Do Now - In the early 1990’s Students and Scientists in Minnesota and elsewhere had found malformed frogs. Then the issue hit the national media in 1995. Why would this be important to humans ?

Malformed Frogs & Toads

Frogs and Toads 3,300 species in the world 92 species in USA 14 species in MN 92 species in USA 3,300 species in the world

Vs. Frogs have: Toads have: smooth or slimy skin warty and dry skin strong, long legs and stubby bodies with short webbed hind feet hind legs two bulging eyes parotid glands behind eyes lay eggs in clusters lay eggs in long chains Both are Cold blooded - their body temperature adjusts with the outside environment.

glass Frog Red-eyed Treefrog poison dart frog White’s Treefrog Horned Toad Fire-bellied Toad

Ornate Horned Frog poison dart frog African Dwarf Frog Strawberry Poison Dart Frog

MN Frogs and Toads

Habitats for frogs and toads forests grasslands lakes, ponds, marshes rivers and streams

Why We Care Frogs and toads are a part of the planet’s bio-diversity. 2. Frogs and toads interact in interesting ways with each other and the environment, i.e. both prey and predators

3. Frogs As Bio-indicators 1) Double life—amphibious What does this mean ? 2) Permeable skin 3) Absorb and concentrate toxins--biomagnification

Biomagnification Biological magnification is when certain substances such as pesticides or heavy metals like mercury move up the food chain, work their way into rivers or lakes, and are eaten by aquatic organisms such as fish, which are then eaten by large birds, animals or humans.

External Malformations extra or missing limbs branching limbs spikes or protuberances missing eyes abnormal webbing

Internal Malformations reproductive digestive urinary

Malformed Frog Pictures

Causes of Malformations genetic origins parasite disruption of limb formation chemical contamination viruses ultraviolet radiation physical trauma (predation, people)

Possible Chemical Contaminants Agrochemicals (pesticides) Heavy metals Acid Rain (sulphur dioxide reacting with rain) Chlorofluorocarbons (CFCs)

Types of Agrochemicals herbicides Maneb-fungicide pesticides propylthiourea fertilizers

Correlations to Human Health Concerns high nitrate levels (from fertilizers) in human drinking water and frog breeding ponds are hazardous human birth defects result from pesticide application UV radiation results in blindness and skin cancer in humans and other animals; DNA damage in developing frog eggs

Where have all the frogs gone? Global Population Decline a concern during the past decade frog declines widespread and well-documented possible causes include habitat destruction, increased UV radiation, and chemical contamination

Global Population Declines Loss of habitat from filling in wetlands to create more farmland for crops, and to build more houses and roads

Global Population Declines Increasing ultraviolet radiation Pollution by chemicals Acid rain Pathogens Parasites Introduction of non-native species

Global Population Declines Monteverde, Costa Rica: Golden Toad last seen 1988

Global Population Declines Other places experiencing declines include: Puerto Rico Ecuador Venezuela Brazil U.S. Rocky Mountains Cascade Mountain Range in Washington, Oregon, and California

Exit Card In order to leave class you must hand in a sheet of paper with the following questions answered…. Why do we care if there are frogs living with malformations ? How can this information help humans ?