure oxygen production or CO2 consumption both of which equal grams C produced. (experiment possiblities!)
In general, swamps and marshes have the highest primary production of all the world's ecosystems. Primary production of all wetland types varies from 600-2000 gC/m2/y.
To review a little:
In general, the "openness" of a wetland to hydrological fluxes is probably one of the most important determinants of primary productivity. So wetlands that are stagnant are less productive than those that flow or are open to flooding rivers. This makes sense because a flow-through system constantly gets more nutrients. This isn't 100% though because wetlands get most of their nutrients from recycling rather than from the outside. This is what allows them all to be fairly productive.
Salt Marshes:
These tend to be the most productive ecosystems in the world. Estimates of the southern coastal plain of the U.S. have topped 8000 gC/m2/y through the combined efforts of marsh grass, mud algae, and phytoplankton in the tidal creeks. The southern marshes do better than the northern ones partly because of the greater influx of solar energy and longer growing season, and partly because of the nutrient rich sediments carried by rivers in that region.
Low or intertidal marshes are more productive than high marshes because of the increased exposure to tidal flow.
Belowground production is high. Under unfavorable soil conditions, plants seem to put more energy into root production. (experiment possibility!)
Generally, plant production depends on light, water, nutrients, and toxins. If you look at a salt marsh it has full sun, limitless water, and the sedimentary soil is generally rich in nutrients so you'd expect uniformly high production. That doesn't happen:
1. Productivity declines northward as the growing season shortens.
2. Water looks plentiful but because it's salty the plants tend to lose water and so must expend energy in order to take it up. It's been shown that plant growth is progressively inhibited by salt (experiment possibility!)
3. The less oxygen the soil contains, the worse the plants do even if they're adapted to survive


JM:
Gross primary production (GPP) is the total energy (or nutrients) assimilated by an ecological unit (such as an organism, a population, or an entire community).

Net primary production:
is the production of organic compounds from atmospheric or aquatic carbon dioxide, principally through the process of photosynthesis, with chemosynthesis being much less important. All life on earth is directly or indirectly reliant on primary production. The organisms responsible for primary production are known as primary producers or autotrophs, and form the base of the food chain. In terrestrial ecoregions, these are mainly plants, while in aquatic ecoregions algae are primarily responsible. Primary production is distinguished as either net or gross, the former accounting for losses to processes such as cellular respiration, the latter not.

EGR
As I have been reviewing the review book more, I noticed there is quite a bit of information about aquatic biomes.

Important facts to note from our book/review book:
1. Aquatic biomes make up over 75% of Earth's surface
2. The biomes are either freshwater, or marine biomes (meaning the ocean, water with a high salinity)

Here is an image of the general freshwater biome:

littoral-zonelimnetic-zone.jpg

The important parts of this biome are the littoral and limnetic zones. The littoral zone has decent lighting from the sun, and can provide space for plants to grow and thrive. The limnetic zone is not very well-lit, so does not provide a home to much plant life. The limnetic zone can provide home to phytoplankton, though, as the surface of the limnetic zone is well-lit.
Freshwater lakes can be either oligotrophic or eutrophic. Oligotrophic lakes are very deep, with a lot of oxygen, but little nutrients, so therefore few phytoplankton. Eutrophic lakes on the other hand are fairly shallow, have a lot of nutrients, and fewer oxygen, but can support high concentrations of phytoplankton.

Here is an image of a general marine biome:
marinezonation.jpg
The key parts of this diagram for the marine biome are the intertidal zone, the neritic zone, and the oceanic zone. The intertidal zone is where the land meets water, and undergoes submersion twice daily. The neritic zone is the shallow water over the continental shelves. The pelagic zone depicted in the image in the zone of vast blue ocean, past the continental shelves. The benthic zone is the layer containing sand and other sediments, at the bottom of the biome. The photic zone is the region where plants and other autotrophs can thrive, but the aphotic zone does
Websites:
http://www.bio.miami.edu/ecosummer/lectures/lec_biomes.html
http://www.lakeaccess.org/ecology/lakeecologyprim9.html
CCAI know that the relationships between organisms is one of the most important concepts in ecology so this is a summary of the roles of competitive exclusion and interspecific competition in an ecosystem.A community is a group of populations of different species living close enough to interact.Interspecific competitions for resources occur when resources are in short supply. Competition is a -/- interaction.

  1. the competitive exclusion principal states that when two species are vying for a resource, eventually the one with the slight reproductive advantage will eliminate the other.
  2. An organism's ecological niche is all the biotic and abiotic resources that a species uses in it environment. A species fundamental niche, the niche potentially occupied by the species, if often different from the realized niche, the portion of the fundamental niche the species actually occupies.
Predation is a +/- interaction between two species in which one species ( the predator) eats the other species ( the prey). Defenses include:

  • Cryptic coloration- animal is camouflaged by its coloring
  • aposemantic or warning coloration is when a poisonous animal is brightly colored as warning to other animals.
  • Batesian mimicry- harmless species has evolved to mimic the coloration of an unpalatable or harmful species. In Mullerian mimicry, two bad tasting species resemble each other, so predators will learn to avoid them equally.
  • Herbivory- +/- interaction in which an herbivore eats part of a plant or alga. It is advantageous for the animal to be able to distinguish toxic from nontoxic plants.
* A plant's main protective devices are chemical toxins, spines, and thorns.
Taken from the review book, chapter 54!

ABMJust a general review taken from the review book ch. 51Learning- The modifcation of behavior based on specific experiencesImprinting- Combination of learned and innate components that are all limited to a sensitive period in an organism's life and is generally irreversible. Something that should come to mind is Konrad Lorenz's demonstration with newborn greylag geeseHabituation- A loss of responsiveness to stimuli that convey little or no informationCognitive Map- An internal representation of spatial relationships among objects in an animal's surroundingsAssociative Learning- The ability of many animals to associate one feature of their environment with another featureClassical Conditioning- Learning to associate certain stimuli with reward or punishmentOperant Conditioning- An animal learns to associate one of its behaviors with a reward or punishmentCognition- The ability of an animal's nervous system to perceive, store, process, and use information from sensory receptors
KGTAquatic biomes make up the largest part of the biosphere. The different zones are important to remember. This is taken from the review book.1. All aquatic biomes display vertical stratification:
  • The photic zone, in which there is enough light for photosynthesis to occur, and an aphotic zone, where very little light penetrates.
  • The benthic zone is located at the bottom of the biome, where it is made up of sand , inorganic matter, and organic sediments.
  • Thermoclines are narrow layers of fast temperature change that separate a warm upper layer of water and cold deeper waters.
2. The two types of freshwater biomes are standing bodies of water like lakes and moving bodies of waters like rivers.
  • In lakes, communities are distributed according to the water's depth. The littoral zone (well-lit shallow waters near the shore) contains rooted and floating aquatic plants, whereas the limnetic zone (well-lit open surface waters farther from the shore) is occupied by phytoplankton.
3. Marine biomes include:
  • The intertidal zone, where land meets water, is periodically submerged and exposed to twice-daily tides.
  • The neritic zone, beyond the intertidal zone, is the shallow water over the continental shelves.
  • The pelagic biome s a vast realm of open blue water found past the continental shelves.

KGTAlthough it isn't that complicated, it is important to remember the different patterns of dispersion. Here's a helpful image to refresh your memory.
external image dispersion.jpg

http://www.harding.edu/plummer/biostats/lectures/descriptivestats.pdf

ABMSomething that confused me was what exactly a keystone species is.
  • The definition states that they exert control on community structure by their important ecological niches.
This definition really didn't help me so I was able to find an example of a keystone species
  • The sea otter is a very good example of a keystone species because it is one of a small group of animals that eats sea anemones. Sea anemones eat the kelp which provide many organisms with a habitat. When sea otter populations decrease, anenome populations increase which destroys the kelp forests, and leads to the decline of species whose habitat is the kelp forest. When sea otter populations are strong, every other species should be doing well.

RP. One topic we talked about briefly when reviewing organism niches is biological amplification. The idea is that as you go higher up in trophic levels, the concentration of toxins such as DDT and PCB increases. This is because organisms higher up in the food chain are consuming greater amounts of these toxins, because it passes through the levels. To put it into perspective, here's a picture of what I'm talking about.
http://sparkleberrysprings.com/v-web/b2/images/t/trophic3b.png
It's dangerous in general to have these substances in the environment, but it can be especially bad for these organisms.

VBGIt is important to understand Community Ecology. I personally had a hard time with interspecific competitions.Taken from review book.Interspecific competitions for resources occur when resources are in short supply. Competition is a -/- interaction between the species involved. Central to the idea of competition and community structure are these two concepts:1. The competitive exclusion principle states that when two species are vying for a resource, eventually one with the slight reproductive advantage will eliminate the other.2. An organism's ecological niche is the sum total of biotic and abiotic resources that the species uses in its environment. a species' fundamental niche, the niche potentially occupied by the species, is often different from the realized niche, the portion of the fundamental niche the species usually occupies.
TWKI was looking over the Ecology test, and I did not understand what the capture-recapture method was.This website has a lab that shows how the process works, however the description below helped me to understand what the process was and what assumptions must be made about the process.
http://www.neiu.edu/~jkasmer/Biol380/Labs/mark&.htm


The Mark and Recapture Technique

The mark and recapture method involves marking a number of individuals in a natural population, returning them to that population, and subsequently recapturing some of them as a basis for estimating the size of the population at the time of marking and release. This procedure was first used by C.J.G. Petersen in studies of marine fishes and F.C. Lincoln in studies of waterfowl populations, and is often referred to as the Lincoln Index or the Petersen Index. It is based on the principle that if a proportion of the population was marked in some way, returned to the original population and then, after complete mixing, a second sample was taken, the proportion of marked individuals in the second sample would be the same as was marked initially in the total population. That is,
R (marked recaptures) / C (total in second sample) = M (marked initially) / N (total pop. size)
The accuracy of this method rests on a number of assumptions, including the following:
  • 1). During the interval between the preliminary marking period and the subsequent recapture period, nothing has happened to upset the proportions of marked to unmarked animals (that is, no new individuals were born or immigrated into the population, and none died or emigrated).
  • 2). The chances for each individual in the population to be caught are equal and constant for both the initial marking period and the recapture period. That is, marked individuals must not become either easier or more difficult to catch.
  • 3). Sufficient time must be allowed between the initial marking period and the recapture period for all marked individuals to be randomly dispersed throughout the population (so that assumption 2 above holds). However, the time period must not be so long that assumption 1 breaks down.
  • 4). Animals are not affected by their marks (i.e., their survival, catchability, ability to migrate, reproductive ability in the time interval are all unaffected by the marks).
  • 5). Animals do not lose their marks.
ELB
I found this study guide that does a nice job of explaining trophic levels and changes in biomass. There are a few images that provide a good view of how the energy flows in an ecosystem.


http://www.marietta.edu/~mcshaffd/lead/trophic.pdf


SALEven though it's not difficult to memorize, it is important to remember the different types of symbiosis. Heres a visual to help you remember.
external image tumblr_lfzyhmuEhr1qaw7ij.png

JJS Here are some examples of symbiotic relationships. Applying terms to real life examples is a great way of remembering and understanding their definitions.

http://www.cosmosmagazine.com/news/3929/the-best-examples-symbiosis-nature


SALMany people confuse the difference between a food chain and a food web. A food chain consists of one organism from each trophic level. A food web consists of multiple good chains. Here are diagrams of each
external image samplefoodchains.GIF
external image foodweb.gif
http://www.cals.ncsu.edu/course/ent425/tutorial/trophic.html
http://www.enchantedlearning.com/subjects/foodchain/

SALI never really understood the carbon cycle. This website had a simple good summary and diagramhttp://eo.ucar.edu/kids/green/cycles6.htmexternal image carboncycle_sm.jpg

The Carbon Cycle

All living things are made of carbon. Carbon is also a part of the ocean, air, and even rocks. Because the Earth is a dynamic place, carbon does not stay still. It is on the move!

In the atmosphere, carbon is attached to some oxygen in a gas called carbon dioxide.

Plants use carbon dioxide and sunlight to make their own food and grow. The carbon becomes part of the plant. Plants that die and are buried may turn into fossil fuels made of carbon like coal and oil over millions of years. When humans burn fossil fuels, most of the carbon quickly enters the atmosphere as carbon dioxide.

Carbon dioxide is a greenhouse gas and traps heat in the atmosphere. Without it and other greenhouse gases, Earth would be a frozen world. But humans have burned so much fuel that there is about 30% more carbon dioxide in the air today than there was about 150 years ago, and Earth is becoming a warmer place. In fact, ice cores show us that there is now more carbon dioxide in the atmosphere than there has been in the last 420,000 years.



WJH
One topic I felt like I needed to review was succession.
Ecological succession refers to the transition of species in a certain area over ecological time, or sequence of community changes after a disturbance.
There are two types:
1. Primary- plants & animals gradually invade a region that was virtually lifeless where soil has not yet formed
  • Initially, only autotrophic prokaryotes may be present.
  • Next, mosses and lichens colonize and cause the development of soil.
  • Once soil is present, grasses, shrubs, and trees sprout from seeds blown or carried in from nearby areas.
Example- newly formed volcanic island
Extreme natural disasters can cause an area to become available for primary succession such as intense wildfires, lava flow, or glaciation
2. Secondary- existing community has been cleared by a disturbance that leaves the soil intact
  • Herbaceous species grow first, from wind-blown or animal-borne seeds.
  • Woody shrubs replace the herbaceous species, and they in turn are replaced by forest trees.
Example- abondoned farms
The relative endpoint for succession is when a community becomes a climax community- very little of extraordinary slow change
Information from the review book & http://www.ehow.com/about_5118584_ecological-succession.html &
http://www.course-notes.org/Biology/Outlines/Chapter_53_Community_Ecology
http://www.physicalgeography.net/fundamentals/images/succession.gif
http://www.physicalgeography.net/fundamentals/images/succession.gif

http://www.physicalgeography.net/fundamentals/images/succession.gif


Energy Flow Through An Ecosystem

Thermodynamics-Energy can not be either created or destroyed (Law of Conservation of Energy)
-Every energy transfer or transformation increased entropy (disorder) of the universe

When Drawing a food web or food chain, the arrows POINT IN THE DIRECTION OF THE FLOW OF ENERGY.

Plants are exposed t the greatest amount of energy input. This is because after each trophic level, the level before only gives off 10% of the energy that they absorbed. The other 90% that they absorbed was used for their own expenses. Therefore, organisms at the top of the food chain are more exposed to disease and must eat more food in order to acquire a sufficient amount of energy to support them. This is shown in the pyramid below.

external image EnergyPyramid-26a65z5.gif
http://schoolworkhelper.net/2011/01/energy-movement-in-ecosystems-trophic-energy-pyramid/

-MSL
YC
Here is the water cycle. We never went through it thoroughly,but it is a good review.
external image WaterCycle.jpg
http://wacmos.itc.nl/

Phosphorus Cycle:
36-17-PhosphorusCycle-L.gif
http://bioh.wikispaces.com/More+Elemental+Cycles

-MSL

LH:
I found this website really helpful in explaining the difference between primary, gross, and net production, and just energy flow in general. It is a bit lengthy, but I found it helpful.
http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/energyflow/energyflow.html

KEY TERMS OF ECOLOGY
I believe that these terms are extremely important to know, as they are mainframe vocabulary for the section.
Here are the key terms of ecology in summary.
You can quiz yourself on the below listed terms and play games with the terms at:
Quizlet Ecology Review

Happy Studying!

Terms

Definitions

external image spacer.MzUH.gifabiotic
external image spacer.MzUH.gifNONLIVING CHEMICAL AND PHYSICAL FACTORS (IE. AIR, WATER)
external image spacer.MzUH.gifecosystem ecology
external image spacer.MzUH.gifEMPHASIS IS ON ENERGY FLOW AND THE CYCLING OF CHEMICALS AMONG THE VARIOUS BIOTIC AND ABIOTIC COMPONENTS
external image spacer.MzUH.gifcautionary principle
external image spacer.MzUH.gifECOLOGICAL INFO IS ALWAYS INCOMPLETE SO "LOOK BEFORE YOU LEAP"AND REMEMBER "AN OUNCE OF PREVENTION IS WORTH A POUND OF CURE"
external image spacer.MzUH.gifpopulation
external image spacer.MzUH.gifA GROUP OF INDIVIDUALS OF THE SAME SPECIES LIVING IN A PARTICULAR GEOGRAPHIC AREA
external image spacer.MzUH.gifpopulation ecology
external image spacer.MzUH.gifSTUDY CONCENTRATING ON FACTORS THAT AFFECT HOW MANY INDIVIDUALS OF A PARTICULAR SPECIES LIVE IN AN AREA
external image spacer.MzUH.gifcommunity
external image spacer.MzUH.gifALL THE ORGANISMS OF ALL THE SPECIES THAT INHABIT A PARTICULAR AREA
external image spacer.MzUH.gifbiosphere
external image spacer.MzUH.gifTHE SUM OF ALL THE PLANETS ECOSYSTEMS - MOST EXTENSIVE LEVEL IN ECOLOGY - THE PLANET AS A WHOLE
external image spacer.MzUH.gifbiogeography
external image spacer.MzUH.gifTHE STUDY OF PAST AND PRESENT DISTRIBUTION OF INDIVIDUAL SPECIES
external image spacer.MzUH.gifthermocline
external image spacer.MzUH.gifA NARROW STRATUM OF RAPID TEMPERATURE CHANGE IN WATER
external image spacer.MzUH.gifbenthic zone
external image spacer.MzUH.gifTHE SUBSTRATE AT THE BOTTOM OF ALL AQUATIC BIOMES
external image spacer.MzUH.gifdetritus
external image spacer.MzUH.gifDEAD ORGANIC MATTER, MAJOR FOOD SOURCE FOR THE BENTHOS
external image spacer.MzUH.giflittoral zone
external image spacer.MzUH.gifROOTED AND FLOATING AQUATIC PLANTS FLOURISH IN THIS SHALLOW WELL-LIT WATER CLOSE TO SHORE
external image spacer.MzUH.gifestuary
external image spacer.MzUH.gifBOARDERED BY WETLANDS WHERE SALINITY RANGES FROM 1-3%
external image spacer.MzUH.gifpelagic
external image spacer.MzUH.gifOPEN WATER OF ANY DEPTH IS THIS ZONE
external image spacer.MzUH.gifcoral reef
external image spacer.MzUH.gifFOUND IN WARM TROPICAL WATERS IN THE NERITIC ZONE
external image spacer.MzUH.gifclumped
external image spacer.MzUH.gifin groups, clumps
external image spacer.MzUH.gifuniform
external image spacer.MzUH.gifevenly spaced
external image spacer.MzUH.gifrandom
external image spacer.MzUH.gifvaried not in a certain pattern
external image spacer.MzUH.gifeutrophic
external image spacer.MzUH.gifSHALLOW LAKES WITH HIGH NUTRIENT CONTENT, LARGE SURFACE AREA, MURKIER WATERS, HIGH RATE OF PHOTOSYNTHESIS
external image spacer.MzUH.gifmark-recapture
external image spacer.MzUH.gifSAMPLING TECHNIQUE USED TO ESTIMATE FISH AND WILDLIFE
external image spacer.MzUH.gifsurvivorship curve
external image spacer.MzUH.gifA PLOT OF THE PROPORTION OR NUMBERS IN A COHORT STILL ALIVE AT EACH AGE
external image spacer.MzUH.giflife table
external image spacer.MzUH.gifAGE SPECIFIC SUMMARY OF THE SURVIVAL PATTERN OF A POPULATION
external image spacer.MzUH.gifoligotrophic
external image spacer.MzUH.gifLAKES WITH MODERATE AMOUNT OF NUTRIENTS AND PHYTOPLANKTON PRODUCTIVITY
external image spacer.MzUH.gifabyssal
external image spacer.MzUH.gif~3 DEGREES WATER, DARK, EXTREMELY HIGH WATER PRESSURE, LOW NUTRIENT CEONCENTRATION, SOME OXYGEN, DIVERSE POPUL.
external image spacer.MzUH.gifcarrying capacity
external image spacer.MzUH.gifMAXIMUM POPULATION SIZE THAT A PARTICULAR ENVIRONMENT CAN SUPPORT AT A PARTICULAR TIME WITH NO DEGRADATION OF THE HABITAT
external image spacer.MzUH.gifK-selection (equilibrium)
external image spacer.MzUH.gifSELECTION FOR LIFE HISTROY TRAITS THAT ARE SENSITIVE TO POPULATION DENSITY - USUALLY MAXIMIZES POPULATION SIZE
external image spacer.MzUH.gifecological footprint approach
external image spacer.MzUH.gifPROMISING APPROACH TO ESTIMATING THE CARRYING CAPACITY OF EARTH USING SIX TYPES OF ECOLOGICALLY PRODUCTIVE AREAS - ARABLE LAND, PASTURE, FOREST, OCEAN, BUILT-UP LAND, AND FOSSIL ENERGY LAND
external image spacer.MzUH.gifinteractive hypothesis
external image spacer.MzUH.gifADVOCATED BY F.E. CLEMENTS IN EARLY 1900'S, SAW COMMUNITY AS AN ASSEMBLAGE OF CLOSELY LINKED SPECIES ACTING AS SUPERORGANISM
external image spacer.MzUH.gifecosystem
external image spacer.MzUH.gifTHE SUM TOTAL OF ALL SPECIES USE OF THE BIOTIC AND ABIOTIC RESOURCES IN ITS ENVIRONMENT
external image spacer.MzUH.gifniche differentiation
external image spacer.MzUH.gifTHE DIFFERENTIATION OF NICHES THAT ENABLE SIMILAR SPECIES TO COEXIST IN A COMMUNITY
external image spacer.MzUH.gifcharacter displacement
external image spacer.MzUH.gifTHE TENDENCY FOR CHARACTERISTICS TO BE MORE DIVERGENT IN SYMPARTIC PAPULATIONS OF 2 SPECIES THAN IN ALLOPATRIC POPULATIONS OF THE SAME 2 SPECIES
external image spacer.MzUH.gifr-selection (opportunistic)
external image spacer.MzUH.gifDENSITY-INDEPENDENT SELECTION THAT MAXIMIZE REPRODUCTIVE SUCCESS IN UNCROWDED ENVIROMENTS - USUALLY LOGISTICAL CURVE
external image spacer.MzUH.gifsemelparous
external image spacer.MzUH.gifADULTS HAVE A SINGLE OPPOROTUNITY TO PRODUCE LARGE AMOUNT OF OFFSPRING - IE. SALMON
external image spacer.MzUH.gifinclusive model
external image spacer.MzUH.gifSUGGESTION THAT MOST OF THE SPECIES IN A COMMUNITY ARE ASSOCIATED TIGHTLY WITH OTHER SPECIES IN A WEB OF LIFE - COULD BE CALLED INCARNATION OF THE INTERACTIVE MODEL
external image spacer.MzUH.gifinterference competition
external image spacer.MzUH.gifTYPE OF COMPETITIION FOR RESOURCES THAT CAN OCCUR WHEN RESOURCES ARE IN SHORT SUPPLY
external image spacer.MzUH.gifmutualism
external image spacer.MzUH.gifAN INTERSPECIFIC INTERACTION THAT BENEFITS BOTH SPECIES
external image spacer.MzUH.giftop down model
external image spacer.MzUH.gifPOSTULATES THAT IT IS THE PREDATOR THAT CONTROLS COMMUNITY ORGANIZATOIN BECAUSE PREDATORS CONTROL HERBIVORE WHICH IN TURN CONTROL PLANTS WHICH IN TRUN CONTROLS NUTRIENT LEVELS
external image spacer.MzUH.gifbiomass
external image spacer.MzUH.gifTHE SUM WEIGHT OF ALL THE ORGANISMS IN A POPULATION
external image spacer.MzUH.gifparasite
external image spacer.MzUH.gifAN ORGANISM THAT LIVES IN OR ON ANOTHER ORGANISM CAUSING IT HARM
external image spacer.MzUH.gifenergetic hypothesis
external image spacer.MzUH.gifPOPULAR SUGGESTION THAT THE LENGTH OF A FOOD CHAIN IS LIMITED BY THE INEFFICIENCY OF ENERGY TRANSFER ALONG THE CHAIN
external image spacer.MzUH.gifkeystone species
external image spacer.MzUH.gifORGANISMS FEWER IN # BUT HAVE STRONG CONTROL ON COMMUNITY STRUCTURE BY THEIR ECOLOGICAL ROLES/NICHES
external image spacer.MzUH.gifherbivore
external image spacer.MzUH.gifEXTENTION OF PARASITE DEFINITION BY INCLUDING HERBIVORES THAT EAT PLANTS
external image spacer.MzUH.gifcamouflage/cryptic coloration
external image spacer.MzUH.gifA PASSIVE DEFENSE THAT MAKES POTENTIAL PREY DIFFICULT TO SPOT AGAINST ITS BACKGROUND, AKA CAMOUFLAGE
external image spacer.MzUH.gifbatesian mimicry
external image spacer.MzUH.gifA PALATABLE OR HARMLESS SPECIES MIMICS AN UNPALATABLE OR HARMFUL MODEL
external image spacer.MzUH.gifaposematic coloring
external image spacer.MzUH.gifANIMALS WITH CHEMICAL DEFENSES ARE OFTEN BRIGHTLY COLORED
external image spacer.MzUH.gifmullerian mimicry
external image spacer.MzUH.gifTWO OR MORE UNPALATABLE SPECIES RESEMBLE EACH OTHER
external image spacer.MzUH.gifcoevolution
external image spacer.MzUH.gifRECIPROCAL EVOLUTIONARY ADAPTATIONS OF 2 INTERACTING SPECIES
external image spacer.MzUH.gifendoparasite
external image spacer.MzUH.gifA PARASITE THAT LIVES WITHIN THEIR HOST, IE. TAPEWORM
external image spacer.MzUH.gifprimary succession
external image spacer.MzUH.gifAREA WHERE SOIL HAS NOT YET FORMED AND ORGANISMS DID NOT PREVIOUSELY EXIST, IE. VOLCANIC AREA
external image spacer.MzUH.gifconsumer
external image spacer.MzUH.gifORGANISMS THAT CONSUME PRODUCERS
external image spacer.MzUH.gifbiodiversity
external image spacer.MzUH.gifTHE MEASURE OF BIOLOGICAL DIVERSITY CONSIUDERING RICHNESS AND RELATIVE ABUNDANCE
external image spacer.MzUH.gifdetrivore
external image spacer.MzUH.gifORGANISMS THAT CONSUME DEAD ORGANIC MATERIAL AS THEIR PRIMARY SOURCE OF NUTRITION, IE. CATFISH
external image spacer.MzUH.gifgross primary production (GPP)
external image spacer.MzUH.gifTOTAL PRIMARY PRODUCTION OR THE AMOUNT OF LIGHT ENERGY THAT IS CONVERTED TO CHEMICAL ENERGY BY PHOTOSYNTHESIS PER UNIT TIME
external image spacer.MzUH.gifstanding crop
external image spacer.MzUH.gifTOTAL BIOMASS OF PHOTOSYNTHETIC AUTOTROPHS PRESENT AT A GIVEN TIME
external image spacer.MzUH.gifsecondary production
external image spacer.MzUH.gifAMOUNT OF CHEMICAL ENERGY IN CONSUMERS FOOD THAT IS CONVERTED TO THEIR OWN NEW BIOMASS DRUING A GIVEN TIME PEROID
external image spacer.MzUH.gifbiomass pyramid
external image spacer.MzUH.gifEACH TIER REPRESENTS THE STANDING CROP IN A TROPHIC LEVEL, SHAPED LIKE AN UPSIDE DOWN V
external image spacer.MzUH.gifeutrophication
external image spacer.MzUH.gifPROCESS THAT CHANGES POPULATION TYPES IN BODIES OF WATER BY DUMPING NUTRIENT RICH SEWAGE AND FERTILIZER RUNOFF IN TO THE LAKE
external image spacer.MzUH.gifproducers
external image spacer.MzUH.gifORGANISMS AT THE BOTTOM OF THE TROPHIC PYRAMID, AUTOTROPHIC PHOTOSYNTHESIZERS
external image spacer.MzUH.giftropic efficiency
external image spacer.MzUH.gifTHE % OF ENERGY/PRODUCTION TRANSFERRED FROM ONE TROPIC LEVEL TO THE NEXT - USUALLY A FRACTION OF ~10%
external image spacer.MzUH.giftertiary consumer
external image spacer.MzUH.gifORGANISMS USUALLY AT THE TOP OF THE FOOD CHAIN OR PYRAMID, IE. YOU OR A ORCA THAT ATE THE DOLPHIN THAT ATE THE FISH THAT ATE THE SEAWEED
external image spacer.MzUH.gifgreen world hypothesis
external image spacer.MzUH.gifSUGGESTS THAT HERBIVORS CONSUME VERY LITTLE PLANT BIOMASS BECAUSE THEY ARE HELD IN CHECK BY MANY FACTORS
external image spacer.MzUH.gifcritical load
external image spacer.MzUH.gifTHE AMOUNT OF ADDED NUTRIENTS (SUCH AS NITROGEN)THAT CAN BE ABSORBED BY PLANTS WITH OUT DAMAGING ECOSYSTEM INTEGRITY
external image spacer.MzUH.gifammonification
external image spacer.MzUH.gifTHE DECOMPOSITION OF ORGANIC NITROGEN BACK TO AMMONIUM BY BACTERIA AND FUNGI
external image spacer.MzUH.gifbiomagnification
external image spacer.MzUH.gifTHE CONCENTRATION OF HARMFUL TOXINS IN SUCCESSIVE TROPHIC LEVELS
external image spacer.MzUH.gifendangered species
external image spacer.MzUH.gifORGANISMS THAT ARE LIKELY TO BECOME EXTINCT IN THE FORSEEABLE FUTURE THROUGHOUT ALL OR A SIGNIFICANT PORTION OF THEIR RANGE
external image spacer.MzUH.gifecosystem services
external image spacer.MzUH.gifALL THE PROCESS THROUGH WHICH NATURAL ECOSYSTEMS AND THE SPECIES THEY CONTAIN HELP SUSTAIN HUMAN LIFE ON EARTH, IE. NUTRIENT CYCLING, SEED DISPERSAL, PURIFICAITON OF AIR & WATER
external image spacer.MzUH.gifintroduced species
external image spacer.MzUH.gifORGANISMS THAT HUMANS MOVE TO A REGION WHERE THEY WERE NOT PREVIOUSELY FOUND.
external image spacer.MzUH.gifextinction vortex
external image spacer.MzUH.gifDOWNWARD SPIRAL UNIQUE TO SMALL POPULATIONS
external image spacer.MzUH.gifzoned reserve
external image spacer.MzUH.gifAN EXTENSIVE AREA OF LAND THAT INCLUDES ONE OR MORE AREAS UNDISTURBED BY HUMANS SURROUNDED BY LANDS THAT HAVE BEEN CHANGED BY HUMAN ACTIVITY AND ARE USED FOR ECONOMIC GAIN
external image spacer.MzUH.gifmovement corridor
external image spacer.MzUH.gifA SERIES OF SMALL CLUMPS OR A NARROW STRIP OF QUALITY HABITAT THAT CONNECTS OTHERWISE ISOLATED PATCHES OF QUALITY HABITAT

SRF - This walks through how to solve a hardy-weinberg equation


Albinism is only expressed in the phenotype of homozygous recessive individuals (aa). . The average human frequency of albinism in North America is only about 1 in 20,000.
Referring back to the Hardy-Weinberg equation (p² + 2pq + q² = 1), the frequency of homozygous recessive individuals (aa) in a population is . Therefore, in North America the following must be true for albinism:
q² = 1/20,000 = .00005
By taking the square root of both sides of this equation, we get: (Note: the numbers in this example are rounded off for simplification.)
q = .007
In other words, the frequency of the recessive albinism allele (a) is .00707 or about 1 in 140. Knowing one of the two variables (q) in the Hardy-Weinberg equation, it is easy to solve for the other (p).
|| p = 1 - q
||
p = 1 - .007
p = .993

The frequency of the dominant, normal allele (A) is, therefore, .99293 or about 99 in 100.
The next step is to plug the frequencies of p and q into the Hardy-Weinberg equation:
|| p² + 2pq + q² = 1
||
(.993)² + 2 (.993)(.007) + (.007)² = 1
.986 + .014 + .00005 = 1

This gives us the frequencies for each of the three genotypes for this trait in the population:
|| p² =
predicted frequency

of homozygous

dominant individuals

.986

98.6%
2pq =
predicted frequency

of heterozygous

individuals

.014

1.4%
q² =
predicted frequency

of homozygous

recessive individuals

(the albinos)

.00005

.005%

With a frequency of .005% (about 1 in 20,000), albinos are extremely rare. However, heterozygous carriers for this trait, with a predicted frequency of 1.4% (about 1 in 72), are far more common than most people imagine. There are roughly 278 times more carriers than albinos. Clearly, though, the vast majority of humans (98.6%) probably are homozygous dominant and do not have the albinism allele.



MFT

This was the simplest explanation I could find of the carbon cycle. The carbon cycle is essential to all life on Earth since CO2 is required for photosynthesis.

external image carboncy.gif