Modeling the Impact of Pollution and Predators on a Population of

Northern Leopard Frogs

By Kevin and Zack

Habitat range

• Lakes, streams, ponds, and marshes.

• Green, sometimes light brown.

• Mutated frogs, Minnesota, 1995.

• Turtles, snakes, lizards, birds.

NORTHERN LEOPARD FROG

• Life cycle of frog.

• Damage via pollution.

• Predatory animals.

A MATHEMATICAL REPRESENTATION

MODELING THEFROG LIFE CYCLE

• Three stages.

•Lizards eat only adult frogs.

•Pollution affects all frogs.

• Eggs laid: ~4.1/day/adult

• Eggs hatching: 12 days

• Tadpoles maturing: 60 days

• Population cap: 400 for adults, 1250 overall

MORTALITY DUE TO POLLUTION

Pollution kills:4% tadpoles, eggs.2% adult frogs.

FROGS’ PREDATORS (LIZARDS)

• Lizards live 4 years.• Birth rate based on food.• 2 frogs/lizard/day.

THE COMPLETED MODEL

POPULATIONS DURING A 1,400-DAY TRIAL

• Populations shoot up• Lizards catch up tofrogs• Equilibrium reached

FROG MORTALITIES BY CAUSE

• More deaths due topollution• Lizards eat more,but only adults• Pollution affects all frogs

Conclusion• Pollution affects a population of frogsmore than predators.

Are there any questions? No? Great!

Bibliography

•Dunn, Kyla, “Freaky Frogs”, www.pbs.orgfrontline.online, 1998.

•Oregon State University, “Methroprene”, www.ace.orst.edu/info/extoxnet/pips/methroprene.htm, 1996

•Three Teachers’ Association, “The Northern Leopard Frog”,www.alienexplorer.com/ecology/p146.html, 2000

•Province of Nova Scotia, “Northern Leopard Frog”, http://museum.gov.ns.ca/mnh/nature/frogs/north.htm, 2000