The levels of ecological hierarchy are as follows:

1. organism - individual form of life

2. species - organisms that can reproduce fertile offspring

3. population - group of a species living in one area at one time

4. community - group of different populations and their interactions

5. ecosystem - communities and their abiotic surroundings

6. biome - major biotic communities characterized by dominant plant life & climate

7. biosphere - anywhere life is found (aquatic, terrestrial, atmosphere)

Life comes in many forms. A small

pond or untended plot of land may contain dozens or even hundreds of

different kinds of plants and animals. In

contrast, a carefully tended lawn or a commercial timber plantation usually

supports only a few types of grasses or trees. The total number of organisms in

the plantation or lawn may be the same as

the number in the pond or untended plot, but the number of species will be far

smaller.

Within a given region, the variety of

ecosystems is a measure of the ecosystem

diversity. Within a given ecosystem, the variety of species constitutes species

diversity. Within a given species, we can think about the variety of genes as a

measure of genetic diversity.

The number of species in any given place is the most common measure of

biodiversity. Estimating biodiversity can be a challenge. Many species are active

only at night, or are microscopic or live in

places that are not accessible. Scientists have named approximately 2 million

species, but the total must be larger than that. It is estimated there are 8 million

species of beetle in a section of the

Amazon Rain Forest alone.

Species richness is the number of a

species in a given area, such as a pond. Species richness is used to give an

approximate sense of biodiversity in a

particular place. Species evenness tells us if an ecosystem is numerically dominated

by one species or whether all of its species have similar abundances.

COMMUNITIES & INTERACTIONS

Species A 12 11 132Species B 3 2 6Species C 7 6 42Species D 4 3 12Species E 9 8 72

∑ n(n - 1) 264

n n - 1 n(n - 1)

Simpson’s Index • Many diversity indices have been developed that combine different measures of biodiversity. One is called the Simpson’s Index.

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• The Simpson’s Index includes BOTH species richness and species evenness in a single number.

• D is the Simpson’s Index

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• n is the total number of organisms of a particular species

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• N is the total number of organisms of all species

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• ∑ means “add up”!

D =∑ n(n - 1)N(N - 1)

• You have studied a specific site, and have counted the individuals of five different species.

•

• n is the total number of organisms of a particular species.

N = total number of all individuals = 35

N - 1 = 34

N(N - 1) = 1190

D = 2641190 = 0.22184

This area would score 0.22184 on the Simpson’s Index. The scale ranges from 0–1, with 1 representing the lowest biodiversity. Therefore, the score for this area indicates a high level of biodiversity.

This activity uses beads of different colors to look at the concepts species richness and evenness and how they relate to biodiversity and conservation.

Imagine that each color represents a species of animal, and each bead represents one individual of that species.

1 Without looking into the bag, reach in and pull out one bead from Bag A. Record its color in column 1 of the following table. Put the bead back in the bag and pull out a new bead. Record the color in column 2. Repeat to complete the row. Use single-letter abbreviations for the colors (red = R, black = B, etc.). Do the same for Bag B.

Table 1

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Bag A

Bag B

2 Using the numbers from Table 1, add up the number of beads of each color, for each bag, and record the totals in the following table. (Enter the colors of your beads at the head of the columns).

Table 2

Color 1

Color 2

Color 3

Color 4

Color 5

Color 6

Color 7

Bag A

Bag B

3 Refer to data from tables 1 and 2 to contrast and compare the species richness and evenness.

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4 Dump out all of the beads in Bag A and count them. How many beads of each color are there in Bag A? Record the total number of each in the following table. (Enter the colors of your beans at the head of the columns). Repeat for Bag B.

Table 3

Color 1

Color 2

Color 3

Color 4

Color 5

Color 6

Color 7

Bag A

Bag B

5 If each color of bean represents a species, and each bean represents one individual, how many species does each bag have?Does one bag have more than the other?Can you apply the terms "species richness" and "species evenness" to the bags?

6 Which species, in which bag is the most rare? __________

7 If you had the money and resources to save only one of the sites (A or B), which would you save? Why?

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10. Calculate the biodiversity using the Simpson’s Index for Bag A using the data from Table 2, and again for Table 3. Show your work.

CALCULATIONS FOR TABLE 2 CALCULATIONS FOR TABLE 3

While you wait to do the Biodiversity Activity: Read in the Environmental Science for AP textbook pages 124-140. Answer questions 1-10, Drug Resistant E.coli question, parts a, b and d; and Measuring Your Impact question parts a, b and d

#1 #6

#2 #7

#3 #8

#4 #9

#5 #10

Drug Resistancea) 4pts. _______________________________________________________________________________

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____________________________________________________________________________________b) 2pts. _____________________________________________________________________________________

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_____________________________________________________________________________________d) 2pts._____________________________________________________________________________________

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_____________________________________________________________________________________Measuring Impact - Show Equation, answer with correct units.a) 2 pts.______________________________________________________________________________

b) 2 pts.______________________________________________________________________________

d) 2pts. ______________________________________________________________________________

COMMUNITIES & INTERACTIONSNicheEvery species has an optimal environment in which it performs particularly well. All species have a range of tolerance, or limits to abiotic conditions they can tolerate, such as extremes of temperature, humidity, salinity and pH. As conditions move away from the ideal, individuals may be able to survive, and perhaps even grow, but not reproduce. As conditions continue to move away from the ideal, individuals can only survive. If conditions move beyond the range of tolerance, individuals will die. Because the combination of abiotic conditions in a particular environment fundamentally determines whether a species can persist there, the suite of ideal conditions is termed the fundamental niche of the species. The fundamental niche of the Longear Sunfish and the Ozark Shadow Rock Bass overlap almost completely, while the Green Sunfish could survive in warmer, more turbid and slower flowing water.

While the fundamental niche establishes the abiotic limits on a species’ persistence, there are often biotic factors that further limit the physical locations where it can live. Common biotic limitations include the presence of competitors, predators and diseases. For example, even if abiotic conditions are favorable for a plant species in a particular location, other plant species may be better competitors for water and soil nutrients, limiting the growth of the species in that environment. Similarly, if a deadly disease is present, the disease might kill much of a population and prevent the species from persisting. The range of biotic and biotic conditions under which a species actually lives is called its realized niche.

Some species can live under a very wide range of abiotic or biotic conditions, whereas others can live only under a very narrow range of conditions. Organisms that can live in a variety of habitats or feed on a variety of species are considered to be niche generalists. However, other organisms that have limited feeding patterns or living conditions are called niche specialists. An example of a specialist is the koala, who lives in and feeds on only eucalyptus trees. In contrast rats can eat almost anything and live almost anywhere and are considered to be generalists.

An oxymoron?

COMMUNITIES & INTERACTIONSCompetition The struggle of individuals to obtain a limiting resource.Georgii Gause, in 1934 studied two cultures of bacteria P. Aurelia and P. caudatum. Both species were allowed to grow separately in a medium ( ). Then the two species were grown together ( ).When grown separately, both cultures grew in volume to a point, then maintained a steady population size. However, when grown together, P. aurelia increased, although to a lesser volume and P. caudatum declined in volume. This experiment demonstrates the detrimental effects of competing for limited resources such as space and food. Both species were harmed, although one more severely than the other. From this experiment researchers coined the term competitive exclusion principle which states that two species competing for the same limiting resource cannot coexist. One species will perform better and drive the other to extinction. Another way of stating this is that no two species can occupy the same niche in the same place at the same tie.

Competition can lead to resource partitioning, in which two species divide a resource based on differences in the species’ behavior or morphology. In

evolutionary terms, when competition reduces the ability of individuals to survive and reproduce, natural selection will favor individuals that overlap less with other species.

Species in nature reduce resource overlap in several ways. If two species reduce competition by using the same resource but at different times, they are exhibiting temporal resource partitioning.

For example, wolves and coyotes that live in the same territory are active at different times of day to reduce the overlap in the times that they are hunting. Similarly, some plants reduce competition for pollinators by flowering at different times of the year.

If two species reduce competition by using different habitats, they are exhibiting spatial resource partitioning. Desert plants have evolved different root systems to reduce competition for water & nutrients

A third method of reducing overlap is morphological resource partitioning: using the differences in body size or shape. Darwin’s finches developed different beak sizes and shape that allowed each species to eat different foods.

Invasive species, those that enter an ecosystem where it has not lived before, often outcompete native species for limited resources.

Predation

The use of one species as a resource by another species.Organisms of all sizes may be predators and their effects on their prey vary widely. Predators can be grouped into four categories: True predators kill their prey and consume most of what they kill.Herbivores consume plants as prey. They typically eat only a small fraction of an individual plant without killing it.Parasites live on or in the organism they consume, referred to as their host. Because parasites typically consume only a small fraction of their host, a single parasite rarely causes the death of its host. Some parasites are pathogens (disease causing) Pathogenic parasites include some viruses, bacteria, fungi, protists and wormlike organisms called helminths Parasitoids are organisms that lay eggs inside other organisms. When the eggs hatch, the parasitoid larvae slowly consume the host from the inside out, eventually leading to the host’s death. Parasitoids include certain species of wasps and flies.

Predators can play an important role in controlling the abundance of prey in nature. In the graph, lynx prey on hares. Consistent with the concept of energy flow, there are fewer carnivores in any given ecosystem then there are primary consumers. Therefore there will most often be fewer lynx than hares in this example. However, note the trend. If the hare population (prey) increases, then food is more available for the lynx. Competition is reduced and more available energy can be used to reproduce. Therefore, following an increase in the number of prey, there is normally an increase in the number of predators. Likewise, if the population of prey decreases, then soon to follow will be a decline in the population size of the predator.If disease or some other factor reduced the number of predators, the number of prey will increase dramatically.

To avoid being harmed, some species have evolved to have defenses, such as emitting chemicals that are toxic or fowl smelling or tasting. Others mimic the appearance or behavior of species that are deadly. For example coral snakes and milk snakes are both striped red, yellow and black. The coral snake is deadly, while the milk snake is without venom.This is a type of camouflage called mimicry.

Mutualismis a type of interspecific interaction that benefits two interacting species by increasing both species’ chances of survival and/or reproduction. Among mutualistic interactions are those of plants and their pollinators, which include birds, bats and insects. Without pollination the plants can not reproduce. The pollinators are rewarded with a

food source. Many flowers have specific shapes, colors or fragrance to attract pollinators.Nemo had a mutualistic relationship with sea anemones, but perhaps lesser known is the mutualistic relationship of lichen.Lichen are colonies of an alga and fungus. The fungus provides nutrients the alga needs and the alga provides carbohydrates for the fungus via photosynthesis. Lichen therefore can grow on bare rock and is abundant in the Wichita Wildlife Refuge as well as throughout the world. In the winter, lichen provides a food source for herbivores.

Commensalism is a type of symbiotic relationship in which one species benefits, but the other species is neither harmed nor benefited. Birds perch in trees and fish hide among the coral are examples of commensalism. Commensalism, mutualism and parasitism are all symbiotic relationships, that is the two species live in close association with each other.

Amensalism is a relationship between two organisms in which one species is harmed, but there is no effect on the other species. An example is the fungus penicillium naturally gives off a substance that is toxic to most bacteria. The bacteria are killed, but the fungus is unaffected.

Keystone species are those whose niche in a community is more important than its relative abundance might suggest. The term suggests that if this species were to disappear, the rest of the community would collapse.

The Pisaster (starfish) is such a species. When the starfish was removed from the coast of Washington State, the mytilus mollusk outcompeted the other species in the community. The population size of 25 other species declined without the predatory starfish to keep the mollusk population in check.

Prairie dogs are considered a “keystone” species because their colonies create islands of habitat that benefit approximately 150 other species. They are a food source for many animals, including coyotes, eagles, badgers, and the critically endangered black-footed ferret. Many species, like the black-footed ferret and tiger salamander, use their burrows as homes. Prairie dogs

even help aerate and fertilize the soil, allowing a greater diversity of plants to thrive.Other examples are beavers and sea otters. (Research)

An indicator species is a species whose presence, absence, or relative well-being in a given environment is indicative of the health of its ecosystem as a whole.Historically, caged canaries that mining workers would carry down into the mine tunnels with them, sang almost endlessly. If dangerous gases such as methane or carbon monoxide leaked into the mine, the gases would kill the canary before killing the miners, thus the silence provided a warning to exit the tunnels immediately.In nature, amphibians such as frogs are excellent indicator species as they live part of their life in water and part on land. In addition, their skin is quick to absorb substances from the water, soil and air. Therefore any toxics in any part of the ecosystem will have a more immediate affect on these animals. E-coli, an intestinal bacteria, is generally harmless, but its presence often indicates that waste from mammals that is harmful is likely present. Without E-coli, we would not be able to digest food, but when found in a water supply indicates other fecal material makes the water not potable.

Disease-causing organismsHuman wastewater can carry a variety of illness-causing viruses, bacteria and parasites that are called pathogens. Pathogens in wastewater are responsible for a number of diseases that can be contracted by humans or other organisms that come in contact with or ingest the water. The table lists a few common waterborne diseases

DISEASE PATHOGEN ROUTE OF EXPOSURE

CHOLERA BACTERIA GASTRO-INTESTINAL

BOTULISM BACTERIA GASTRO-INTESTINAL

TYPHOID BACTERIA GASTRO-INTESTINAL

HEPATITIS A VIRUS GASTRO-INTESTINAL

DYSENTERY AMOEBA OR BACTERIA GASTRO-INTESTINAL

CRYPTOSPORIDIOSIS PROTOZOA GASTRO-INTESTINAL

POLIO VIRUS GASTRO-INTESTINAL

GIARDIA PROTOZOA GASTRO-INTESTINAL

Cholera claims thousands of lives annually in developing countries, but is not common in the United States. Cryptosporidiosis has caused a number of outbreaks of gastrointestinal illness in this country. Large-scale disease outbreaks from municipal water systems are rare in the United States, but they do occasionally occur.

The World Health Organization (WHO) estimates that 1.1 billion people, almost 1/6 of the world’s population, do not have access to sufficient supplies of potable (safe drinking) water. Half of the 3.1 million annual deaths from diarrheal diseases and malaria could be prevented with safe drinking water, proper sanitation and proper hygiene.

The Safe Drinking Water Act (SDWA) is the main federal law that ensures the quality of Americans' drinking water.Under SDWA, EPA sets standards for drinking water quality and oversees the states, localities, and water suppliers who implement those standards.

SDWA was originally passed by Congress in 1974 to protect public health by regulating the nation's public drinking water supply. The law was amended in 1986 and 1996 and requires many actions to protect drinking water and its sources: rivers, lakes, reservoirs, springs, and ground water wells.

The Clean Water Act (CWA) is the primary federal law in the United States governing water pollution.[1] Passed in 1972, the act established the goals of eliminating releases of high amounts of toxic substances into water, eliminating additional water pollution by 1985, and ensuring that surface waters meet standards necessary for human sports and recreation such as swimming and fishing.

Indicate the type of relationship for each example below.1. A cleaner fish feeds off of the decaying food stuck in a shark’s teeth. As a result, the shark’s teeth stay

healthy.

2. A cheetah chases down a rabbit and eats it.

3. Barnacles attach themselves to the skin of whales. The barnacles have water passing over them which allows them to get food and the whale is unaffected.

4. A dandelion grows in a grassy field and uses almost all the soil nutrients

5. A type of bacteria lives in the gut of termites. The bacteria allows the termite to digest wood. The bacteria feeds off the nutrients in the gut.

6. Lichen is a symbiotic relationship of alga and fungus. The fungus gains nutrients synthesized from the alga and the alga receives water and nutrient salts from the fungus.

Write the vocabulary term for the following definitions.1. entire range of conditions an organism is potentially able to occupy

2. number of species in the community

3.All the different populations that live together in an area at the same time.

4. Anything that restricts the number of individuals living in a population

5. An organism’s particular role in an ecosystem.

6. A species that enters an environment where it has not lived before and often outcompete indigenous species.

Short Answer1. How do keystone species illustrate the interdependence of organisms living in the community. Give a

specific example with explanation._______________________________________________________________________________________

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_______________________________________________________________________________________2a. In a particular deciduous forest, leaf litter is critical to the survival of local species of forest plants. What are two possible roles of leaf litter in this particular environment?

______________________________________________________________________________________b. Describe 3 abiotic changes if exotic invasive worms consumed all the leaf litter in a single year.

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_____________________________________________________________________________________d. Design a controlled experiment to determine whether the worms, in fact, do change the forest ecosystem.

Identify the dependent variable and specifically how it will be measured, include a specific hypothesis and examples of the probably data you will collect.

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_____________________________________________________________________________________Example Data: