Exam Guide || With Complete Questions
& Answers (Graded A+)
Describe the general growth habits of, means of dispersal, and potential problems
caused by: Free-floating and rooted floating-leaved aquatic plants - ANSWER - Growth
habits: plants whose leaves float on the water surface (i.e. water lilies)
Dispersal: Free-floating- wind; Rooted- wind
Problems:
Free-floating - i.e lesser duckweed; form green blanket up to 2" thick on water surface;
difficult to control in large bodies of water.
Rooted - examples: water lilies, spatterdock, American lotus, and watershield. These
plants provide valuable cover for fish and are rarely a problem
Describe the general growth habits of, means of dispersal, and potential problems
caused by: Free-floating, filamentous, and "rooted" algae. - ANSWER - Growth habits:
can be found floating or attached to submerged surfaces in lakes, ponds, and streams.
Multiply rapidly through summertime.
Dispersal:
Free-floating - multiply rapidly suspended in the water
Filamentous - anchor to a submerged surface to multiply
Rooted - i.e. Chara and Nitella; attached to the bottom
Problems:
Free-floating - bacteria that decompose dead algae often use up the dissolved oxygen
in the water and produce fish kills. As they die, the algae also may release into the
water extremely toxic compounds that make the water unsafe to drink.
Filamentous - they may break loose and float as a mass over an entire body of water.
Rooted - sometimes difficult to control, and is often best to leave alone
List the advantages and disadvantages of chemical control of aquatic plants. -
ANSWER - Advantages-
Longer lasting control than mechanical methods, less labor, less cost, target specific
nuisance species
Disadvantage-
Restrictions on water use, oxygen depletion, too much nutrients can fuel other problems
with plants, inherent risk to people and nontarget organisms
Describe the beneficial roles of Wisconsin's fish populations - ANSWER - - Maintain
balanced communities by feeding on aquatic plants, insects, and other fish
- Providing a food source for natural predators
,- Fishing for food and sport is very popular in Wisconsin
- Fish farms and hatcheries raise fish for food, feed, fertilizer, bait, and for release into
state waters
List five types of situations in which fish control may be warranted. - ANSWER - -
Eliminating undesirable or competing fish from fish rearing ponds
- Removing exotic (non-native) or other undesirable species from a body of water
- Thinning stunted fish to bring a fish population into balance
- Eliminating fish from a hatchery water supply to prevent a potential reservoir of
disease-causing organisms
- Treating fish spawning sites to prevent overpopulation of an individual species
Explain why post-treatment management can be important in the long-term success of a
pesticide treatment project. - ANSWER - Some chemical treatments have failed not
because of unsatisfactory removal of the fish populations, but because of inadequate
planning and management after treatment.
List the two main reasons why mosquito control may be warranted. - ANSWER - -
Population
-Disease
Describe the four stages of the mosquito life cycle, including the main structural features
of each. - ANSWER - Egg
-generally 1/25 of an inch long
-oblong in shape
-most hatch within three days
-some have lateral extensions that serve as floats; others have spines that trap air to
float.
-numerous species glue eggs together to form a floating raft
Larvae
-head, thorax, abdomen
-head bears the antennae, eyes, and mouthparts
-the 8th segment of the cylindrical abdomen bears the respiratory apparatus
Pupae
-comma shaped
-lasts only a few days
-cephalothorax contains a pair of respiratory structures called trumpets
-abdomen contains a pair of paddle-like structures
Adult
-slender abdomen
-one pair of narrow wings, three pairs of long, slender legs
-elongated proboscis
-head bears a large pair of compound eyes, a pair of antennae, and a large proboscis
, -hairs on the antennae are short and sparse in females and long and bushy in males
-thorax contains three segments and bears the wings and legs
-long, cylindrical abdomen is comprised of ten segments; the ninth and tenth segments
are modified for reproduction in both sexes
List the roles plants play in the healthy aquatic ecosystem - ANSWER - - Producing
oxygen for other organisms in the lake
- Preventing shoreline erosion
- Lessening excess nutrients during the growing season
- Providing food and habitat for fish, waterfowl, and other aquatic animals
List ways that excessive plant growth can adversely affect the ecology and uses of a
water body. - ANSWER - - Harm the ecology of an aquatic ecosystem
- Curtail or prevent recreational water uses
- Impart tastes or odors to drinking water supplies
- Hamper water treatment operations
- Adversely affect aesthetics, resort trade, and waterfront property values
- Produce toxins that harm animals who drink water
Describe the general growth habits of, means of dispersal, and potential problems
caused by: Emergent Aquatic Plants - ANSWER - Growth habits: rooted in relatively
shallow water so most of their growth extends above the water line, or they grow in
water-saturated soils.
Dispersal: spread by an underground root system and new emergent plants can occur
almost anywhere in the network. Examples: cattails, arrowhead, bulrushes, and purple
loosestrife.
Problems: Dense and can limit recreational boating, fishing and swimming, however
they provide habitat for wildlife and shouldn't be controlled except in the case of purple
loosestrife.
Describe the general growth habits of, means of dispersal, and potential problems
caused by: Submergent Aquatic Plants - ANSWER - Growth habits: rooted plants with
all of their growth occurring below the water line (i.e. pondweeds)
Dispersal:
Pondweeds - extensive root systems and runners, new growth sprouts from roots,
runners and seeds; some have floating leaves and some submerged leaves that are
attached to center stem in alternate arrangement.
Whorled leaves - 3 or more leaves attached at one point on the main stem i.e. coontail,
water milfoil, and elodea are most common.
Problems:
Pondweeds - not usually a nuisance except for curly leaf pondweed and sago
pondweed. Many pondweeds are good habitat for wildlife and if removed can cause
aggressive nuisance plants to infest the area.