2. 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 ?

3. Malformed Frogs & Toads

4. 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

5. 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.

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

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

8. MN Frogs and Toads

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

10. 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

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

12. 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.

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

14. Internal Malformations
reproductive
digestive
urinary

15. Malformed Frog Pictures

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

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

23. Types of Agrochemicals
herbicides
Maneb-fungicide
pesticides
propylthiourea
fertilizers

24. 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

25. 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

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

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

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

29. 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

30. 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 ?