1. Ch. 1: “Watersheds and Wetlands”
Lesson 1.3: “Stream Biology”

2. Introduction
Streams and rivers are aquatic ecosystems that are often teeming with life. In addition to mosses, grasses, ferns, and other plants found in and along streams and rivers, there are three dominant groups of organisms in most stream communities. These include (1) algae and other protists, (2) invertebrates, and (3) vertebrates.

3. 1. “Stream Biology” Algae and Other Protists:
Algae are plantlike protists.
Algae can make their own food, therefore, they are known as producers or autotrophs.
Because they make their own food, algae form the base of most food chains.
Animal-like protists include ciliates, flagellates, and amoebae.

4. Algae

5. Food Chain

6. Ciliates

7. Flagellates

8. Amoebas

9. 1. “Stream Biology” Invertebrates:
List the most common types of freshwater invertebrates:
1. insects
2. mollusks
3. worms
Most of these aquatic invertebrates feed on algae and plants, and thus they are primary consumers.

10. Insects

11. Mollusks

12. Worms

13. 1. “Stream Biology” Vertebrates: Examples of amphibians:
1. salamanders 3. newts
2. frogs 4. toads
Examples of fish:
1. Fish that are primary consumers are called grazers, strainers, or suckers depending on how they feed.
2. pike, pickerel, gars, and bullheads examples of predatory fish.
3. The third group of fish are known as detritovores.

14. Salamanders, Frogs, Newts & Toads

15. Pike, Pickerel, Gar & Bullhead

16. 2. “Factors That Affect Freshwater Ecosystems”
Define biotic factor: living component of an ecosystem
Define abiotic factor: nonliving physical and chemical parts of an ecosystem

17. 2. “Factors That Affect Freshwater Ecosystems”
List examples of abiotic factors and describe/explain the effects each one has on the stream and on specific organisms living there:
1. stream order
2. temperature
3. current and velocity
4. substrate
5. sunlight

18. 2. “Factors That Affect Freshwater Ecosystems”
List examples of abiotic factors and describe/explain the effects each one has on the stream and on specific organisms living there:
6. turbidity
7. dissolved solids
8. dissolved gases:
oxygen
carbon dioxide
9. organic matter
10. pH

19. 3. “The Upper Perkiomen Creek”
List the dominant trees:
1. American beeches
2. red oaks
3. white oaks
4. black walnuts
5. river birches
6. sycamores
7. willows

20. 3. “The Upper Perkiomen Creek”
Animals:
1. gray foxes
2. moles
3. rabbits
4. blue jays
5. scarlet tanagers
6. pileated woodpeckers
7. gray squirrels
8. bats
9. coyotes
10. white-tailed deer

21. 3. “The Upper Perkiomen Creek”
Small vegetation:
1. Tussock sedge
2. ferns
3. skunk cabbage

22. 3. “The Upper Perkiomen Creek”
Aquatic invertebrates:
1. caddis flies
2. stoneflies
3. mayflies
4. mussels
5. snails
6. crayfish

23. 3. “The Upper Perkiomen Creek”
Terrestrial invertebrates:
1. ants
2. beetles
3. butterflies
4. bees
5. wasps
6. mosquitoes

24. 3. “The Upper Perkiomen Creek”
Fish:
1. dace
2. darters
3. minnows
4. suckers
5. brown trout
6. native brook trout

25. 3. “The Upper Perkiomen Creek”
Amphibians:
1. frogs
2. toads
3. salamanders

26. 3. “The Upper Perkiomen Creek”
Reptiles:
1. turtles
2. snakes