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Science Unit B > Unit C Section 2.1 > Flashcards

Unit C Section 2.1 Flashcards

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Biology 101 flashcards
1
Q

What is a ozone layer?

A
  • Ozone (O3(g)) forms a layer that shields Earth from much of the damaging ultraviolet (UV) radiation from the Sun.
  • The ozone layer is 15 to 50 km above Earth’s surface,
  • but ozone also exists at ground level and can be harmful.
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2
Q

What is the meaning of monitoring?

A

Monitoring means keeping track of something for a specific purpose

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3
Q

Can clarity be a good indicator of clean water?

A
  • Clarity is not a good indicator of water quality.
  • Clearwater can sometimes be harmful to humans and other organisms.
  • For example, lakes affected by acid rain are crystal clear and lifeless.
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4
Q

Water quality is determined according to:

A

Water quality is determined according to what the water is used for

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5
Q

Both provincial and federal governments set guidelines for water quality in five categories of water use:

A
  • human drinking water
  • recreation such as swimming
  • livestock drinking water
  • irrigation
  • protection of aquatic life
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6
Q

How do scientists monitor water quality:

A

by biological and chemical indicators

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7
Q

BIOLOGICAL INDICATORS:

A

Scientists use organisms that live in water to help determine water quality.

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8
Q

What are the organisms that are used as biological indicators:

A

These indicator organisms include fish, plants, worms, insects, plankton (microscopic algae and tiny animals), protozoa, bacteria, and viruses.

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9
Q

What are Microbiological Indicators:

A
  • Microscopic organisms such as bacteria can cause serious health problems if they are present in large enough numbers.
  • Too many microscopic organisms such as bacteria is an indicator of bad water quality.
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10
Q

What are Invertebrates:

A

Invertebrates are animals without backbones

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11
Q

Why are invertebrates used as indications for water?

A

They are used for monitoring because different invertebrates prefer different living conditions.

Water temperature and pH can also affect the types of
organisms found in an area.

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12
Q

Invertebrate examples:

A

insects, crustaceans (such as shrimp), worms, and mollusks (such as clams)

  • water boatman
  • mosquito larva
  • water strider
  • flatworm
  • leech
  • midge larva
  • mayfly nymph
  • clam
  • caddisfly larva
  • dragonfly nymph
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13
Q

How much should the pH of water be to see less fish?

A

If the pH of the water in an aquatic environment is below 5.0, you will not find many fish there, especially young ones.

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14
Q

Which insects are good indicators for acidic environments?

A

Some insects such as mayflies are also very sensitive to acidic environments and environments that have
little dissolved oxygen

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15
Q

The diversity of all organisms decreases……….

A

as acidity increases and dissolved oxygen decreases

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16
Q

What is an indicator for little dissolved oxygen?

A

few insects and many worms may mean that the water contains little dissolved oxygen.

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17
Q

What is an indicator of good water quality?

A

A pond that supports a wide variety of organisms probably has good water quality for allowing organisms to survive

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18
Q

Is a pond with indicators for good water quality safe for humans?

A

it cannot be considered safe for humans to drink until it is tested to make sure.

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19
Q

Is water only made up of H2O?

A

Pure water is made up of only H2O(l) molecules, but water in the environment is never completely pure.

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20
Q

The concentration of what affects water quality?

A

Water can contain many different

organic and inorganic compounds

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21
Q

The most commonly monitored as

indicators of water quality:

A
  • dissolved oxygen
  • plant nutrients such as nitrogen and phosphorus
  • acidity
  • pesticides
  • heavy metals
  • salts such as sodium chloride and magnesium sulfate
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22
Q

What are parts per million?

A

The concentration of chemicals in the environment is usually measured in parts per million (ppm)

or milligrams per liter

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23
Q

How is parts per million calculated?

A

One part per million means that one unit of an element or chemical can be found in one million units of solution.

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24
Q

How are parts per million calculated?

A

One part per million means that one unit of an element or chemical can be found in one million units of solution.

25
Q

How is oxygen dissolved into water

A

As the water churns over and around rocks, oxygen from the air is dissolving into it

26
Q

The level of dissolved oxygen in water depends on:

A
  • temperature
  • turbulence due to wind or the speed of moving water
  • the amount of photosynthesis by plants and algae in the water
  • the number of organisms using up the oxygen
27
Q

Which amount of ppm is able to support most organisms that live in lakes and streams.

A

Five milligrams per liter (equal to 5 ppm) of dissolved oxygen

28
Q

2 ppm of dissolved oxygen is able to support which invertebrates?

A

Midge larvae and some worms can survive

29
Q

4 ppm of dissolved oxygen is able to support which invertebrates?

A

Freshwater shrimp, midge larvae, and worms can survive

30
Q

6 ppm of dissolved oxygen is able to support which invertebrates?

A

Mayflies, stoneflies, and beetles begin to disappear

31
Q

8 ppm of dissolved oxygen is able to support which invertebrates?

A

Large numbers of diverse invertebrates

32
Q

What types of rivers have better excess to air?

A

Rapids expose more water surface to the air than smooth river flow does.

33
Q

What is one factor that can affect dissolved oxygen?

A

One factor that can affect dissolved oxygen is an increase in phosphorus and nitrogen in the water.

34
Q

How can phosphorous and nitrogen get into the water?

A
  • Sewage outfalls (acidic rain or snow falls)

- runoff from fertilized fields

35
Q

How can phosphorous and nitrogen affect the oxygen in water?

A
  • Higher concentrations of these nutrients in water cause increased growth of algae and green plants
  • As more algae and plants grow, more die.
  • This dead organic matter becomes food for bacteria that decompose it.
  • With more food available, the bacteria increase in number and use up the dissolved oxygen in the water.
  • When the dissolved oxygen content decreases, many fish and aquatic insects cannot survive.
36
Q

In which types of water can magnesium phosphate combine?

A

Basic water

37
Q

what effect does magnesium phosphate have on water?

A

Magnesium phosphate does not dissolve in water so it forms a precipitate, causing the water to appear cloudy

38
Q

What is the pH of normal rain and snow?

A

5.6 because carbon dioxide from the air dissolved in them to form weak carbonic acid

39
Q

How can precipitation be considered acid snow or rain?

A

Precipitation with a pH lower than 5.6 is considered acid rain or snow

40
Q

At what ph of water will most fish start to disappear?

A

Most fish disappear if the water’s pH falls to 4.5.

41
Q

In the Canadian shield, what is not able to neutralize the acid?

A

The thin soils and the chemical composition of the rocks

42
Q

What is spring acid shock?

A

acidic deposits build up in ice and snow in the winter. In spring, when the ice and snowmelt, the acid meltwater flows into aquatic systems. This quickly creates a concentration of acid that can dramatically lower the pH of the water in a pond, slough, lake, or river for a short period of time.

43
Q

How can spring acid shock affect aquatic life?

A

It can seriously affect the eggs of aquatic organisms, as well as the young offspring of spring-spawning fish.

44
Q

What is the disadvantage of pesticides?

A

-Some pesticides have had longer-term harmful effects because they remained in the environment after they were no longer needed.

-even these shorter-lasting pesticides may cause pesticide-resistant pests to develop.
-insects reproduce rapidly, so many generations can be exposed to an insecticide in one season.
-new insecticides must be developed
-shorter-lasting pesticides may not disappear entirely
from the environment.

45
Q

Scientists are finding that water samples may contain
very low concentrations of many different pesticides

How is this a problem?

A

One pesticide at a very low concentration might not be harmful. However, several pesticides together might mix to form a much more toxic or poisonous substance.

46
Q

Toxicity:

A

Toxicity describes how poisonous a

substance is.

47
Q

What are toxins?

A

Toxins or poisons are substances that produce serious health problems or death when introduced into an organism

48
Q

In order to compare toxins, scientists use a measurement called

A

LD50

49
Q

What does LD50 stand for?

A

“LD” stands for “lethal dose”

and the “50” represents 50%

50
Q

How is LD50 used?

A

LD50 is the amount of a substance that causes 50% of a group of test animals to die if they are given a specified dose of the substance all at once.

51
Q

Why is LD50 used?

A

LD50 testing allows scientists to compare toxicity

because they are comparing the dosage that will produce the same outcome: death.

52
Q

What animals is LD50 usually used on?

And on which body part?

A

LD50 testing is usually done on rats and mice.
the usual ways are by mouth or applied to the skin

the more toxic the substance is, the lower its LD50 number is.

53
Q

Why are some metals called heavy metals?

A
  • They are called heavy metals because they have a density of 5 g/cm3 or more
  • This means they are five or more times heavier than an equal volume of water
54
Q

Examples of heavy metals:

A

copper, lead, zinc, mercury, cadmium, and

nickel.

55
Q

Where do heavy metals occur?

A

These metals occur naturally in rocks, soil, and sometimes in water.

56
Q

Why do water quality monitoring includes checking concentrations of heavy metals?

A

Heavy metals can be toxic to a wide range of organisms, including humans

57
Q

How are heavy metals found in water?

A

acidic water can dissolve lead in pipes.

Cadmium is present in some fertilizers as an impurity.

Plants growing in basic soils are able to take in this cadmium

58
Q

How are heavy metals harmful?

A
  • high levels of heavy metals over long periods, they may experience serious health problems.
  • It can affect normal development and cause permanent brain damage or even death

Science Unit B (61 decks)

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