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DVFS - 7th Grade Watershed Study

Wil Franklin's picture


Digital Photos of Macroinvertebrates sampled by Delaware Valley Friends School seventh grade science class on September 28, 2008 from Rhoads Pond and Mill Creek, Bryn Mawr, Pennsylvania.


Ongoing Research:

Students should research one organism below (it may or may not be the one you photographed yourself).  In the blog section below, post information on the life cycle of your organism and identify with the name given next to the photograph.  In addition to life cycle facts, you may report on eating habits, prefered habitat, and unique or interesting behaviors.

dvfs 1 Caddisfly larva - dvfs 1

dvfs 2 Flatworm/Planarian - dvfs 2

dvfs 3Damselfly larva - dvfs 3

dvfs 4Aquatic Earthworm/ Oligochaeta - dvfs 4

dvfs 5Dragonfly larva - dvfs 5

dvfs 6Leeches/Hirudiae - dvfs 6

dvfs 7 unidentified - dvfs 7

dvfs 8Snail egg mass - dvfs 8

dvfs 9Damselfly - dvfs 9

whatsthatbug Caddisfly larva f/




Fisher man's picture

Damselflies undergo incomplete metamorphosis

Damselflies undergo incomplete metamorphosis, with an aquatic nymph stage. The female lays eggs in water, sometimes in underwater vegetation, or high in trees in bromeliads and other water-filled cavities. Nymphs are carnivorous, feeding on daphnia, mosquito larvae, and various other small aquatic organisms. The gills of damselfly nymphs are large and external, resembling three fins at the end of the abdomen. After moulting several times, the winged adult emerges and eats flies, mosquitoes, and other small insects. Some of the larger tropical species are known to feed on spiders, hovering near the web and plucking the spider from its nest.

Anonymous's picture

Life Cycles There are three

Life Cycles
There are three stages of Damselflies. First they are eggs that are laid in water. The eggs usually hatch between one or two weeks. After hatching from the egg, the larvae, also called a nymph lives in water as an aquatic predator. Damselflies live for two months to three years as nymphs. Then the nymph begins to develop some of the features that will prepare it for life as an adult, such as expanded eyes, flight muscles and wings.

Eating Habits
Damselflies will eat nearly anything they can successfully catch and ingest. They mostly eat aerial prey, like flies, and they catch it by forming a basket with it three pairs of legs and scoop it out of the air.

Damselflies depend of fresh water for egg laying, but they can live in different places, from small pools, to water falls.

Interesting Facts
Fishermen like using them for fishing lures because fish like to eat them.

Anonymous's picture

1. Life cycle: The leech

1. Life cycle: The leech life cycle starts from egg cocoon to young to adult.

2. Eating habits: All leech species are carnivorous. Some leeches are predatory and feed on worms, snails, and insect larva.

3. Habitats: Hirudie leeches live in ponds.

4. Interesting behaviors: Leeches are used for reattaching body parts that have been taken off. Hospitals use to use leeches for this.

Anonymous's picture

Life Cycle A flatworm

Life Cycle
A flatworm reproduces by splitting into two. When a flatworm is split up it immediately forms a new flat worm.

Eating Habits
A flatworm takes food in and gets rid of wastes through the same opening. It eats small worms, insects and microscopic matter.

They avoid light and they are found under rocks and trash during the day. They are also found in, fresh water ponds lakes ditches rivers and streams.

A flatworm has no skeleton. It has tiny bristles called cilia that help it move it also has two layers of muscles under its skin. It has three cell layers and two nerve cords running down either side. The flatworm has two brains. It has two eyespots that help it sense light. The flat worm is 5 to 30 mm long.

Anonymous's picture

The aquatic earthworm is a

The aquatic earthworm is a worm that lives in water in muddy and sandy places. An aquatic earthworm is usually 1/4 “ to 5 inches, it has a smooth coat, no legs and both male and female aquatic earthworm can lay eggs. The aquatic earthworm eats bacteria, algae, diatoms, decaying, tree wood and leaves. It was difficult to find the life an aquatic earthworm.