Introduction

This reader was developed for a course entitled "Ecology for Teachers" offered through the Department of Biological Sciences at Texas Tech University.  This distance-ed graduate level course is designed for in-service high school teachers enrolled in a Multidiscplinary Science Masters Degree offered at Texas Tech University.  Thus, this course is intended to provide teachers with the background necessary to teach ecology content at the high school level.  My philosophy is that teachers are the experts in the pedagogies that are most effective for teaching their students.  My job in this course is to provide the content knowledge necessary for teachers to be able to create effective learning opportunities for their students.

Organization of the Course 

Ecology is the study of the interactions between organisms and their environments.  Interactions with the abiotic (non-living) and biotic environment influence  global patterns of distribution and abundance as well as the characteristics of organisms living in different environments.  Thus, in order to understand the global patterns it will be necessary to understand something about the factors that influence the physical environment of the planet.   The fact that organisms interact with their environment over time means that we have to study ecology in an evolutionary context.  Ecology plays out at different hierarchical levels. Understanding what happens at one level often requires an understanding of factors operating at the levels below and above them.  Finally, these interactions produce emergent properties such as patterns of biodiversity and environmental problems. 

Thus, this course is divided into the following sections.

1. The Physical Environment

2. The Evolutionary Context

3. Hierarchical Organization of Ecology

• Individuals
• Populations
• Communities
• Ecosystems
• Landscapes
• Biomes
• Biosphere

4. Emergent Properties

• Biodiversity
• Environmental Issues

Texas Essential Knowledge and Skills and the National Science Standards

The science curriculum in Texas is driven by the Texas Essential Knowledge and Skills (TEKS) and advised by the National Science Education Standards.  This course will include topics covered in the High School section of  TEKS 112.43. Biology, 112.44.Environmental Systems, and 112.49. Geology, Meteorology, and Oceanography. 

Expected Learning Outcomes

Because this course is intended for high school teachers, the level of mastery expected in this course is one that will allow teachers to apply this information in their classrooms.  For each section of the course I have listed expected learning outcomes and the relationship between specific learning outcomes and objectives in the TEKS.

1. The Physical Environment

Introduction 

The physical factors such as temperature and precipitation vary widely across the planet.  Not surprisingly, variation in these factors has a strong influence on characteristics of individual organisms, and patterns of population dynamics, community structure, and ecosystem function across  the earth.  Thus, an understanding of the factors that influence global variation in climate should be helpful when trying to understand global variation in phenotypes, population dynamics, community structure, and ecosystem functioning.  This section of the course will (1) examine global patterns of variation in the physical environment, and (2) discuss the causes of these patterns.  Studying the factors that influence the global physical environment is an important area of connection between earth sciences, atmospheric sciences, and the life sciences.

Required Readings

Ecology

Climate  read the following sections

• What is climate?
• What is the climate system
• What factors determine earth's climate?

Solar radiation

Atmospheric effects on incoming solar radiation

Precipitation and fog

Global distribution of precipitation

Introduction to the Atmosphere

ocean circulation

AP Environmental Science Chapter 4- The Atmosphere

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• describe global patterns of variation in temperature and precipitation and be able to explain the causes of these patterns (TEKS 112.49. 13B). 
• develop curricular material to teach students how to understand the causes of their local climate and how and why the local climate differs from the climate found in other locations around the earth (TEKS 112.49. 13B).

2. The Evolutionary Context

Introduction

Ecology is affected by factors that act at different temporal scales.  For example, the biodiversity of organisms is affected by macroevolutionary processes such as speciation and extinction that take place over long periods of time (evolutionary time).  In addition, the distribution and abundance of organisms is influenced by factors taking place in ecological time. 

Required Reading

Evolution

Natural selection

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• explain how the process of natural selection has produced a trait that has increased an organism's survival or reproduction in a particular environment (TEKS 112.43. 7B).
• identify and describe behavioral, physiological, and morphological adaptations to a particular environment (TEKS 112.43. 7B).
• develop curricular materials to teach students how and why the traits of similar organisms can be different across different environments (TEKS 112.43. 7B & 12C).

3. Hierarchical Organization of Ecology

Ecological interactions take place at different levels of hierarchical organization.  Interactions at one level often affect interactions at the next higher level of organization (e.g, characteristics of individual organism can influence patterns of population dynamics), and vice versa.  In this section we will examine ecological interactions occurring at the individual, population, community, ecosystem, biome, and biosphere levels.  

Individual traits

The process of natural selection should result in traits that adapt animals to their environments.  There are many examples of adaptations at the physiological, morphological, behavioral, and reproductive levels in animals, plants, and microbes.  As an example of how organisms can adapt to extreme environments, we will focus on the adaptations of desert animals and plants. 

Adaptations to desert environments

Desert environments are characterized by low precipitation and often deserts have high temperatures.  Thus, organisms living in desert environments face challenges of obtaining water, reducing  water loss, regulating their body temperatures, finding food, and reproducing in such harsh environments.

Required Reading

Desert biome

Adaptations of desert birds and mammals

Adaptations of desert amphibians and reptiles

Adaptations of desert plants

Pollination ecology of desert plants

Seed dispersal of desert plants

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• identify and discuss the unique challenges associated with living in arid environments (TEKS 112.43 12C)
• explain adaptations of animals and plants for water uptake and water conservation (TEKS 112.43. 7B)
• explain adaptations of animals and plants for dealing with high temperatures (TEKS 112.43. 7B
• develop curricular materials to teach students about adaptations to arid environments TEKS 112.43. 7B)
• develop curricular materials to teach how animals or plants are adapted to a different (non-desert) environment ((TEKS 112.43. 7B & 112.43.12B)

Population Ecology

Even casual observers have noticed that the abundance of animals and plants varies over time.  For example, the numbers of mosquitoes in my back yard right now is unusually high (probably in response to the record precipitation that we received last month).  In addition, most of us have recognized that different species vary in abundance.  For example, while driving at night through West Texas I am much more likely to see a jack rabbit along the side of the road than I am to see a coyote.  What causes population sizes to vary among species and population size of a species to vary over time?

Population ecologists study the factors that influence population growth rates and population sizes.  Because population ecology focuses on numbers and rates it is a fairly quantitative field.  Thus, population ecologists use math and graphs to help them understand patterns that influence population growth.   Many students (and teachers) are uncomfortable using math and graphs.  The study of population ecology offers an ideal opportunity to integrate mathematics into the science classroom.   Thus, it is critical that science teachers become comfortable enough with mathematical and graphical approaches to studying ecology that they are able to teach the information to their students.

Required Reading

Population ecology focuses on the factors that influence population growth and the population size (see population). 

Exponential growth

logistic growth

carrying capacity

Intraspecific competition

human population explosion

Malthus, Thomas

ecological footprint

AP Environmental Science Chapter 6- History and Global Distribution

AP Environmental Science Chapter 7- Carrying Capacity

AP Environmental Science Chapter 8- Cultural and Economic Influences

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• draw, interpret, and teach the following graphs associate with exponential growth (TEKS- 112.44. 7B)

                   how population size change over time in exponential growth          

                   how population growth rate varies over time in exponential growth

                   how per capita growth rate changes over time in exponential growth

• teach the relationship between the exponential growth equation and the graphs listed above (TEKS- 112.44. 7B)
• explain why exponential growth is an unrealistic pattern of growth for most species (TEKS- 112.44. 7A)
• define and teach the carrying capacity (TEKS- 112.44. 7A)
• draw, interpret, and teach the following graphs associated with logistic growth (TEKS- 112.44. 7A)

           how population size changes over time in logistic growth when the initial population size is much smaller than the carrying capacity          

           how the population size changes over time in logistic growth when the initial population size is much larger than the carrying capacity

•  develop curriculum to teach aspects of population growth (TEKS- 112.44. 7A & 7B)
•  discuss patterns of human population growth, focusing on the differences between the patterns in developed and developing countries
•  explain possible implications of human population growth (TEKS- 112.44 4C & 5F)

Community Ecology

No organism exists alone in the environment.  All organisms require food and energy and many species rely on other organisms as a food source.  In addition, all organisms are a potential source of food for other organisms and all organisms are potential hosts for parasites and diseases.  Thus, organisms are involved in a complex web of interactions with other members of their community.  Because these interactions can be complicated, we will start by discussing single interactions at a time and then build to studying more complex interactions.

Competition

Resources such as food, water, light, soil nutrients, safe sites, and females may be in short supply.  When resources are limited individuals will be expected to complete not only with members of their own species (intraspecific competition) but also with members of other species (interspecific competition).  Competition can affect population sizes and community composition.

Required Reading

competition

Interspecific competition

Exploitative competition

competitive exclusion principle

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• identify and explain examples of exploitative and interference competition from a variety of environments (TEKS 112.43. 12 B & 12 E and TEKS 112.44. 4 A).
• define the competitive exclusion principle and explain how this principle can influence patterns of community structure (TEKS 112.43. 12 B & 12 E).
• develop curricular materials to illustrate competition in a particular environment (TEKS 112.43. 12 B & 12 E and TEKS 112.44. 4 A).

Predation

All organisms require energy and nutrients to survive.  Plants, an example of a primary producer, get the energy they require by converting sunlight energy into chemical energy through the process of photosynthesis.  Because they are unable to photosynthesize, animals must get their energy by consuming other organisms.  Thus, there should be strong selection to assure (1) that animals are good at getting food, and (2) good at avoiding becoming food for another animal.  Predation is an important source of mortality, and can affect population growth rates and population sizes.  In addition, predation can play an important role in determining which, and how many, species are found living in a community.

Required Reading

Predation

Herbivory

Parasite

Predator-prey cycles

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• identify and explain examples of predation, herbivory, and parasitism from a variety of environments (TEKS 112.43. 12 B & 12 E and TEKS 112.44. 4A).
• identify examples of morphological and behavioral adaptations that animals have to help capture their food (TEKS 112.43 7B, 12B)
• identify examples of morphological, biochemical, or behavioral adaptations that animals have to protect them from predators (TEKS 112.43 7B, 12B)
• explain the role that predation plays in regulating population sizes of species (TEKS 112.43. 12 B & 12 E and TEKS 112.44 7A).
• explain how predation can influence the species richness of a community (TEKS 112.43. 12B)
• develop curricular material to illustrate predation in a chosen environment (TEKS 112.43. 12 B & 12 E and TEKS 112.44. 4A).

Mutualisms

Sometimes interactions between species can benefit both species involved.  Mutualisms play important roles in many ecological communities.

Required Reading

Mutualism

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• identify and explain examples of mutualisms from a variety of habitats (TEKS 112.43. 12 B and 12 E).
• explain the role that mutualisms can play in determining community structure (TEKS 112.43. 12 B and 12 E).
• develop curricular materials to illustrate mutualism in a chosen environment (TEKS 112.43. 12 B and 12 E).

Food Webs and Indirect Effects

Up to now we have examined the effect of only a single ecological interaction at a time.  However, in the real world, organisms live in complex webs where every species competes for resources with other species and every species is potentially a food source of other species.  Not surprisingly, trying to understand the effects of interspecific interactions is much harder when species are living in complex communities than when we are studying the effects of ecological interactions two species at a time.  Determining the outcome of ecological interactions is complicated because organisms have both direct and indirect effects on each other.

Required Reading

food web

indirect effects

keystone species

Bottom-up control

Top-down control

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• determine the position of a species in the food chain (TEKS 112.43 10D, 12B, 12E and TEKS 112.44 6B)
• distinguish between direct and indirect effects and provide examples of indirect ecological effects occurring in specific communities (TEKS 112.43 12B)
• identify examples of keystone species and explain how they influence their ecosystem (TEKS 112.43 12B and TEKS 112.44 4D, 4E)
• distinguish between bottom-up and top-down community regulation (TEKS 112.43 12B and TEKS 112.44 4D, 4E)

Ecosystem Ecology

Unlike population and community ecologists who focus their attention on organisms, the focus of ecosystem ecologists shifts to studying the flow of energy and nutrients through ecosystems. 

Energetics

Required Reading

Ecosystem

Ecological energetics

Energy flow

Flow of Energy

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• identity the source of most energy used by biological organisms on earth and explain the energy transformations experienced by this energy (TEKS 112.43. 9D,12A, & 12E and TEKS 112.44. 6A, 6B, & 6D)
• diagram the energy pyramid and explain why it has the shape it does and how it affects population structure at different trophic levels (TEKS 112.43. 9D & 12A and TEKS 112.44. 6B, 6C, & 6D).
• diagram food chains and food webs from a variety of environments (TEKS 112.43.  9D, 12A, & 12E and TEKS 112.44. 6B, 6C, & 6D).
• develop curricular materials to illustrate the food web and pattern of energy flow in a chosen environment (TEKS 112.43.  9D, 12A, & 12E and TEKS 112.44. 6B, 6C, & 6D).

Hydrologic Cycle

Required Reading

Hydrologic cycle 

AP Environmental Science Chapter 9- Water

AP Environmental Science Chapter 2- The Cycling of Matter

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• diagram the hyrdrologic cycle  (TEKS 112.43. 12A and TEKS 112.44. 10A).
• develop curricular materials to explain the hydrologic cycle (TEKS 112.43. 12A and TEKS 112.44. 10A).

Nutrient Cycling

Required Reading

Nitrogen

Nitrogen cycle

Carbon

Carbon cycle

Global material cycles

AP Environmental Science Chapter 2- The Cycling of Matter

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• diagram the nitrogen cycle within an ecosystem and explain how the rate of movement from one reservoir to the next can vary between environments (TEKS 112.43. 12A & 12E).
• diagram the global carbon cycle and be able to explain how human activity has altered this cycle (TEKS 112.43. 12A).
• develop curricular material to illustrate nitrogen cycling withing a chosen environment (TEKS 112.43. 12A & 12E).

Ecosystem Functioning and Ecosystem Services

Required Reading

Natural capital

Species influences upon ecosystem function

Marine ecosystem services

AP Environmental Science Chapter 12- Biological

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• discuss ecosystem services provided by species in both terrestrial and marine environments (TEKS 112.44 5E)

Landscape Ecology

Required Reading

Landscape ecology

Landscape ecology: Its role as the scientific underpinning of land-use planning

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• define the field of landscape ecology
• discuss how an understanding of landscape ecology can be useful for land-use planning

Biomes

Readings

Biomes

Terrestrial biome

Tundra biome

Taiga

Forest biome

Grassland biome

Desert biome

Marine biomes

Ocean

Coral reef

Estuary

Salt marsh

Tidal marsh

Seagrass meadows

Mangrove swamp

Freshwater biomes

Wetland

Marsh

Swamp

Bog

Fens

Prairie pothole

Riparian zones

Lakes

Playa lakes

Spring

Anthropogenic biomes

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• identify the important terrestrial and marine biomes (TEKS 112.43 12C and TEKS 112.44 4A)
• explain the factors that determine where biomes are located (TEKS 112.43 7B, 12C)
• explain how the physical environment of a biome influences the characteristics of species living in that biome (TEKS 112.43 13A)
• compare and contrast the different biomes (TEKS 112.43 12C and TEKS 112.44 4A)
• discuss the characteristics of anthropogenic biomes (TEKS 112,44 4C

Biosphere

Required Reading

Biosphere

AP Environmental Science Chapter 5- The Biosphere

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• define the biospere

4. Biodiversity

Required Readings 

Biodiversity 

species diversity

Species richness

Genetic variation

Biodiversity fact sheet

Biodiversity and ecosystem services

Biodiversity hotspots (collection)

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• define biodiversity and explain the various components of diversity including genetic diversity, species diversity, and functional diversity (TEKS 112.43. 7B)
• discuss the factors that influence diversity in an ecological community (TEKS 112.43. 7B, 12A, & 12E and TEKS 112.44 6C)
• explain why biodiversity is important (TEKS 112.44 4E)
• compare threats to biodiversity in their local region with those  in a distant region (TEKS 112.44 4E)

5. Environmental Issues

There are many environmental issues facing us today.  Although this course does not explicitly focus on environmental issues affecting humans, I think that it is important for people to have a basic understanding of ecology in order to be able to understand most environmental problems.  Moreover, many current environmental issues provide the opportunity to apply what we have learned about ecology to help us understand and potentially to help us deal with these problems.

Invasive species

The addition of a novel species to a community, either by the intentional or unintentional activity of human or my natural migration, introduces novel ecological interactions into an ecosystem.  Not surprisingly, introduced species can have profound and often unexpected effects in a community.  Thus, understanding the role of invasive species in ecological communities is an excellent topic to apply our newly developed understanding of ecology.

Required reading

Invasive species

Exotic species

Marine invasive species

Aquatic invasive species

Invasion fact sheet

Expected Learning Outcomes

At the end of this course a fully engaged student should be able to

• discuss the variety of mechanism through which novel species are introduced into a community (TEKS 112.43. 12B & 12E and TEKS 112.44. 4C, 4D, & 4E)
• identity examples of introduced species in your own area
• identify examples where introduced species have caused economic and environmental damage to an ecosystem (TEKS 112.43. 12B & 12E and TEKS 112.44. 4C, 4D, & 4E)
• explain why introduced species might often have large negative effects in communities (TEKS 112.43. 12B & 12E and TEKS 112.44. 4C, 4D, & 4E)
• discuss potential ways to limit invasions or to remove novel species (TEKS 112.43. 12B & 12E and TEKS 112.44. 4C, 4D, & 4E)

Review of Some Other Issues

Your students are constantly receiving information about environmental issues through the media.  The following articles will provide some background information that will allow you to accurately discuss these issues with your students when they arise.

Required Reading

AP Environmental Science Chapter 16- Air, Water and Soils

AP Environmental Science Chapter 17- Solid Waste

AP Environmental Science Chapter 18- Human Health

AP Environmental Science Chapter 19- First-Order Effects

AP Environmental Science Chapter 20- Higher-Order Effects

Expected Learning Outcomes

By the end of this course the fully engaged student should be able to

• discuss current environmental issues with their students in an ecological context