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  • Predator-Prey Relationship Dynamics

    Predator-Prey Relationship Dynamics

    Data Point

    In a study in Greenland, scientists examined whether changes in population densities of Arctic fox are related to changes in population densities of its main prey, the lemming.

  • Tracking Genetically Modified Mosquitoes

    Tracking Genetically Modified Mosquitoes

    Activity

    Genetically modified mosquitoes have been used to reduce mosquito populations and the diseases they spread. But how can we tell if the method works? In this activity, students analyze data from a field experiment.

  • Population Dynamics

    Population Dynamics

    Click & Learn

    Explore the exponential and the logistic growth mathematical models that describe how population changes with time.

  • Portrait of a Howler

    Portrait of a Howler

    Image of the Week

    Groups of black howler monkeys (Alouatta caraya) “howl” to each other in the Amazon rainforest during the evening and early morning hours in order to maintain neighborly distances.

  • Benefits of Schools

    Benefits of Schools

    Image of the Week

    Being in a school affords young barracuda several advantages over the solitary life.

  • Counting the Rings

    Counting the Rings

    Image of the Week

    An otolith from a lanternfish (Gymnoscopelus nicholsi) is used to estimate the fish’s age and growth rate.

  • Climate Stress and Coastal Food Webs

    Climate Stress and Coastal Food Webs

    Lecture

    (43 min 18 sec) We are in the midst of a major die-off of coastal wetlands – what is to blame?

  • Floods, Droughts, and Food Chains

    Floods, Droughts, and Food Chains

    Lecture

    (44 min 27 sec) How a river's community of herbivores and predators is affected by changes in river flow.

  • Untangling Salt Marsh Food Webs

    Untangling Salt Marsh Food Webs

    Lecture

    (45 min 16 sec) The revelation that salt marshes are controlled by top-down forces of herbivores and other consumers.

  • Trophic Cascades in Rivers

    Trophic Cascades in Rivers

    Lecture

    (44 min 27 sec) How fishes in a river ecosystem play a critical role in forming the aquascape.

  • Ecology of Rivers and Coasts—Food Webs and Human Impacts

    Ecology of Rivers and Coasts—Food Webs and Human Impacts

    Lecture

    Two leading ecologists describe the complex interactions between species and their environment in aquatic ecosystems. 

  • The Great Elephant Census Modeling Activity

    The Great Elephant Census Modeling Activity

    Activity

    In this classroom activity, students will model two types of counting methods, sample counts and total counts, to determine population size. 

  • Exploring Trophic Cascades

    Exploring Trophic Cascades

    Click & Learn

    This interactive explores examples of what can happen when there are changes in the population size of one species in an ecosystem. How are species at other trophic levels affected? How does the ecosystem change?

  • Following the Matriarch

    Following the Matriarch

    Image of the Week

    A herd of elephants moving across the floodplain grassland of Gorongosa National Park.

  • Discovering Keystone Species

    Discovering Keystone Species

    Poster

    This classroom poster illustrates Robert Paine’s pioneering experiment that demonstrated the importance of top-down regulation of ecological communities by predators and led to his coining of the term keystone species.

  • Film Guide for Some Animals are More Equal than Others

    Film Guide for Some Animals are More Equal than Others

    Film Guide

    The following classroom-ready resources complement the film Some Animals Are More Equal Than Others: Trophic Cascades and Keystone Species. It tells the story of the bold experiments by Robert Paine and James Estes, which established the importance of keystone species in regulating ecological communities and the cascades of effects set in motion by their removal.

  • Using Genetic Evidence to Identify Ivory Poaching Hotspots

    Using Genetic Evidence to Identify Ivory Poaching Hotspots

    Data Point

    A team of scientists analyzed the DNA from seized ivory to determine where the ivory from poached elephants came from.

  • CSI Wildlife

    CSI Wildlife

    Click & Learn

    In this interactive, students use DNA profiling, or fingerprinting, to solve two cases of elephant poaching. In the process they will learn about genetic markers, PCR, gel electrophoresis, allele frequencies, and population genetics.

  • Survey Methods

    Survey Methods

    Click & Learn

    In this interactive, students explore the methods scientists use to survey elephants and learn about the current state of the elephant population in Africa.

  • The Great Elephant Census

    The Great Elephant Census

    Scientists at Work

    (8 min 23 sec) How many African elephants are left and where are they? This video follows the work of researchers conducting the first census of African savanna elephants in over 40 years and the methods they are using to obtain accurate, up-to-date numbers across the continent. 

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