An Introduction to Ecology Silence of the Frogs Please help us! An Introduction to Ecology

What is an Ecosystem? Ecosystem A term used to describe the relationships between the many species living in a particular environment and between the living (biotic) and non-living (abiotic) components of this environment.

Frogs (as tadpoles and adults) occupy two different ECOSYSTEMS Eggs and Tadpoles Live in ponds (aquatic ecosystems) Adult Frogs Live in forests and grasslands (terrestrial ecosystems)

Model of an Ecosystem ECOSYSTEM ABIOTIC FACTORS BIOTIC FACTORS Non-living agents in an ecosystem e.g. water temperature, amount of light reaching pond floor, etc. BIOTIC FACTORS A factor in an ecosystem created by the presence and roles of other living things e.g. number of frogs, amount of algae, etc. Each part of the ecosystem is affected by other parts!

What is a Food Chain? Food Chain: Consumer Food Chain: A step by step linear sequence linking organisms that feed on each other. Starts with a food source such as plants (producers) and continues with animals and other living things that feed on plants and on each other (consumers). Consumer Consumer Consumer Producer

Producers can make their own food by taking energy from the Sun. Consumers are unable to create their own food, therefore they get energy by eating producers (plants) and/or other consumers (animals).

Frogs (as tadpoles and adults) occupy two different FOOD CHAINS Adult frogs are carnivores (feed on other animals) e.g. they eat insects Predatory birds (herons) prey on them (1) ADULT FROG – FOOD CHAIN Grass Insects Adult Frog Heron

Larger insects eat tadpoles Tadpoles are herbivores (feed on plants). They eat living algae and dead algae (an example of detritus – waste from dead plants and animals) Larger insects eat tadpoles (2) TADPOLE – FOOD CHAIN Algae (living) Tadpole Insects Fish or Dead Algae

Why should we care that frogs are dying? Because frogs and tadpoles are part of two different ecosystems and two different food chains, their decline affects many species, including us! A decline in the frogs results in an increase in the number of insects (e.g. mosquitoes). The more mosquitoes, the more malaria and hence, human death. This has already occurred in Bangladesh. A decline in the reproductive ability of frogs (e.g. from pesticides) leads to a decrease in number of tadpoles in the next generation. This increases the amount of algae (dead and living), thus increasing detritus above normal levels. A decline in the frogs results in a decrease in the number of species that eat frogs (e.g. snakes and herons)

Why are Frogs Dying? Loss of habitat (home) Poor Air and water quality Increasing ultraviolet radiation Climate change Increased stress on frogs’ immune systems Decreased resistance to disease Chytrid Fungus

1. Loss of Habitat We are destroying the water with pollution (e.g. pesticides, prescription drugs etc.) We are cutting down forests We are building highways and cities between the two ecosystems, increasing exposure to predators

2. Poor Air and Water Quality Frogs have thin, sensitive skin. Frogs breathe through their skin and by their lungs. Acid rain and pesticides can therefore go through their skin easily. This affects their ability to reproduce

3. Ultraviolet Radiation Their thin skin is also susceptible to UV radiation. The damage to the ozone layer (protective layer of atmosphere surrounding the Earth) caused by pollution increases the amount of UV waves that reach the surface of the Earth. This causes cell damage in both frogs and humans.

4. Climate Change Human activities are causing changes in the climate. Increase use of fossil fuels (coal, oil, gas) Increased global temperatures means less water available.

To Do Fill in missing definitions and examples from Sections 1.1 and 1.5 from your text. Complete “You and Food Chains” Activity.

Pictures from: http://picture-book.com/node/7029 http://www.seppo.net/e/amphibian-ark-an-international-frog-rescue-effort www.edupic.net/sci_gr.htm http://allaboutfrogs.org/info/doctor/sicky.gif