Biol 2306 Final Exam At Acc

Front 1

What causes zonation?

Back 1

Principal factor is temperature, latitude , and wind

Front 2

As you increase in altitude, temperature becomes

Back 2

colder

Front 3

How does latitude effect zonation?

Back 3

If you compare a mountain in the tropics to a mountain in Colorado, you will have to go to higher altitudes in the tropics to reach the same conditions of cold. As a result, the comparable life zones are found at different altitudes.

Front 4

How does wind affect zonation?

Back 4

Wind can have a major impact upon plant life. Generally, winds are stronger at higher altitudes. Plants that live on high mountain
peaks are buffeted by strong winds, especially when they are not insulated by snow.
These plants generally are small and hug the ground, which exposes less of the plant body to the wind.

Front 5

What are the 5 distinct life zones of the Himalayas?

Back 5

(1) lower reaches of the deep valley. The climate is warm, humid and tropical. There
is lush vegetation of many species, including bamboo and many rhododendron trees. Animals are numerous, including tigers, rhinoceros and many birds. Watch the tape for descriptions of the animals found here: langur monkeys, ring-necked parakeets and pheasants.

(2) 1000 meters - rhododendron trees dominate. The air is still moist but the temperature is cooler, with many warm days and cold nights. Night frosts are common. Watch the tape for descriptions of the organisms found in the cooler forests: orchids, moss, close-packed flowering plants, Himalayan panda, musk deer.

(3) 2500 to 3300 meters - coniferous forests of Himalayan fir and Bhutan pines. Animals on the tape include yellow-throated marten, Himalayan bear, ants, insects and rodents.

(4) 3300 to 4400 meters - shrubs, grasses and small cushioned flowering plants. Watch the tape for the animals who live here - bearded vultures, snowcocks, tahrs and choughs.

(5) 4400 to 5400 meters - lichens.

Above this altitude (5400 meters), there is no vegetation. The ground is covered with snow and ice.

Front 6

Symbiosis refers to

Back 6

a very close relationship between two different organisms.
- "Symbiosis" translates to "living together."
- use symbiosis to represent a relationship which 1) is required by atleast one partner in order to survive or reproduce and 2) benefits at least one partner

Front 7

What are the 3 kinds of symbiosis?

Back 7

1. mutualism- when both partners benefit
2. commensalism- one partner benefits and the other gets no apparent benefit nor is harmed.
3. paratism- one partner (the parasite) benefits from the relationship while the other (the host) is harmed

Front 8

How is a lichen formed?

Back 8

by an association between one kind of algae and one fungus

Front 9

Is a lichen mutualistic or parasitic?

Back 9

a lichen can be mutualistic at one time and parasitic at another time.

Front 10

Why is the lichen a very important organism in many ecosystems?

Back 10

Since the fungus can break down bare surfaces, such as rock or wood, the lichen is able to colonize surfaces that other organisms cannot. The algae provide the food while the lichen breaks down the substrate. As a result the surface is changed, often providing oppurtunities for plants to move into the area.

In very harsh environments, such as mountain peaks, polar regions and bare rock surfaces, lichens become very important sources of food. Reindeer moss (which is a type of lichen) is even able to grow on the soils of tundra and northern coniferous forests.
-Lichens are able to absorb nutrients which are dissolved in rain and dew. B/c of this they are very sensitive to air pollution. especially heavy metals and acid rain.

Front 11

What are hydrothermal vents?

Back 11

are deep-sea springs that release water that has been heated to very high temperatures by underwater volcanoes.

In the process, the heated water picks up large amounts of sulfides. When it comes out of the hydrothermal vent, the sulfides are released into the cold deep-sea waters.

Front 12

When were hydrothermal vents discovered?

Back 12

1977 by scientists examining the volcanic ridges of the Pacific Ocean floor, near the Galapagos Islands.

Front 13

What organisms do you find living near the hydrothermal vents?

Back 13

The sulfides are used by chemosynthetic bacteria that use the energy from sulfides to produce their own food. Giant tube worms contain bacteria in their tissues, apparently living in a symbiotic relationship. The tube worm receives food from the bacteria living in its body. In exchange, the tube worm concentrates sulfides in its blood, which are then delivered to the bacteria for processing. Other organisms- mussels, giant clams and polychaete worms- filter bacteria from the water

Front 14

Describe the relationship between termites, flagellates and bacteria, including the benefit to each species in the relationship.

Back 14

The termite cannot digest the cellulose in wood. The termite must have living one-celled organisms called flagellates in its gut to digest cellulose. The termite provides the flagellates with wood; the flagellates provide the termites with food. Seems like a clear-cut relationship, doesn't it? Further study has shown that the flagellates contain bacteria inside their bodies; it is the bacteria inside the flagellate that actually digest the cellulose. So, this is a mutualistic relationship between three species: termites, flagellates and bacteria. Everybody wins.

Front 15

Where, besides hydrothermal vents, have chemosynthetic bacteria been found?

Back 15

other enclosed ecosystems (caves) have been discovered that are also based on chemosynthetic bacteria.

Front 16

Describe and compare the two polar regions with respect to types of ice and presence or absence of lang.

Back 16

Antarctica is the huge polar continent of the Southern Hemisphere. It is surrounded by a permanent ice pack and the land is permanently buried by a mile or so of glacier ice. The Arctic Ocean is the ocean that covers the North Pole, which has a permanent ice pack on its surface.

Front 17

Compare the locations of arctic and alpine tundra.

Back 17

Arctic tundra occurs on the northernmost lands of North America and Eurasia.

Alpine tundra occurs high on the mountains, but not necessarily on top of the mountain

Front 18

Describe the two main problems for organisms living in extremely cold places.

Back 18

Extreme cold kills cells. When liquid water inside a cell freezes and ice crystals form, the cell membrane and/or cell walls rupture as the ice crystals expand, killing the cells.

Extreme cold also slows down vital biochemical reactions.

Front 19

Compare ectotherms and endotherms. Describe the advantages or disadvantages of being an ectotherm or an endotherm living in a cold climate.

Back 19

In many animals such as lizrds and insects, body temperature is controlled in part by the temperature of the envionment and in part by behavior. These animals are called ectotherms.

Birds and mammals have a different approach to solving these same problems. They do not rely on the sun to heat them up. They generate their own body heat by burning lots of fuel inside their cells. These animals are called endotherms.

Front 20

Describe the various adaptations to cold that are used mostly by endotherms.

Back 20

-Insulations is used to trap as much of their body heat next to the surface of their skin.
-fur is used as insulation. Outer layer consists of guard hairs, usually long and coarse. The inner layer, the undercoat, consists of a thick layer of fine wooly hairs.
- Birds use feathers as insulations. Outer layer consists of contour feathers Down feathers have a short quill with fluffy tufts that excel at trapping air.
- Blubber is a thick layer of fat underneath the skin that forms a blanket trapping heat within the body.
-There is also body size, coloration, hibernation and camouflage

Front 21

Compare the animal life of the Arctic and the Antarctic.

Back 21

In Antarctica, there are no large terrestrial predators. Once animals such as seals and penguins are on the land, they are relatively safe from predators.
-The Arctic region does have large terrestrial predators such as the polar bear and the arctic fox. Animals can migrate to and from this area

Front 22

What is a polar region?

Back 22

areas where surface ice and snow remain frozen all year around.

Front 23

What is a tundra?

Back 23

is found in areas where the climate is warm enough in summer to melt surface ice and snow and thaw a few inches of the soil. A permanently frozen layer (the permafrost) is located beneath the surface of the soil.

Front 24

What is metabolic rate?

Back 24

the rate at which the animal burns fuel

Front 25

Intro.
What is the difference between latitude and longitude?

Back 25

latitude are unites from north-south measurement around the earth. These are horizontal lines that go around the earth. The location is always given as latitude first, then longitude

Longitude are units of east-west measurement around the earth. These are the vertical lines.

Front 26

What is the difference between the earth's revolution and the earth's rotation?

Back 26

revolution is the movement of the earth around the sun

rotation is the movement of the earth on its axis

Front 27

What is the difference between an ocean and a sea?

Back 27

Ocean is a large body of salt water (5 oceans: Atlantic Antarctic, Arctic, Indian, Pacific)

Sea-usually refers to a body of salt water, smaller than and often more shallow than an ocean (examples: Baltic, Caribbean, Mediterranean)

Front 28

Define and describe the concept of a species tolerance zone. Differentiate between the optimal range, stress zones, tolerance limits and lethal zones.

Back 28

Each species on the earth has a range of physical conditions with in which they can survive that can be called their tolerance zone.

A. optimal range- range of physical factor within which most individuals survive
B. stress zones- zones at ends of optimal range in which very few individuals survive
C. tolerance limits- upper and lower limits beyond which no individuals survive
D. zones outside of tolerance limits where no individuals survive

Front 29

Define Limiting factor. Compare and contrast the limiting factor of terrestrial organisms with those of aquatic organisms.

Back 29

A limiting factor is any condition or factor that exceeds an organism's tolerance range.

For terrestrial organisms (species that live on land), the limiting factors are usually climate (temperature and precipitation), light, soil structure and nutrients.

Aquatic organisms (those that live in the water) are limited by salinity, temperature, current, pH, dissolved oxygen, light, and water nutrient leve.

Front 30

Compare and Contrast biotic and abiotic factors. Give examples.

Back 30

The physical characteristics of an organism's environment (temperature, pH, light, etc.) are called abiotic factors. But the environment also contains biotic (living) components. The biotic components include all living organisms found in a particular region.

Front 31

Compare and contrast producers, herbivores, predators and decomposers. Give examples.

Back 31

-Bacteria and fungi are decomposers, responsible for breaking down urine, feces, dead wood, fallen leaves, and carcasses into their smallest components. This process returns nutrients (such as carbon, oxygen, iron, nitrogen, potassium) to the environment so the nutrients can be reused.
-Producers include plants, cyanobacteria, algae and other organisms that carry out photosynthesis, using water, carbon dioxide and the energy of sunlight to produce food
-herbivores are animals that get their food by directly eating the photosynthesizers.
-predators eat herbivores

Front 32

Explain two main components of climate that influence species distribution. Explain how they vary with latitude and altitude.

Back 32

-affected by temperature and precipitation.
-effect of latitude on Temperature
as you move north or south away from the equator, two things happen to make the temp. decrease:
1. solar radiation is spread over a large area due to angle of incidence of solar radiation
2. solar radiation has to pass through more or the atmosphere before it hits the earth's surface

-effect of altitude on temperature
-as you move up from mean sea level, the temp generally decreases. This is because as you go higher, the atmospheric pressure decreases, which means the air is less dense and that means that the molecules of the air cannot hold as much hear.

Precipitation is the amount of rain, snow, sleet or any water that falls from the sky.
-effect on latitude on precipitation
-at the equator the sun has its greatest effect and it heats up the air, which rises. It also evaporates water from the planet's surface into the air. As the air rises, it cools off. When it cools off, the moisture condenses into larger droplets of water and falls back onto the surface as rain. Therefore, areas close to the equator have high rainfall.

Front 33

Discuss the effect of ocean currents on climate.

Back 33

Ocean currents are defined as the movement of surface water caused by the rotation of the earth and the action of wind on the water. The currents affect air temperature in coastal more strongly than inland areas. The Gulf Stream is a current in the North Atlantic Ocean. It sweeps downward past Africa, then turns when it reaches the equator and moves westward towards South and Central America. Those land masses in turn deflect the current northwards along the eastern coast of the United States. From there it continues eastward across the Atlantic towards Europe, which deflects it southwards past the coast of Africa. It makes a big clockwise circle in the North Atlantic Ocean. As it flows along the equator, the water warms up. Later, when this warm water moves along the eastern coast of the U.S. and past Europe, it gives up some of the heat. The climates of the coastal areas that are passed by the Gulf Stream are much warmer and more mild than they would be expected to be based only on their latitude and altitude.

Front 34

Describe a rain shadow and its effects upon precipitation.

Back 34

Rain shadows exist in areas where mountain ranges block the prevailing winds coming inland from the ocean. For example, on the west coast of North America the wind is coming from the west across the Pacific Ocean. As air moves over the ocean it picks up evaporating water. Soon after this moist air reaches the mainland, it runs into mountain ranges. To get past the mountains, the air has to go over them. This cools the air, and a lot of the moisture in the air condenses and falls as rain on the windward side of the mountain range (windward means the side the wind is coming from). The air that gets over the mountains is very dry, and it usually causes dry conditions and even deserts on the leeward side of the mountains (leeward means the side away from the wind). Thus we have a lush temperate rain forest on the coast of Washington and Oregon, and farther inland on the other side of the mountains there are very dry conditions, almost like a desert.

Front 35

What is the role of wind in climate?

Back 35

Wind – the movement of air – is responsible for the redistribution of heat and moisture in the atmosphere, so it has an effect on climate also. Surface winds between the equator and 30 degrees latitude flow towards the equator. In the temperate zone (30 to 60 degrees) surface winds flow away from the equator. And in the polar zones they flow towards the equator again.

If this were the only factor affecting wind direction, most parts of the world would have northerly or southerly winds most of the time. There is another important force that alters the patterns caused by convection currents. It is called the Coriolis effect and it is caused by the earth's rotation acting on the northerly and southerly winds. It causes surface winds going south to be deflected slightly to the west, and surface winds going north to be deflected towards the east.

Front 36

Why are soil characteristics important in determining the distribution of animals?

Back 36

The effect is indirect: plant species only grow in areas where both climate and soil conditions are appropriate. Because animals need plants for food and sometimes shelter, animal distribution depends on plant distribution. So both plants and animals are affected by soil conditions.

Front 37

Discuss the roles nutrients, particle size and shape, and organic content play in determining soil characteristics.

Back 37

-Nutrients are materials used for growth and maintenance in living things.
-Particle size and shape-the mineral component of soil comes in different sizes and shapes.
-organic content-organic material of soil consists of dead plants and animals and animal feces in various stages of decomposition. Organic material in the soil serves as an additional source of nutrients for plants and also adds to the water holding capacity of the soil.

Front 38

Describe plate tectonics and continental drift.

Back 38

The crust of the earth is not one solid mass, but is divided into sections called "plates." The crust sits on the mantle, which is made of molten (liquid) rock. The crust is much cooler than the mantle, so the molten rock that is next to the crust cools down and sinks down into the mantle. At the same time but in different places, hot molten rock from lower regions of the mantle rises towards the crust. If it cannot go through the crust, it is forced to flow underneath the crust and creates currents. Friction between the mantle and the crust moves the continental plates in the direction of these currents. This movement is called continental drift.

Front 39

What effects have tectonics and continental drift had on the distribution of species?

Back 39

a. closely related species that are found on different continents are usually there because those land masses were joined at some point in the past. As one species is broken into separate populations (such as being on different continents when the land masses separate), each population begins to change in different ways. If there is enough change, the populations will become new species. This is the basic concept of speciation by which most species are produced
b. isolated land masses often contain many unique species
c. species that depend on each other occur in the same areas. In some cases this is because of a symbiotic relationship. In other cases it may be because one species needs the other species for food or shelter.

Front 40

Which modern continents were part of:
Pangaea
Laurasia
Gondwana

Back 40

Pangaea- AKA the supercontinents included everything
Gondwana-South America, Africa India, Antarctica/ australiaS
Laurasia- North America, Eurasia

Front 41

Describe the concepts of evolution and natural selection.

Back 41

-evolution means genetic change over time
-natural selection is when organisms had many more offspring than actually survived to reproduce

Front 42

Describe the concept of evolutionary adaptation.

Back 42

An adaptation is any trait that allows an organism to be successful (to survive and reproduce) in a given environment

Front 43

Define Taxonomy and briefly explain why it is important.

Back 43

Taxonomy is the process of identifying and classifying species. It is used to group similar organisms based on shared characteristics, which become more specific as the groups get smaller. It assumes that similar organisms have properties in common and that similar organisms are closely related to each other. This way of organizing life is useful because if we know something about one member or a group, we should be able to apply that knowledge to other members of the same gropu.

Front 44

List the levels of taxonomic classification in correct order from the largest to smallest.

Back 44

Kingdom (Animalia), phylum (Chordata), class (Mammalia), order (Rodentia), family (Sciuridae), genus (Sciurus), species (Sciurus Niger)

Front 45

Define species. Give examples.

Back 45

the word species is generally used to represent a collection of similar organisms that are capable of interbreeding under natural conditions and producing fertile offspring. One example is the familiar fox squirrel (sciurus niger) Fox squirrels can breed with each other but do not breed with gray squirrels (sciurus carolinensis), which are different species.

Front 46

Unit 2
Explain deciduous trees and evergreens.

Back 46

-Deciduous trees loose all their leaves for part of the year, usually during the winter.
-Evergreen trees always have leaves

Front 47

What is the difference between conifers and broad-leaved trees?

Back 47

Conifers are usually evergreens that have leaves shaped like needles. The shape and structure of the needles are adaptations for dry conditions. The long thin shape of the needles decreases the amount of surface from which water can evaporate. The leaves have a thick waterproof layer called a rind that protects them from drying out. The leaves have holes through which gases enter and exit. These holes are sunken into pits, which reduces evaporation. Often live in areas with long cold winters when water is frozen and cannot be used by the trees.

Broad leaved trees produce their seeds inside flowers. More closely related to other flowering plants, such as daisies and roses, than to conifers. Typically their leaves are thin and broad, which means more light can strike the leaf (more photosynthesis). The reproductive cycle of a typical broad-leaved tree, such as an oak tree, is completed in a much shorter time than in conifers. Reproduce in months rather then years. Use animals to transfer pollen from flower to flower, but rely on the wind. Produce enormous amounts of pollen just like in conifers and for the same reasons.

Front 48

How are producers, primary consumers, secondary consumers, and tertiary consumers related to each other in terms of food chains?

Back 48

producer ->primary consumer secondary consumer -> tertiary consumer

Primary consumers eat living plants aka herbivores. Secondary consumers eat primary consumers. Tertiary consumers eat secondary consumers.

You can call them predators or carnivores.

Front 49

How are plants, herbivores, carnivores, omnivores, scavengers, and decomposers related to each other in terms of food chains?

Back 49

Omnivores consumes both plant material and other consumers.
Scavengers eat recently killed animals.
A decomposer breaks down long dead plant and animal matter (ex. fungi and bacteria).

Front 50

Describe the function of decomposers.

Back 50

are critical to an ecosystem b/c they return the nutrients that were "trapped" in the body of a plant or animal to the soil. Once in the soil, new producers can reincorporate them into living tissue or the nutrients can run off the soil into water where algae and water plants can use them.
Not usually included in a food chain or food web.

Front 51

Describe zonation in a typical temperate forest.

Back 51

Tallest trees for the canopy.
Beneath the canopy is a layer made up of the branches and leaves of smaller trees, the understory layer.
Below the understory lies the shrub layer, made up of woody plants that are too short to qualify as trees.
The shrub layer in its turn is taller than the ground layer, which consists of tender green herbs that are the shortest members of the forest community. The ground layer covers the forest floor.
The floor is made of soil covered by a layer of leaf litter.

Front 52

Describe the process of decomposition on the forest floor.

Back 52

Leaf litter is composed of dead leaves from all the plants that extend above the forest floor. As the leaf litter decomposes it is turned into humus that adds texture and nutrients to the soil. The texture of the soil is important because it determines how much space there is between soil particles and that determines the ability of plant roots to grow and obtain oxygen. The more space there is between soil particles, the easier it is for the roots to grow deeper into the soil, and more air can get into the soil for the roots to use. (We’re talking about soil humus, not a yummy Middle Eastern dish more commonly spelled as hummus.)

Front 53

Compare decomposition in temperate conifer and broad-leaf forests.

Back 53

The types of trees in the forest determine the nature of the soil, since they determine the nature of the leaf litter. Conifer needles make leaf litter that is acidic. The acidity of the leaves hampers decomposition, so the leaf litter builds up into a thick layer that makes it difficult for young plants to get established. The slow rate of decomposition also means that less humus is made. Because there is less humus, the soils are less rich in nutrients. Thus, these forests can support fewer species of plants and the understory, shrub and ground layer are less developed than they are in broad-leaved deciduous forests. The decomposers present in the soil are the food for many different kinds of soil invertebrates. Since coniferous forest soils have fewer decomposers, fewer soil invertebrates can live there.

In contrast, the thin leaves of broad-leaved deciduous trees are easily decomposed and do not acidify the soil. The leaf litter breaks down rapidly and a lot of humus is added to the soil. The soil is thus richer in these forests than in coniferous forests. With richer soil, more plants can grow and these forests have well-developed understory, shrub and ground layers. With many decomposers happily decomposing all that lovely leaf litter, there is an ample food supply for many different kinds of soil invertebrates.

Front 54

What are conifers? explain.
How is pollen spread?

Back 54

Conifers are cone-bearing trees. Their seeds develop inside cones instead of flowers.
Reproductive cycle of a typical conifer, such as a pine tree, takes two years to complete. During the first year both male and female cones are produced.
Males cones are very small and are grouped together in clusters. They produce enormous amounts of pollen. The female cones are larger than the male cones, but still smaller than mature female cones. They are soft, and the eggs are located within the cone, between the scales.
Wind is used to spread pollen.

Front 55

Describe the montane conifer and boreal conifer.

Back 55

Montane Coniferous Forest
- The coniferous forests extend south from the boreal forest along the major mountain ranges, such as the Rocky Mountains in Canada and the US, and to the Alps in Europe. In these areas, the forest is called the montane coniferous forest. Below the alpine vegetation is a region that looks similar to the boreal forest, although it contains different species of spruce and fir. At lower elevations, the number of conifer and other plant species (aspen, pine) increases, so the lower montane coniferous forests are more diverse than the boreal forest. The increase in diversity is due to a less rigorous climate and to the longer growing season in these more southern regions.

Boreal Coniferous Forest
-Most of the coniferous forests belong in this category, also called northern coniferous forests or the taiga. This type of forest is found south of the Arctic tundra throughout North
America and Eurasia. The climate is always cold and is wet during the short summers which last really for only 1 to 3 months. Of all the forest types, the northern coniferous forest has the lowest diversity, and consists mostly of large, monotonous expanses of spruces and firs.

Front 56

Describe the temperate rain forest and pine savanna.

Back 56

Temperate Rain Forest
- Along the west coast of Alaska and British Columbia, extending down into Washington, Oregon, and northern California, is a very special kind of coniferous forest, the temperate rain forest (also called the north coast temperate coniferous forest). This region experiences high rainfall (200-300 cm per year) and cool, but rarely cold, temperatures (2-20 degrees C). Because of the abundant rainfall and relatively mild climate, the trees here grow to be giants. The canopy trees are commonly 50-75 m tall. In the redwood groves of California, the trees grow to 100 m and are over 2000 years old. Look for redwoods in the video.

Pine Savanna
-On the coastal plain of the Carolinas, Georgia and Florida, the vegetation consists of pine trees scattered over a wide area of grassland. The trees do not grow close enough together to form a closed canopy, and that lets in enough light for the grasses to grow luxuriously. This type of vegetation is called pine savanna. Pine savannas are maintained by fire. Broad-leaved tree seedlings are quickly destroyed by fire. But pine seedlings and grasses are protected from the fire by their structure. The growing buds of pines are protected within tufts of leaves. The growing points of the grasses are below the ground. Without fires, the broad-leaved trees would invade and eventually shade out the pines and grasses, turning this area into a deciduous forest. The fires are usually caused by lightning.

Front 57

Describe the general location of tropical rain forests and the climatic conditions that exist where these forests are found.

Back 57

Tropical rain forest, often called the jungle are located around the equator (between 10 degrees latitude north and south). The tropical rain forests are found in regions that are warm year around and receive large amounts of rain, often on a daily basis

Front 58

Describe the temperate deciduous forest.

Back 58

Temperate Deciduous Forest
The temperate deciduous forests of the Northern Hemisphere once covered
northeastern North America, most of Europe, and northeastern China and the Korean peninsula. Both deciduous broad-leaved trees and conifers can be found in these forests, although they are dominated by the broad-leaved trees. The tree species that make up the greatest proportion of plants in the forest differs in different areas. For example, in the northeastern United States, the deciduous forest is dominated by maple and beech trees. To the south, the dominant trees were oak and chestnut. (Most of the chestnut trees have disappeared, wiped out by an introduced fungus, the chestnut blight.) To the west, the dominant trees are oak and hickory. This type of forest is what Attenborough calls the broad- leaved forest.

Most of the deciduous forests of the world have been cut down by humans. In the
United States at this time, the deciduous forest is increasing in area, as forest returns to the pastures cleared by European colonists and abandoned when their descendants moved west. In Europe and Asia, the deciduous forests are almost completely gone, and have been replaced by pastures, farmland, towns and cities.

Front 59

Describe mycorrhizial associations.

Back 59

SYMBIOTIC RELATIONSHIP BETWEEN PLANTS AND MYCORRHIZAL FUNGI
Most plants have a symbiotic association between their roots and fungi. These
associations are called mycorrhizae

Front 60

What are other types of tropical forests.

Back 60

seasonal forests (with distinct wet and dry seasons), mountain forests (found at higher elevations), cloud forests (wrapped in fog and mists at even higher elevations), gallery forests (which line riverbeds of tropical grasslands and dry forests (with dry seasons of eight months).

Front 61

Describe the stratification seen in a typical tropical rain forest and the times of plants found in each layer.

Back 61

In tropical rain forests, the upper layers are particularly thick. Most of the visible plant and animal life are located in these upper levels.
-emergent layer of trees that are very tall. These trees are often 50-80 meters high and are widely spaced from one another. the crown of leaves receives direct sunlight and the leaves are exposed to wind.
-the canopy, made up of crowns of trees less than 50 meters in height. Contains numorous very tightly packed together. Animals are in great abundance. there is much less light her and is very warm and humid.
-understory of young trees, shrubs, ferns, taller herbaceous (non-woody) plants. The young trees or saplings cannot grow without abundant light.
-forest floor (ground layer) of seedlings, small herbs and small ferns. This layer has very little light. Floor collects dead leaves, branches, logs and other debris.

Front 62

Explain why the soil in tropical rain forests is low in nutrients.

Back 62

Soil is poor b/c many of the nutrients are washed out by the daily rains. Fortunately, the organisms in the leaf litter quickly break down debris. A leaf is totally decomposed in 6 weeks. As a result, nutrients are available only in the top layer of soil (about the first foot or so). Also, nutrients have to be rapidly absorbed by the plants or they might be washed out.

Front 63

What is denitrification? What organisms are responsible?

Back 63

Denitrification refers to the conversion of nitrates back into atmospheric nitrogen. Bacteria are responsible for this step. (Specifically, these bacteria are called denitrifying bacteria.)

Front 64

What is nitrification? What organisms are responsible?

Back 64

Nitrification is a two-step conversion of (1) ammonia into nitrites, and (2) nitrites into nitrates. Both steps require bacteria; these bacteria are called nitrifying bacteria.

Front 65

Describe each step in the nitrogen cycle.

Back 65

Step 1: Nitrogen Fixation. Atmospheric nitrogen is converted (fixed) into ammonia by cyanobacteria (blue green algae) in water, free living bacteria in the soil and sybiotic bacteria in the root nodules of plants in the bean and pea family.
Step 2: Nitrification. This is a two step process. First ammonia is converted into Nitrite by a specific group of bacteria. Then, Nitrite is converted into nitrate by a different group of bacteria
Step 3: Assimilation. Most terrestrial plants use nitrates because it is available. The roots of the plant take up nitrate from the soil. Plant cells then convert nitrate back to ammonia and use it to make proteins and nucleic acids
Step 4: Ammonification: The nitrogen in proteins and nucleic acids is converted by to ammonia by the decomposers (bacteria and fungi). Now, ammonia goes back to step 2 and starts the process all over again.

Front 66

Explain the ecological significance of these organisms: cyanobactera, Azotobacter, Rhizobium.

Back 66

These bacteria are grouped together as nitrogen-fixing bacteria.

Front 67

Describe the two meanings of biodiversity.

Back 67

refers to the number of different types of organisms and the relative abundance of each.

Front 68

Explain how dominance and diversity are related.

Back 68

a community is considered to be more diverse when there is no dominant species. it is less diverse if one or two species are clearly dominant.

Front 69

What is nitrogen fixation? What organisms are responsible?

Back 69

Nitrogen fixation is the conversion of atmospheric nitrogen into ammonia. Biologically, the conversion is done by cyanobacteria in water, bacteria such as Azotobacter in the soil and symbiotic bacteria such as Rhizobium in the roots of legumes. These bacteria are grouped together as nitrogen-fixing bacteria.

Front 70

What is assimilation? What organisms are responsible?

Back 70

Assimilation is the conversion of nitrates into proteins and nucleic acids. Plants are responsible for this conversion.

Front 71

What is ammonification? What organisms are responsible?

Back 71

Ammonification is the release of ammonia due to the breakdown of proteins and nucleic acids. Bacteria and fungi are responsible for this step; these organisms are known as the decomposers.

Front 72

What is the difference between the nitrogen cycle and nitrogen fixation?

Back 72

The nitrogen cycle is the entire process and includes every step in which nitrogen is converted from one form into another. (Look at the diagram to see the entire process or cycle.)

Nitrogen fixation, on the other hand, is a single step in the cycle. Nitrogen fixation is LIMITED ONLY to the conversion of atmospheric nitrogen into ammonia.

Front 73

Explain what is meant by the term "keystone species".

Back 73

a Keystone species is an organism that plays a central role in the functioning of the ecosystem. If the keystone species dies out, this causes a domino effect. Every animal that depends on the keystone species dies out. Their predators then die out and the effect spreads through the food web. The net result: the ecosystem collapses.

Front 74

Unit 3
Describe the zonation or stratification that exists in grasslands. Describe the plant components, processes and animals found in each layer.

Back 74

The herbaceous layer is actually only the top of the 3 layers and not the most important. The ground layer and the underground root layer are the two main layers.

Front 75

Describe the social castes of termites.

Back 75

1) the reproductive individuals. These are the king and queen. Unlike ant societies,
the king lives with the queen and they both live for a relatively long time. Their job duties are simple: start the new colony (the mound), then reproduce. The reproductive individuals keep reproducing during their entire life. A reproductive queen that is laying eggs is very large; the king is not as huge but he is larger than the other caste members.

Termites are fascinating to read about. The king and queen raise the first group
of offspring. When the first set of offspring mature, the king and queen spend the rest of their lives reproducing. The queen becomes huge and turns into an egg-laying "machine."

2) the workers. These are the "peons", the working members of the society that take
care of the offspring, gather food, build the nest, maintain the nest, dispose of dead bodies and any other mundane day-to-day task. The workers have small bodies. Workers can be male or female.

3) the soldiers. These are the "armed forces". Their sole purpose is to defend the
mound from invaders. They are bigger than workers. They have some method of attack, such as very large sharp jaws or chemical spray guns on their heads which disperse nasty compounds that deters most intruders. Soldiers can be male or female (varies between species).

Front 76

What is necessary for an organism to be successful in an evolutionary sense?

Back 76

The name of the game is reproduction

Front 77

Explain why kin selection causes worker termites to care for their siblings instead of having their own offspring.

Back 77

workers are closely related to the king and queen and each other. At that point you begin to see the workers are raising their sisters and brothers. By helping their parents produce more sisters and brothers, their own genes are represented in their millions of siblings.

It begins to make more sense for a worker to stay in the colony and raise their siblings rather than trying to reproduce. The chances of a single worker being able to survive, find a mate, found a new colony and have offspring are virtually zero.

Front 78

Describe the characteristics of deserts (climate and soil).

Back 78

rainfall is scarce. The rate of evaporation is very high, exceeding the rate of rainfall. Temperatures fluctuate widely within a 24-hour period with cool nights and hot days. The ground soaks up heat during the day and then releases it quickly into the air at night.
A desert is hot for part of year and dry.

Front 79

Explain the difference between hot and cold deserts.

Back 79

there are hot deserts, like the Sahara, which are warm throughout the year. Some are cold deserts, such as the Great Basin Desert, with temperatures falling below freezing during the winter. Cold deserts are cold for part of the year. All deserts experience great swings of temperature over a 24-hour period.

Front 80

Describe adaptations used by desert plants to obtain water.

Back 80

(1) Deep root systems, which penetrate the ground for several meters, often to the water table.
(2) Shallow roots that spread out for many meters around the plant and take up almost every drop of soil moisture.
(3) Instead of relying on roots, absorb fog droplets or dew droplets across the leaves.

Front 81

Describe adaptations used by desert plants to keep water once they get it.

Back 81

(1) Have sunken stomata. Plants must have stomata (openings) in their leaves for gas
exchange. However, this also allows water to evaporate. Many plants have sunken their
stomata into pits. (Remember the conifers. They use the same strategy.)

(2) Close the stomata during the hot daytime and open them at night when it's cool.

(3) Get rid of the thin leaves and move photosynthesis and the stomata to the thick
stem. (This is one method used by cacti.

Front 82

Describe adaptations used by desert plants to survive long periods without water.

Back 82

(1) Many plants store water internally. When the rains come, the plant soaks up tremendous amounts of water, which is then stored somewhere in the plant body.

(2) One technique is drought-avoidance. These are ephemeral plants, which survive drought in the form of seeds. When the rains come, the seed germinates, grows and reproduces within a short time. As the normal desert conditions return, the adult plant dies, leaving only its seeds behind.

(3) Some plants are drought-deciduous, losing most of their leaves during the dry season. New leaves are grown when the rains come. The creosote bush uses this strategy.

(4) Some plants are drought-tolerant and are able to withstand desiccation (drying out). One example is the resurrection plant, which becomes brown when it dries out totally, yet becomes green and active when water is available.

Front 83

Describe adaptations used by desert plants and animals to deal with the heat.

Back 83

Bodies absorb heat and there is a lot of heat in the desert. The plant or animal has to either be able to:
(1) tolerate the heat,
(2) modify some part of its body to minimize excess heating, or
(3) avoid the hot parts of the day.

Front 84

Describe adaptations used by desert animals to obtain food.

Back 84

Plants are able to make their own food through photosynthesis. For animals, the availability of food can be variable - lots of food after the rains and then long periods of little food. Many animals, such as desert rodents, store food. Other animals, such as birds and larger grazing animals, have the mobility to move about the desert, seeking the spots where food is more abundant.

Front 85

Compare the food needs of desert ectotherms and endotherms.

Back 85

Ectotherms have a distinct advantage over endotherms, since endotherms require more daily food to fuel their internal reactions. Hence, there are lots of desert ectotherms.

Front 86

Unit 4
Describe and compare the wings of insects, birds, and bats.

Back 86

In insects, the wings are outgrowths of the rigid covering of the body. Most insects have two pairs of wings (for a total of 4). The wings are made of a thin membrane reinforced by struts called veins. The wings flap in a figure-eight motion, generating lift as the wings move down and forward. During the recovery stroke, the wings move up and back. Coordinating all four wings without their smacking into or otherwise interfering with each other demands a high level of nervous system control.

In both birds and bats, one pair of legs, the forelegs, has evolved into the wings. Insect wings did not evolve from legs. They probably evolved from small flaps used by terrestrial insects to soak up heat to raise their body temperature, or by aquatic insects to absorb oxygen from the water.

In birds, the feathers of the wing form the surface that generates lift. The bones of the wing are strong, with some of the fingers fused together for additional strength. As the wings flap, they move in a figure-eight motion. During the downstroke the wing moves down and forward, generating lift. During the upstroke, or recovery stroke, the wing moves up and back. As explained in the video, the feathers can slide over each other, so the shape of the wing surface can be changed. Insects and bats cannot change their wing shape.

In bats, the wing surface is formed by a membrane of skin that is stretched between the neck and the thumb, from there to the third, fourth and fifth fingertips, then to the feet, and from there to the tail. The fingers are very long, to provide support for the wing membrane. The tip of the wing travels in an oval shape instead of a figure-eight as the bat flaps its wings. The wing membrane is often used to help the bat catch insects, serving as a scoop used to bring the food to the bat's mouth.

Front 87

Describe the chemical composition of the atmosphere.

Back 87

The atmosphere is an envelope of gases that blankets the Earth. The most common gases in the atmosphere are nitrogen (78%), oxygen (21%), argon (1%) and carbon dioxide
(0.04%).

Front 88

Describe the layers of the atmosphere including any special characteristics of each layer.

Back 88

Troposphere extends 5 miles above the surface. Above the troposphere is the stratosphere it extends 5-30 miles above the ground. The stratosphere is poor in gases compared to the troposphere, but it does contain an important gas that is normally missing in the layer below ozone.

Front 89

Explain how damage to the ozone layer occurred and describe the consequences for living things.

Back 89

Human activities have damaged this protective layer of stratospheric ozone. Chlorofluorocarbons (CFCs) are chemical compounds used in air conditioner coolants such as Freon. They have many other uses as well. When CFCs leak into the atmosphere, they are carried up to the stratosphere where they break down the ozone molecules. Weakening the stratospheric ozone layer may lead to an increase in skin cancer rates in people and, more seriously, a disruption of food chains as the increased amount of UV light seriously affects plants, algae, and animals.

Front 90

Describe the normal greenhouse effect.

Back 90

The more carbon dioxide there is in the troposphere, the more heat is trapped and the higher the surface temperature will be. This process is called the greenhouse effect.

Front 91

Describe the sources of additional atmospheric carbon dioxide produced by humans and explain how this has affected the rate of global warming.

Back 91

Fossil fuels, such as oil and coal, were formed from an incredible number of photosynthesizers that picked up carbon dioxide and stored it in their tissues millions of years ago. Burning fossil fuels releases a large amount of carbon dioxide to the atmosphere each year. Clearing the land of forests and other plant communities for cropland and dwellings decreases the removal of carbon dioxide by plants, so more carbon dioxide stays in the atmosphere. The combined effects of fossil fuel burning and land clearing is global warming, the warming of the surface of the planet.

Front 92

Describe the consequences of global warming.

Back 92

Global warming may have serious consequences. It will change the patterns of climate and weather around the world. Areas that used to receive enough rainfall to produce crops may
become dry, leading to disruption in the food supply. Other areas may receive more rainfall
than normal, leading to flooding. The plants and animals of all the communities may be unable
to adapt quickly to the changes in climate and temperature. Thus, many organisms may go
extinct. The ice of the polar regions may melt, raising sea level worldwide. Scientists who study
global warming may disagree about the details but they all agree that we should be deeply concerned about possible impacts on the planet.