andi citra pratiwi 091404170

8/7/2019 andi citra pratiwi 091404170

1/12

Name : Andi Citra Pratiwi

Reg. No : 091404170

1. Compare and contrast autotrophs and heterotrophs!Answer: Autotrophs are the organisms which are able to manufacture their own foods,

since they are able to make organic compounds from inorganic materials in the

environment by using light energy (as energy source) and chlorophyll through

photosynthesis process. Plant is an autothroph organism. Meanwhile, heterotrophs are

the organisms which are not able to manufacture their own foods, since they can not

make organic compounds from inorganic compounds. Thus, they must obtain their food

(organic compounds) from the environment. Examples of heterotrophs are carnivores,

herbivores, and decomposers.

Noteworthy, autotrophic nutrition lays down the building blocks of life and

provides complex organic molecules for the consumption of heterotrophic organisms.

Without autotrophic nutrition, there would be no life.

2. Discuss the consequences of being autotrophic. How have plants responded to life asautotrophs?

Answer: Plants require specialized structures for adapting the autotrophic mode of

nutrition. Autotroph means that the plant should process the inorganic molecules to be

organic molecules. Since the plants can not do movement, plants should be adapted for

harvesting dilute nutrients in environment. The adaptations give rise to specialization in

plants. The specializations which occur as the consequences of being autotrophic, are as

follows:

a. Plant needs an organelle which can be used to convert the inorganic molecules to beorganic compounds. Thus, the plant posses a chloroplast as the organelle which will

process the inorganic compounds to be organic compounds.

b. To do photosynthesis, the plant requires efficient light harvesting. Thus, they havebroad leaves to maximize surface area for light harvest.

c. The photosynthesis requires an apparatus for gas exchange. The plant need toexchange the photosynthetic gasses (take up carbon dioxide and get rid of oxygen)

with the environment. Thus, the leaves of plants have pores in the surface (stomata)


2/12

which serves to regulate the entry/exit of gasses and prevent the loss of excessive

water.

d. The plants need thin leaves for light absorption and gas exchange. Within the thin leaf,most chloroplasts are found in the upper layer of cells, the palisade layer, which is the

tissue layer just beneath the epidermis. This makes sense since these cells will be

receiving the greatest amount of light of any region in the leaf. Besides that, the

advantage of having large leave is that they provide lots of surface area for absorption

of carbon dioxide.

e. The plant requires a water supply to do photosynthesis. Since the plant can not dolocomotion as animals, they must have an organ to help fulfill their need of water.

Accordingly, plant posses roots which serves to obtain water from soil. A

specialized tissue of the root which serves to transport the water from soil is called

xylem.

f. The plant requires a mechanism to transport end products of photosynthesisthroughout the plant. Thus, the plant posses phloem tissue enable the transportation of

carbohydrate (as the result of photosynthesis) from leaves to roots, fruits, and other

tissues where required.

3. How do plants exploit their environment? Consider dendritic form, asexualreproduction, indeterminate growth, heterophylly, foraging and architectural

design in your response.

Answer:

The inability of plant to escape an unfavorable environment has resulted in the

evolution of developmental strategies that allow for flexibility in responding to local

environmental fluctuations. This ability is reflected from the ability of plants to exploit

their environment. The way of plants to exploit their environment are as follows:

a. Plants are dendriticDendritic means tree-like or filamentous. The advantage of this shape is that it

provides a large surface-to-volume (s/v) ratio which enables a plant to exploit a large

area of the environment.


3/12

b. Plants have indeterminate growthIndeterminate growth is the process by which a plant continous to grow and get larger

throughout its life cycle. The advantage of this is that it allows the plant, especially

roots, to grow into new areas.

c. Plants have an architectural designThe body of plant is constructed like a building. It is built of a limited number of units,

each of which is relatively independent of the others and that are united into a single

structure. The leaves, stems, and roots of plant are analogous to a room in the building.

Each room is somewhat independent, yet they all function together to make an

integrated whole.

Because of their indeterminate growth and architectural design, plants are not

limited by size. This gives plants the ability to colonies and exploit new areas for

resources.

Because of indeterminate growth, plants are not a static shape. Plants constantly

change shape by adding/loosing parts. Thus, growth in plants occurs by the addition of

new units.

d. Plants have a well-developed ability to reproduced asexuallyAsexual reproduction is the way of reproduction which will be done by the plant at the

plant in a though condition. This can be viewed as a quick and energetically

inexpensive way to expand the influence of the parent into a new location. Plants

under nutrient stress should increase their rate of asexual reproduction.

e. Plants (may) exhibit heterophyllyHeterophylly refers to leaves with different shapes. Sun leaves are tend to be smaller

than shade leaves. The smaller leaves functions to reduce transpiration. Meanwhile,

the shade leaves which is bigger, serves to obtain more light for photosynthesis.

f. Plants can forageThe growth pattern of plants, especially vines and plants with stolons (runners), are

similar to the foraging tactics of animals. As an example, rhizomes to avoid

competition.


4/12

4. Compare and contrast animals and plants in terms of body design (i.e. architecturalvs. mechanical design).

Answer: Plants typically responded by various growth movement to unpredictable,

usually short-term environmental fluctuation, like changes in temperature or light. Plant

usually responded to predictable, often longer-term environmental changes, like seasonal

changes, by growth and developmental changes because of the constraints of their

architectural design,

In contrast, animals typically respond to their environment behaviorally (by

movement). Since they are motile, they can move to a favorable position. In fact,

because they are motile, they need a nervous system to respond to the environment.

Plants do not need a nervous system since they are constrained to respond to the

environment by growth/developmental changes. Hence, they (plants) never had pressure

to evolve a nervous system.

5. Discuss some of the mechanisms by which plants sense changes in the environment.Why are these important?

Answer:

Plants respond to the changes in their environment in variety of ways. Those are

important to be done by plants, in order that they can survive. Various response of plants

to changes in environment are as follows:

a. Plants typically respond by various growth movement to unpredictable short-termenvironmental fluctuations, like changes in temperature or light. For example:

- some flowers like crocus are temperature sensitive and open when it is warm andclose when it is cooler. The flowers of an alpine species (Gentiana algida) close

up before a thunderstorm. The flowers actually respond to the decreased

temperature associated with the storm front and close to avoid pollen being

washed out of the flower by the rain.

- Light is one of the most important environmental cues for plant development. Thisphenomenon is called photomorphogenesis. The example is etiolation. Etiolation

is the response of plants to growth in the dark or with reduce light. Etiolated


5/12

plants are typically yellow, have elongated internodes (stems) with unfolded

leaves and the stems are thinner. These features can be considered ways of

conserving energy.

b. Plants usually respond to predictable, often longer-term environmental changes, likeseasonal changes, by growth and developmental changes because of the constraints

of their architectural design. Since this changes take time, a plant must know or

predict when the environment will change and prepare for the change.

Indeterminate growth is important here since it provides plants with the ability to

change developmentally through the life cycle. Some example for this phenomenon

include: preparing for winter (by forming buds in summer) and photoperiodism

(timing flowering so the appropriate pollinator is available and that the seeds have

enough time to develop before winter), nyctinasty (sleep movements), and circadian

rhythms (various types in response to day/night).

6. Identify some of the physical and biological threats to plants. How do plants protectthemselves from these dangers?

Answer:

a. Physical DangerWind, water (flood), drought, cold (winter), are among of the physical dangers that

a plant faces. In general. Plants cope with these (at least the predictable ones like

winter and drought during summer) by dormancy, senescence, and even death. The

evergreen and deciduous lifestyle are in part a response to adverse conditions.

Evergreens are much better able to tolerate cold, dry conditions. They also do better

in poor soil because they dont loose as many leaves. Plants also respond to

environmental challenges morphologically. For instance, Arctic and montane herbs

are small and hug the ground.

b. Biological DangerBiological dangers are living-things which are able to harmful to plants. Predators

(=herbivores) and competitors (=other plants) are biological danger for plants. To

protect themselves, plants have evolved as follows:

- Anatomical weapons


6/12

Anatomical weapons, such as thorns, hairs, and thick cuticle. Some plants are

even smart enough to stop producing defences when they are out of rang of a

herbivore. For example, the upper parts of Acacia trees above giraffe height

produce few thorns. Similarly, holly leaves have few prickles above herbivores

height.

- Chemical weaponsPlants are able to produce toxic or unpalatable chemicals to protect themselves

against biological dangers. These can be inducible (produce in response to

attack) or constitutive (always present).

- MimicryMimicry is the process of tricking predators. The plants will do specialization

in its morphological structure to trick predators. For instance, Alseuosmia is a

non-toxic New Zealand plant that looks very similar to Wintera pseudocolorata

(a toxic species).

- Armed forcesSome plants, like wild tobacco, when attacked by herbivores release volatile

chemicals that summon predatory insects to the damage plants. These insects in

turn, kill the herbivores. Overall, volatile chemicals play a very important role in

plant defense. These chemicals, released when the plant is attacked by an

herbivore serve as signals that can warn other plants that danger is imminent, can

tell herbivores that the chemical defense system of the plant is ready for them

and that should go pick on someone else, and the volatiles themselves help to

repel the attack.

7. How do plants find a "mate" and disperse offspring?Answer: Plants find a mate (do gamete transfer) by relying on various pollination

vectors. For example: Prior to pollination, the orchid released a fragrance that was an

aphrodisiac for the male but once the flower was pollinated it produced a fragrance to

repel him.

Fruits/seed dispersal mechanism help disperse offspring. This dispersal process can be

helped by certain agents. The agents can be biotic agent (birds, mammals, insect) or a-


7/12

biotic agents (wind, water, gravitation). For example: when a few fruit of Hamelia patens,

a neo-tropical tree, are removed. It stimulates the rest of fruit to ripen. It essentially tells

them that a dispersal agent is in the area.

8. Discuss some of the problems unique to the plant way of life. In general how haveplants responded to each of these problems?

Answer:

1. Problem: Plants can not run away from both physical and biological dangers, sincethey can not do motility. Thus, when conditions get though, they must fight it out.

To solve this problem, plants have typical adaptations, as follows:

a. To defend themselves against physical danger such as winter, the plants will dodormancy. Plants also respond to physical danger morphologically, for example:

xeric plants minimize their leaves to minimize water loss; Arctic or montane

herbs are small and hug the ground.

b. To defend themselves against biological dangers, such as herbivores, plants haveevolved anatomical weapons (thorns, hairs, thick cuticle) and also chemical

weapons (produce toxic, unpalated chemical). Besides that, some plants have

also evolved Armed Forces, like wild tobacco, when attacked by herbivores

releases volatile chemicals that summon predatory insects to the damaged plants.

These insects in turn, kill the herbivores. Thus, the plants can be safe.

2. Problem: As non-motile organism, plants can not seek a mate (for gamete transfer) oreasily disperse offspring.

Plants solve this problem by relying on various pollination vectors. Pollination

vectors are the agents which help the process of moving the pollen grain from the

anther of a stamen to the stigma of a carpel. Pollination vectors are water, wind, bee,

and also butterfly. Fruits/seed dispersal mechanism help disperse offspring.

3. Problem: As non-motile organism, plants are unable to move to a more favorablelocation to carry out its vital function. A plant is stuck once the seed germinates.

To solve this problem, there are a few tricks that plants use to ensure that the seed

will germinate in a favorable environment. For instance: Some seeds, like certain

varieties of lettuce, require LIGHT for germination. This is a mechanism to insure


8/12

that they germinate on the soil surface. Besides that, plants also do specialized

dispersal mechanism to insure the seed getting into the proper place.

9. Think about the statement "Plants are smarter than you think!"Answer: Plants are smarter than you think. Before giving some arguments about this

statement, the first thing that should be done is to understand the definition of smart.

We should answer the question What is smart?, then observe the characteristics of

plants. After that, we will be able to take conclusion whether plants are smart or not.

Websters dictionaries define intelligence as the ability to cope with a new

situation or the ability to learn or to deal with new or trying situations.

(http://www.fortunecity.com/greenfield/clearstreets/84/intell.htm). If we see the

characteristics of plants, of course they have the ability to cope with new situations

(environmental changes). Plants are able to do adaptations in order that they can survive.

Plants make their own food (by processing inorganic molecules to be organic molecules

through photosynthesis), plants defend against the biological dangers (through anatomical

weapons, such as thorn, hairs, and sticks), plants produce toxic or unpalatable chemical to

protect themselves from biological dangers, plants are able to sense changes in

environment (such us, the forming of buds in summer to prepare for winter). These

several characteristics can proof that the plants are able to adaptations to give response to

their environment. Thus, the plants can cope with a new situations in environment.

Finally, it can be concluded that the plants are intelligent, since they have adaptively

variable behavior.

10.Identify the characteristics of the plant kingdom.Answer:

a. Plants are eukaryotic. It means that the cells of plants have nuclear membrane.b. Plants are multicellular. It means that the body of plants consist of much cells.c. Plants are producers, since they are photosynthetic autotrophic organisms.d. They can do sexual reproduction (pollination) and also asexual reproduction

(budding).


9/12

e. Plants do not do motility.f. The cell walls of plants are composed of cellulose.

11.Autotrophs are typically non-motile and heterotrophs are typically motile. Why didevolution favor this situation?

Answer: One of the aims of motility is to obtain food. Heterothrops are motile because

they should search out and trapping the food which are widely dispersed, since they can

not manufacture their own food (organic compound as the source of energy).

Meanwhile, plants are able to manufacture their own food through photosynthesis

process. In photosynthesis, the energy of light is trapped and converted into the cemical

bond energy of organic compounds such as sugar. Since the nutrients which are requiredby plants are omnipotent, there was never an evolutionary pressure for motility.

Thus, plants are adapted for harvesting dilute nutrients that occurs everywhere, and they

do not need to do motility.

12.Explain why leaves are broad and flat.Answer: The leaves are broad and flat to allow for efficient light harvest. The leaves are

broad to maximize surface area for light harvest and they are thin since light can not

penetrate too deeply into the leaf (the amount of light decreases exponentially with

distance).

Within the thin leaf, most chloroplasts are found in the upper layer of cells, the

palisade layer, which is the tissue layer just beneath the epidermis. Since the chloroplast

mostly found in palisade layer, it makes sense that the broad leaves will be able to

support photosynthesis, because it is able to increase the amount of light in any are of

leaf.


10/12

13.Compare animals and plants in terms of nutrients (type, concentration, location).Answer:

COMPARISON OF ANIMAL AND PLANT NUTRITION

NUTRIENT PLANT ANIMAL

Type Inorganic (CO2, H2O, ions) Organic (proteins,

carbohydrate, fats).

Concentration Dilute Concentrated

Distribution (Location) Omnipotent Localized

One of the main reasons for motility is to obtain food. Because the animals are not

able to make their own food, they are adapted for searching out and trapping widely

disperse, concentrated packets of food.

Meanwhile, plants are able to make their own food by processing inorganic

material to be organic materials. Since the nutrients required by plants are omnipotent,

there was never an evolutionary pressure for motility in plants. Accordingly, plants

must be adapted for harvesting dilute nutrients that occur everywhere in its environment.

14.Explain why plants are not limited by size.Answer: Plants are not limited by size because of their indeterminate growth and

architectural growth. Indeterminate growth is the process by which a plant continues to

grow and get larger throughout its life cycle. Thus, it allows the plant, especially root, to

grow into new areas. Meanwhile, architectural design means that the plant body is

constructed like a building. It is built of a limited number of units, each of which is

relatively independent of the others and that are united into a single structure.

This architectural growth and indeterminate growth give the plants the ability to colonize

and exploit new areas for resources.


11/12

15.Identify the specialized structures (and their function) that plants use forautotrophism.

Answer:

1. Chloroplast.It is used by plant as the organelle in which the photosynthesis occurs. Within the

chloroplast, the specialization was also required. There are three major area in the

chloroplast, those are the stroma, inner membrane, and inter-membrane space. Each

of these three regions is important for the functioning of photosynthesis. Electron

transfer reactions occurs in the inner membrane, the calvin cycle occurs in the

stroma, and the inter-membrane space is needed to generate the pH gradient across

the membrane that is important for photophosphorilation.

2. Broad and flat leaves.Leaves are the common place for photosynthesis. They are broad and flat to allow for

efficient light harvest.

3. CuticleA waxy coating (cuticle)over the outer cell layers (epidermis), which acts to limit the

amount of water loss from the leaf, as well as limiting the entry of disease organism

into the leaf.

4. StomataSmall openings in the surface of the leaf, known as stomata, whose size is regulated

by specialized pairs of guard cells. These small opening allow the entry of carbon

dioxide into the inner leaf structure and the release of oxygen and water vapor from

the leaf to its environment.

5. Palisade tissueIt is a layer of cells that contains large concentrations of chloroplasts. This layer lies

just underneath the upper epidermis and is the principal tissue involved in the

photosynthetic process.

6. Spongy tissueA loosely packed layer of cells (spongy layer) that allows free movement of gases to

the photosynthetic cells of the leaf.


12/12

7. Xylem and phloemThe evolution of vascular tissue, specifically phloem, permitted movement of the

result of photosynthesis from leaves to roots, fruits, and other tissues where required.

Meanwhile, the xylem permitted movement of water from the roots to the leaves.

andi citra pratiwi 091404170

Documents

Transcript of andi citra pratiwi 091404170