objective iii: set 1. b.4c – compare the structures and functions of viruses to cells and describe...

Objective III: Set 1

B.4C – Compare the structures and functions of viruses to cells and describe the role of viruses in causing diseases and conditions such as acquired immune deficiency syndrome, common colds, smallpox, influenza, and warts.

Viral Characteristics

Viruses are NOT considered to be living things. Because they use a host cell for energy and replication, they are considered parasites.

Viral Structure Viruses have a simple structure:

1. genetic material (DNA or RNA) 1. RNA viruses (retroviruses) mutate more quickly

(like the influenza virus)

2. a protein coat called a capsid that surrounds the genetic material

3. sometimes they have an envelope

How do Viruses infect cells?

Viruses cannot reproduce on their own.Viruses cannot reproduce on their own.They must replicate by hijacking other They must replicate by hijacking other

cells and using the cell’s machinery to cells and using the cell’s machinery to make more viruses.make more viruses.

A virus can infect only a specific type of A virus can infect only a specific type of cell that it recognizes. cell that it recognizes.

How do viruses infect cells?

Once a virus enters a host cell, two Once a virus enters a host cell, two different processes can occur:different processes can occur:

Lytic cycleLytic cycle

Lysogenic cycleLysogenic cycle

Once inside the host cell, one of two Once inside the host cell, one of two processes can occur. processes can occur.

A.A. Lytic Cycle: Viral DNA enters a cell, Lytic Cycle: Viral DNA enters a cell, reprograms the cell to makes copies of the reprograms the cell to makes copies of the virus, and causes the cell to burst.virus, and causes the cell to burst.

B.B. Lysogenic cycle: A virus integrates Lysogenic cycle: A virus integrates its DNA into the DNA of the host cell, and its DNA into the DNA of the host cell, and the viral genetic information replicates the viral genetic information replicates along with the host cell DNA. Lysogenic along with the host cell DNA. Lysogenic infections may become lytic if the viral infections may become lytic if the viral DNA leaves the host DNA.DNA leaves the host DNA.

The Human Immunodeficiency Virus (HIV) that causes The Human Immunodeficiency Virus (HIV) that causes AIDS is very dangerous because it affects the immune AIDS is very dangerous because it affects the immune system.system.

HIV infects Helper T cells. Normally Helper T cells have HIV infects Helper T cells. Normally Helper T cells have two functions:two functions: activate B cells that produce antibodiesactivate B cells that produce antibodies activate Killer T cells that destroy infected cellsactivate Killer T cells that destroy infected cells

Without Helper T cells functioning properly, you cannot Without Helper T cells functioning properly, you cannot effectively fight off pathogens that can make you sick.effectively fight off pathogens that can make you sick.

People with AIDS die of secondary infections, like People with AIDS die of secondary infections, like pneumonia, because their immune system could not pneumonia, because their immune system could not fight the infection.fight the infection.


The diagram above represents a virus with its surface markers. The diagrams below show various animal cells with receptor sites. Which of the following cells is most likely affected by this virus?

What is the most common threat to a host organism posed by an invading virus?

A Production of viral fluids in the bloodstream

B Fermentation of acids in the digestive system

C Destruction of cells by viral reproduction

D Stimulation of muscle tone in the heart


Which of the following is found in both cells and viruses?

A Silica

B Genetic material

C Digestive cavity

D Flagella


People infected with the human immunodeficiency virus (HIV) have an increased risk of dying from secondary infections. Which of these best explains how HIV increases the danger of secondary infections?

A HIV produces antigens that damage red blood cells.

B HIV adds genetic material from harmful microbes.

C HIV destroys helper T cells.

D HIV consumes beneficial microbes in the body.


Viruses can be transmitted in a variety of ways. The virus that causes SARS (severe acute respiratory syndrome) can be transmitted when an infected person coughs or sneezes. This virus is transmitted in a manner most similar to the transmission of—

F smallpoxG AIDSH West Nile virusJ influenza


B.4D – Identify and describe the role of bacteria in maintaining health such as in digestion and in causing diseases such as streptococcus infections and diphtheria.

Parts of a bacteriumBacteria are prokaryotic cells.

They do not have a nucleus, the DNA is free in the cytoplasm.

Plasma (cell) membrane and cell wall:

1. Allow materials in and out of the cell

2. Protection and support

Flagella: whip-like tail for movement

Ribosomes- translate genetic material into proteins

Reproduction

1. Most bacteria reproduce very quickly by an asexual process of cell division called binary fission.

2. Daughter cells are identical to the parent cell.

Binary fission

Importance of Bacteria

Bacteria are vital to maintaining the living world.

1. Producers: Capture energy by photosynthesis, basis of some food webs.

2. Decomposers: Break down dead organic matter, returning it to the soil for other organisms. Decomposers are important in nutrient cycles (like the carbon cycle).

Importance of Bacteria

3. Human Uses: We have bacteria living on all surfaces of our bodies and ones such as E. coli are essential for our digestion.

1. We provide them with a warm environment, and they provide us with essential vitamins that we cannot produce on our own. This is a mutualistic symbiotic relationship.

2. We use them in food production because some bacterial fermentation is used to make yogurt, sour cream, vinegar, buttermilk, and more)

Harmful Bacteria

Any disease causing agent is called a pathogen- it could be bacterial or viral.

Bacteria cause disease in one of two ways:

1. Breaking down our body’s cells as food

2. Releasing toxins that travel through the body and damage our cells

Preventing Disease

1. Good hygiene- wash hands thoroughly with soap and water.

2. Vaccines- a weakened or dead form of the pathogen (bacteria or virus) is given to a patient whose body will form an immune response to it. Once that immune response happens, your body remembers it forever and if the real pathogen gets in your body, your immune system will react quickly and kill it immediately.

Treating Bacterial Disease

3. Antibiotics- prevent growth and division of bacteria so that our immune systems can fight the illness more easily.

• Antibiotics are for bacterial infections and are NOT effective against viral or fungal infections.

• Antibiotics kill the beneficial bacterial that help up digest food, which can disturb our digestion temporarily.

First Line of Defense:The outer layer of the body

Goal:prevent organisms from gaining access to the body

Details: Physical barriers: skin Chemical barriers: sweat,

tears, saliva, mucous, skin

These contain enzymes that break down cell walls of many bacteria

Second line of defense: Cells and proteins in our blood stream

Goal: recognize, neutralize and destroy invaders inside the body Details: inflammation and fever (swelling, redness, warmth, pain)

Increased blood flow brings cells to fight infection

Third Line of Defense: The Immune Response

Two types of white blood cells are involved:

T cells: provide defense against abnormal cells and pathogens inside living cells

Helper T cells activate B cells and Killer T cellsKiller T cells destroy infected cells

B cells: provide immunity against antigens and pathogens in the body fluids by making antibodies

Which organism lives in the human intestine and aids in the digestive process?

A The bacterium Escherichia coli

B The fungus Trichophyton rubrum

C The protozoan Entamoeba coli

D The algae Fucus vesiculosus


Some antibiotics cause patients to exhibit digestive side effects. These side effects are most often the result of —

F bacteria being killed in the digestive tract

G the antibiotics being converted into stomach acids

H too much water being drawn into the digestive tract

J the stomach wall being torn


Many species of bacteria can be found in the human mouth. Which of these explains the great variety of bacteria in the mouth?

F Large volumes of air cause bacteria to change form.

G Salivary glands cause mutations in bacterial populations.

H The presence of nutrients makes the mouth a favorable habitat.

J Calcium in the teeth provides a suitable pH environment.



All of the following symptoms are likely associated with bacterial infection except —

F skin rashes or lesions

G elevated body temperature

H swollen glands or tissues

J increased red blood cell count

B.7A – Identify evidence of change in species using fossils, DNA sequences, anatomical similarities, physiological similarities, and embryology.

includes

which is composed of which indicates which implies which implies

Evidence of Evolution

Physical remains of organisms

Common ancestral species

Similar genes Similar genes

The fossil recordGeographic

distribution of living species

Homologous body structures

Similaritiesin early

development

Fossils:

Relative Dating – layering of fossils: older fossils are found below more recent ones. Living organisms resemble fossils although differences may be evident.

Geographic distribution of Living Organisms

Common ancestor from mainland South America migrated to Galapagos Islands.

Each island habitat in the Galapagos has different selective pressures acting on the organisms.

Natural selection acts on the populations separately, which over time, causes the populations to diverge morphologically and physiologically.

Geographic distribution of Living Organisms

Organisms that are unrelated in the same types of habitats elsewhere in the world had the same selective pressures acting on them, and therefore, developed the similar characteristics.

Embryology and Homologous Body structures

Embryology – early stages of vertebrate development are all very similar. They start to diverge into frog, fish, alligator, human, and ostrich form in later stages of development.

Embryology and Homologous Body structures

Homologous body structures – developmentally, a human arm, whale fin, alligator leg, and bird wing share the same bones, but due different selective pressures and occupying different niches, these bones can have dramatically different structures.

Genetic data-

We used to compare species based solely on their morphology (present day and fossils)

Now, comparative studies of DNA sequences of organisms shows how similar DNA is between some species, and different from other species

This can confirm what was previously thought, or it can cause scientists to rethink relations between organisms.


The table shows a comparison of some amino acids found in cytochrome c. The two organisms in the table that are most closely related are —

A Q and TB R and SC Q and RD Q and S


Birds and reptiles are similar in that they are vertebrates and lay eggs. They differ in that reptiles have teeth and birds have beaks. Some birds do possess teeth. However, these teeth are present only in the embryonic stage. Which conclusion is best supported by the presence of teeth in bird embryos?

A Birds and reptiles share a common ancestor.B Modern reptiles are the ancestors of modern birds.C Birds and reptiles eat similar types of food.D Ancestors of reptiles had beaks similar to those of birds.

B.7B – Illustrate the results of natural selection in speciation, diversity, phylogeny, adaptation, behavior, and extinction

Definitions and Concepts:

Adaptation – any inherited characteristic that increases an organism’s chance of survival and ability to reproduce. Ex. Monarch butterfly is poisonous to eat

they have special coloration to warn predatorsalso viceroy butterflies copy their coloration to protect themselves

Biological Fitness – the ability of an organism to survive and reproduce.


Struggle for Existence – when members of a species compete regularly for space, food, and other necessities of life

Natural Selection or Survival of the Fittest– the process by which individuals that are better suited to their environment survive and reproduce most successfully.


Evolution – the theory that groups of organisms, as species, may change with the passage of time so that their descendants differ morphologically (how the look) and physiologically (how they function) from their ancestors.

How does natural selection drive evolution?

Individual organisms of a population differ and much of this variation is heritable.

Organisms produce more offspring than can possibly survive and those that do not survive do not reproduce.

Those individuals that are better able to survive and reproduce pass on their more successful adaptations to their offspring.

Speciation: Formation of a new species

A population must be separated into two distinct populations for natural selection to act on them separately, such that they are reproductively isolated (lose the ability to produce fertile offspring).Geographical isolation: physically separatedBehavioral isolation: different mating ritualsTemporal isolation: mate at different times


Which of the following is most likely to cause increases in a predator population?

F Fewer prey

G A reduction in competition

H More parasites

J A period of drought

A man treated his home with a pesticide that kills roaches. The first application of the pesticide killed 92% of the roaches. Two months later he applied the pesticide to his home again, but the second application killed only 65% of the roaches. What would best explain the decrease in the effectiveness of the pesticide?

F The pesticide is effective only against mature roaches.

G Once roaches learned how to fight the pesticide, they taught others.

H The surviving roaches were naturally resistant to the pesticide, and that resistance was inherited by their offspring.

J The pesticide caused some of the roaches’ digestive systems to mutate and metabolize the pesticide.


The maps below show the geographic ranges of four species of the order Lagomorpha, which includes rabbits and hares. In which range would developing white fur in winter most likely not be anadvantage for a member of this order?


The guppy is a species of small freshwater fish. Scientists observed that the average size of guppies in a pond decreased over a few years after a guppy predator was introduced into the pond. Which of the following best explains the change in guppy size?

F Speciation

G Convergent evolution

H Inbreeding

J Natural selection


B.12B – Interpret interactions among organisms exhibiting predation, parasitism, commensalism and mutualism.

Symbiosis: Relationships between organisms that live together closelyMutualism (+/+):

Both benefitCommensalism (+/0):

One benefits, one is not helped or harmedParasitism (+/-):

One benefits, one is harmed

Community Interactions

Community Interactions

Competition (-/-): Both organisms are harmedResourceCompetitive exclusion principle

Predation (+/-):One organism benefits, one is killedPredator and prey

B.12B – Interpret interactions among organisms exhibiting predation, parasitism, commensalisms and mutualism.

This relationship is an example of —

A predationB parasitismC mutualismD commensalism

An oakworm caterpillar feeds on the leaves of an oak tree. This type of interaction is —

F mutualisticG commensalisticH competitiveJ parasitic


After being introduced in the 1930s, the fire ant (Solenopsis invicta) became established throughout much of the southern United States. One biological way to control fire ants might be to introduce organisms that are —

A mutualistic with fire ant queens

B nurtured by fire ant workers

C preyed on by fire ant drones

D parasitic to fire ant larvae


A hummingbird feeds on the nectar of a flowering plant. In this process the bird gains nutrition while spreading the plant’s pollen to other flowers. The relationship between hummingbirds and flowering plants can be described as —

F commensal

G predatory

H parasitic

J mutualistic


Which word best describes the fungus in the situation above?

A Predator B ProducerC ParasiteD Decomposer


B.9D – Analyze the flow of matter and energy through different trophic levels and between organisms and the physical environment.

B.12E – Investigate and explain the interactions in an ecosystem including food chains, food webs and food pyramids.

Feeding Relationships Autotrophs- organisms that can make their own

food Producers: use sun or chemicals to make food

Heterotrophs: must obtain their food from other sourcesConsmers: organisms that eat Decomposers: absorb food from external

environment to obtain energy

Types of HeterotrophsConsumers:

Herbivores- eat vegetationCarnivores- eat other consumersOmnivores- eat vegetation and other

consumersDecomposers- decompose dead

material and return organic material to earth

Heterotroph & CarnivoreHeterotroph & Carnivore

What is each organism?

Heterotroph & Decomposer Autotroph/

Producer

Heterotroph & Omnivore

Feeding Relationships

Energy flows in one direction through an ecosystem: from the sun, through autotrophs through heterotrophs and all eventually lost as heat

Food Chain: single display of energy transfer in an ecosystem. Arrows point toward the organism receiving the energy, or rather the arrows show the direction of energy flow

Food Web: interwoven food chains within an ecosystem

Trophic Levels: each step in a food chain or food web or pyramid-producers-primary consumer-secondary consumer-etc.

Ecological Pyramids

The direction of energy flow through the trophic levels can be shown through food chains and food webs.

To show relative amounts of energy per trophic level, we can use a pyramid

Ecological Pyramids

Energy Pyramid: the producers are at the bottom with the total amount of sun energy captured.

Each trophic level that the energy flows into only receives 10% of the energy from the previous level.

The other 90% is lost as heat


Energy used by producers in a grassland food web is provided by —

F sunlight

G photosynthesis

H oxygen

J carbon dioxide


In this food web, the bacteria probably function as —

A producersB herbivoresC decomposersD carnivores


A food pyramid represents the relative amount of energy in trophic levels. Which of the following correctly shows a food pyramid?


Which organisms in this food web can be described as both primary and secondary consumers?

F HawksG WeaselsH RaccoonsJ Mice

Wolves and hawks are at the same trophic level because they —

A both live on landB are both large mammalsC both eat primary consumersD have similar hunting patterns


Approximately how much of the energy available in the tissues of the producer is eventually incorporated into the tissues of a secondary consumer?

A Less than 1%

B Between 20% and 30%

C Approximately 50%

D More than 50%


In this food chain, the spiders are —

A producers

B primary consumers

C competitors

D secondary consumers


A person living near this pond wants to reduce the mosquito population. The mosquito population included in this food web could be reduced by —

A planting more duckweedB catching more minnowsC removing some martin housesD adding more shelter for frogs


According to this food web, which of these is an omnivore?

F Caterpillar

G Mouse

H Ant

J Fly larva


The difference in the size of each layer of this food pyramid is primarily the result of the difference in —

F food choices of individual nichesG oceanic zones of habitatH the amount of food energy at each trophic levelJ the relative heights of the organisms


The picture shows a piece of rotting wood. Which of these does the picture demonstrate?

F Photosynthesis occurringG Wood regeneratingH Decomposers growingJ Genes transforming


B.13A – Evaluate the significance of structural and physiological adaptations of plants to their environments.

Specialized tissue in plants

Roots- anchor the plant, take in water and nutrients

Stems- support the plant, transport water and nutrients

Leaves- site of photosynthesis.

Specialized parts of the leaf:

Stomata (singular: stoma) are openings that allow water and gases (oxygen and carbon dioxide) in and out, and they are controlled by guard cells.

Cuticle is a waxy coating that helps prevent water loss via transpiration (evaporation).

Xylem and phloem transport water and nutrients

Cuticle

Guard cells

Stoma(pl. stomata)

XylemPhloem

Plant Adaptations

Plant Adaptations (inherited characteristics that increase an organism’s chance of survival)

Plant Adaptations

1. Seed dispersal:

a. decreases competition and over-crowding

b. can introduce the seed into a new habitat

Seed Dispersal

Name: Air

Description: Seeds are carried by wind

Example: Dandelion, Tumbleweed, Ash and Maple trees

Seed Dispersal

Name: Water

Description: Seeds or fruits are dropped from the plant into the rivers, lakes or seas; seeds float

Example: Coconut

Seed Dispersal

Name: Animal

Description Example

Attach to animal fur

Ingestion followed by excretion at a different location

Birds eat fruit and throw away the seeds

Burrs

Apple

Berries

Seed Dispersal

Name: Self

Description: Forcible ejection by various mechanisms

Example: Dwarf mistletoe, Pea plant, Squirting cucumber

Plant Adaptations

2. Chemical defenses:

a. Some plants produce chemical compounds that are toxic to insects that may feed on them

Plant Adaptations3. Aquatic plants. These plants live in mud with

little oxygen. Adaptations include:

a. Tissues with large air-filled space:

oxygen can diffuse from the above ground part of the plant to the roots.

b. Seeds that float in water.

Plant Adaptations4. Desert plants. These plants must be able to

survive strong wings, daytime heat, sandy soil, and infrequent rain. Adaptations include:

a. extensive roots: increase surface area to increase water absorption

b. reduced leaves (spines): to decrease water loss

c. dormant seeds: only germinate when there is enough water

d. thick stems: store water

Plant Adaptations

5. Carnivorous plants: Live in wet, acidic environments with little nitrogen. Adaptations include:

a. Ability to trap and digest insects as a nitrogen source


The first equation represents photosynthesis. Plants use energy from sunlight to produce sugar and oxygen from carbon dioxide and water. The second equation represents aerobic respiration. Plants and animals release stored energy in a reaction between sugar molecules and oxygen. This reaction produces carbon dioxide and water.

Which structure regulates gas exchange during the processes of photosynthesis and

respiration?A QB RC SD T

This seed is best dispersed by —

A waterB birdsC windD insects


Which of these characteristics might help a plant species survive in an area with limited sunlight?

F Bright flowers

G Large leaves

H Short stems

J Thick cuticles


Which of the following characteristics could help short plants survive in areas with limited sunlight?

F Broad leaf surfaces

G Brightly colored flowers

H Thick stems

J Shallow roots


Some mesquite trees have deeper roots than any other plant in the desert. How are deep roots an adaptation for survival in the desert?

F Deep roots can protect the tree from predators.G Roots encounter cooler conditions far below the desert surface.H Roots can extend great distances to reach water.J Deep roots interact with beneficial bacteria below the surface.


Which of the following is an adaptation most likely observed in plants growing along Aransas Bay?

A Sensitivity to green light

B Tolerance of saltwater

C Extension of root length

D Resistance to predation


Cacti grow slowly compared to most other plants. The fact that cacti keep their stomata closed for much of the day can help explain this growth characteristic. Which of these best explains the advantage of keeping stomata closed during the day?

F It limits water loss through transpiration.G It conserves oxygen produced in photosynthesis.H It recycles carbon dioxide within plant systems.J It protects plant tissues from predators.


Objective III: Set 2


Most viruses infect a specific kind of cell. Which of the following are infected by the human immunodeficiency virus (HIV)?

F Helper T cells

G Liver cells

H GABA-receptor cells

J Red blood cells


Viruses differ from bacteria in that all viruses —

F cause insect-borne diseases

G can be destroyed by antibiotics

H have rigid cell walls

J must be reproduced in living cells


One characteristic shared by a virus and a living cell is that both —

F store genetic information in nucleic acids

G have a crystalline structure

H gain energy directly from the sun

J use glucose for respiration


Which of these events is most likely to cause a widespread influenza outbreak?

F People in northern regions are affected by weather patterns.

G The influenza virus is recognized by host immune systems.

H Global warming causes increased winter precipitation.

J People lack immunity to a new strain of flu virus.


Why is Sendai virus used as a vaccine against HPIV-1?

A It alters the protein coat of HPIV-1.B It makes cells chemically unrecognizable to HPIV-1.C It forms a protective barrier against HPIV-1.D It triggers the production of antibodies that fight HPIV-1.


Which of these does a virus need in order to multiply?

A Chloroplasts from a host cell

B A host cell to provide oxygen for the virus

C New ADP from a host cell

D A host cell to replicate the virus’s DNA


Which of the following cannot metabolize nutrients?


Some bacteria benefit mammals by helping with —

F growth

G defense

H digestion

J respiration


Which of the following factors helps spread disease-causing bacteria?

F Low temperaturesG Access to new hostsH Mutation by heat energyJ Availability of light


Cows and other ruminants are herbivorous animals. Their diet includes cellulose, which must be fermented before it can be digested. Which of these aid in the fermentation of cellulose in a cow’s digestive system?

F Bacteria

G Fungi

H Algae

J Viruses


A study shows that 40% to 100% of raw poultry is contaminated by disease-causing bacteria. Which of the following activities provides people the best protection from these bacteria?

F Rinsing dishes thoroughly

G Eating a balanced diet daily

H Visiting a doctor regularly

J Cooking foods properly


Streptococcus infection in a person’s throat can cause pain and fever. Streptococcus can be controlled by antibiotics. Streptococcus is a—

F virus

G bacterium

H protozoan

J fungus


The table shows an amino acid comparison of cytochrome c, a protein involved in cellular respiration in aerobic organisms. The two organisms in the table that are least genetically related are the —

A silkworm moth and the fruit flyB silkworm moth and the screwworm flyC fruit fly and the screwworm flyD fruit fly and the hornworm moth


The diagram illustrates how some characteristics of the horse have changed over time. Along with the difference in size, what is another anatomical difference between the modern horse and its ancestors?

F The structure of the tooth has been adapted for eating meat.

G The size of the molars has decreased.

H The length of the forefoot has decreased.

J The number of toes has decreased.


Because of this animal’s adaptations, it would be most successful at —

F competing with birdsG making its own foodH hiding from predatorsJ running very rapidly


Which of these conclusions can be made based on the graphs shown above?

A Larger mosquitoes have migrated into the area.

B Smaller mosquitoes are being eaten by larger mosquitoes.

C A mosquito length of 2 cm has become a disadvantage in this environment.

D Mosquitoes with a body length of 3 cm have the longest life span.


Some bacteria thrive in hostile environments, such as salt flats, boiling-hot springs, and carbonate-rock interiors, primarily because of bacteria’s —

F biochemical diversityG small sizesH round shapesJ methods of movement


Which of the following explains this phenomenon?F CompetitionG ExtinctionH PredationJ Speciation


The model shows a demonstration a student prepared using black and white marbles to show how populations of organisms can change. Which of the following concepts is best illustrated by this demonstration?

F Evolution of a predatory speciesG Genetic drift accompanying natural selectionH Environmentally induced genetic mutationsJ Immunity from virulent microorganisms


The myxoma virus was used to control an overpopulation of European rabbits in Australia. When first introduced in the mid-1900s, the virus greatly reduced the European rabbit population. Today the virus is not an effective control of the European rabbit population. Fewer European rabbits are affected by the virus today because they have—

F learned to avoid the virus

G moved away from infected areas

H undergone a change in diet

J developed resistance to the virus


Which of the following is best supported by the information shown above?

F These lizards evolved in arid habitats.G Modern lizards drink more water than their ancestors did.H These lizards cool themselves by evaporation.J Modern lizards excrete more water than their ancestors did.


Clown fish are small reef fish that seek protection from predators by sheltering themselves among the stinging tentacles of sea anemones. Clown fish are very territorial and can potentially scare off predators of sea anemones. This relationship is an example of —

A neutralism

B mutualism

C parasitism

D commensalism


Which situation best represents a mutualistic relationship?

A A tapeworm absorbing nutrients from the intestine of a dog

B An orchid being pollinated by a nectar collecting wasp

C A human losing blood to a feeding mosquito

D An armadillo rooting in the soil at the base of an oak tree


Beechdrops (Epifagus virginiana) are leafless plants that lack chlorophyll. Beechdrops get their nourishment from the roots of beech trees, which reduces the amount of nutrients available to the trees themselves. This interaction is best described as —

A predatory

B parasitic

C commensalistic

D mutualistic


Which of these best describes the relationship between epiphytes and trees?

F ParasitismG MigrationH CommensalismJ Predation


Which of these is the best example of a mutualistic relationship in an aquatic environment?

F Some fish can survive repeated infections by harmful bacteria.

G Some fish have bacteria living in their digestive tract that help the fish digest food.

H Some bacteria are present in aquatic food chains in which fish are secondary consumers.

J Some bacteria are aquatic decomposers that recycle nutrients useful to fish.


Insecticides help humans compete with insects for a resource. Which resource is most likely to be preserved for humans through the use of insecticides?

F Sunlight

G Water

H Food

J Air


About 10% of the energy at one trophic level is passed to the next level. What usually happens to the energy that is not passed to the next trophic level or used to carry out life processes?

A It is given off as heat.

B It is stored as vitamins.

C It is used in reproduction.

D It is used in protein synthesis.


Which diagram best shows how the amount of stored energy changes going up a food chain?


The diagram shows several phases of the nitrogen cycle. Which of the following describes the most likely effect of removing some plants from the area by using chemical herbicides?

A The rate of erosion of rocks on the ground would be slowed.B The flow of necessary nutrients would be disrupted.C The ability of plants to complete photosynthesis would be increased.D The infiltration of water into the ground would be halted.


The diagram above is intended to show relationships in an ecosystem. What do the arrows represent?

F The direction of population migrationG Differences in dietary habitsH Progressively smaller organismsJ The direction of energy flow


Which of these groups of organisms would most likely have accumulated the largest concentration of a long-lasting chemical pollutant in their bodies?

A PhytoplanktonB ZooplanktonC Lake troutD Gulls


In this food pyramid, which level contains the greatest amount of energy?

A Tertiary consumers

B Secondary consumers

C Primary consumers

D Producers


The table lists four groups of factors found in a particular ecosystem. Which group consists of only abiotic factors?

F Group 1G Group 2H Group 3J Group 4


In this diagram of a marine food web, which term describes the sea turtles?

A Aquatic herbivores

B Autotrophic producers

C Third-level consumers

D Primary decomposers


Which of these is a food web based on the relationships described above?


Compared to annual rings of trees that have experienced years of sufficient rainfall, the annual rings of trees that have experienced a dry period will —

F be softer

G grow at a faster rate

H be thinner

J photosynthesize at a faster rate


Species of the genus Toxicodendron, which includes poison ivy and poison oak, produce a gummy oil that causes a severe itchy rash in some animals. This substance is part of the Toxicodendron species’—

F defense mechanismsG nutritional processesH support systemJ clinging ability


Which of the following leaf types is most likely to help a plant survive in an arid habitat?


Which of these structures protects a leaf from drying out?

F QG RH SJ T


Plant leaves have a waxy covering called a cuticle. When some plants are stressed by lack of water, their cuticle increases in thickness. What does this action demonstrate?

A Alternation of generations in plantsB Structural response to the environmentC Differentiation of vascular tissue in plantsD Genetic mutation induced by the environment


Some species of kelp anchor themselves to the seafloor. These species have small air sacs, called air bladders, at the base of each leaf. The air bladders raise the top of the kelp to the water’s surface. What advantage do air bladders give the kelp?

A They allow the kelp to obtain more salt from the water.

B They prevent the kelp from breaking during a storm.

C They allow kelp leaves to receive greater amounts of sunlight.

D They provide the kelp with protection from herbivores.

objective iii: set 1. b.4c – compare the structures and functions of viruses to cells and describe...

Documents

b cells

helper t cells

infected cells

cells machinery

killer t cells

functions of viruses

host cell dna

various animal cells