| 1.
Define the term energy.
Energy is the ability to do work. Organisms do work
to maintain themselves and grow.
2. Define the term metabolism.
Metabolism is the vast number of chemical reactions
that take place in a living organism.
3. Describe the four properties of living things.
Living organisms use energy to maintain themselves and grow. Living
organisms use energy to regulate their internal environments. Living
organisms sense and react to their external environment. Living organisms
reproduce to perpetuate their kind and pass their characteristics on
to their offspring.
Ingesting food ("eating") is not a property of all living
things. When was the last time you saw a tree eating a burger? Trees
and all other photosynthetic and chemosynthetic organisms make their
own food.
4. What are organic compounds?
Organic compounds are chemicals that contain atoms
of carbon, hydrogen, and usually oxygen. The ability to use energy to
make (or synthesize) organic compounds is an important characteristic
of living things.
5. What are the four main groups of organic molecules?
The four main groups of organic molecules are carbohydrates, proteins,
lipids, and nucleic acids.
6. What are carbohydrates? What are some examples of carbohydrates?
Carbohydrates are composed mainly of carbon, hydrogen,
and oxygen. Complex carbohydrates are made up of chains of simple sugars,
such as glucose. Carbohydrates store the energy that is captured during
photosynthesis. Sugars, including glucose, starches, cellulose, and
chitin are all examples of carbohydrates. Cellulose is a structural
molecule that is important in many organisms.
7. What are proteins? What are some examples of proteins?
Proteins are the most varied and complex organic compounds.
They contain carbon, hydrogen, oxygen, and nitrogen. They are made up
of chains of smaller subunits called amino acids. Examples of proteins
include enzymes and hormones. Hormones act as messengers to help different
parts of the body communicate, and enzymes speed up chemical reactions
within an organism.
8. What are lipids? What are some examples of lipids?
Lipids are organic compounds used by organisms for
energy storage. Fats, oils, and waxes are examples of lipids. Some marine
organisms also use lipids for coating their fur or feathers because
lipids repel water. Lipids also are useful in buoyancy because they
float and for insulation from the cold.
9. What are nucleic acids? What are some examples of nucleic
acids?
Nucleic acids store and transmit the basic genetic
information of all living organisms. Nucleic acids are made up of chains
of repeating subunits called nucleotides, which are simple sugars joined
to phosphorus- and nitrogen-containing molecules. Some examples of nucleic
acids are RNA (ribonucleic acid) and DNA (deoxyribonucleic acid). DNA
is the nucleic acid that stores genetic information.
10. Describe photosynthesis (in words), including its significance
to life.
Photosynthesis is the process by which plants, algae,
and some other organisms capture the sun’s energy and use it to
make glucose, a simple sugar (remember, sugars are carbohydrates). Some
of the glucose is converted into other organic compounds, which organisms
use as a source of energy.
11. Describe photosynthetic pigments and chlorophyll.
Photosynthetic pigments are chemicals that during photosynthesis
absorb solar energy. The most common photosynthetic pigment is chlorophyll,
which creates the bright green color characteristic of plants. Algae
often have additional photosynthetic pigments, which cause them to be
brown, red, or even black in addition to green.
12. Describe the chemical process of photosynthesis both in
words and with its chemical formula.
In a long series of enzyme-controlled reactions, the solar energy absorbed
by chlorophyll and other pigments is used to make glucose, with carbon
dioxide and water as the raw materials. The glucose is then used to
make other organic compounds. In addition, photosynthesis produces oxygen
gas, which is released as a by-product.
H20 ...+........ CO2 ------------------- > Glucose and O2
(water) (carbon dioxide) (with solar energy) ......(oxygen)
13. What are autotrophs? What are heterotrophs?
Autotrophs are organisms capable of photosynthesis—that
is they can obtain all of the energy they need for life from photosynthesis
and do not need to eat. Plants are the most familiar autotrophs on land;
in the ocean, however, algae and bacteria are the most important autotrophs.
Heterotrophs cannot produce their own food and must
obtain energy by eating organic matter that already exists. Animals
are heterotrophs.
14. Describe respiration (in words) and its significance to
life.
Both autotrophs and heterotrophs perform respiration to make use of
the energy stored in organic chemicals by photosynthesis. Respiration
is essentially the opposite of photosynthesis; sugars are broken down
using oxygen to release the energy stored in them and carbon dioxide
and water are given off.
15. What is the chemical formula for respiration?
Glucose + O2 --------------------- > CO2 .......and ....H20
.........(oxygen) (releases energy) (carbon dioxide) (water)
16. What is primary production?
Primary production is the net gain in organic matter
that occurs when autotrophs photosynthesize more than they respire.
This extra organic matter is used by the autotrophs to reproduce and
grow and, therefore, represents more food for animals and other heterotrophs.
Primary production can be measured in an ecosystem. Organisms that perform
primary production are called primary producers.
17. What are nutrients? What are the most important nutrients
in the ocean?
A nutrient is a raw material other than carbon dioxide
and water that is needed by an autotroph to produce organic matter during
photosynthesis. Nutrients include minerals, vitamins, and other substances.
The two nutrients needed by primary producers in the largest amounts
are nitrogen and phosphorus. The most important form of nitrogen in
the ocean is nitrate (NO3-1) and the most important form of phosphorus
is phosphate (PO4-3).
18. Describe and define the terms cell and organelles.
Cells are the basic structural unit of life. Organisms
are made of one or more cells. Cells contain all the molecules needed
for life. Cells are surrounded by a cell membrane, which isolates the
contents of the cell or cytoplasm from the outside world. There are
a number of important structures contained within the cytoplasm—including
the cell’s genetic material. If membranes surround these structures,
they are called organelles. Examples of organelles
include the nucleous, mitochondria, endoplasmic reticulum, chloroplasts,
and ribsomes.
19. What are the two types of cells?
The two types of cells are prokaryotic cells and eukaryotic
cells.
20. Describe prokaryotic cells. What types of organisms are
prokaryotes?
Prokaryotic cells are the most ancient type of cell.
They are simple and small and are distinguished by the absence of membrane-bound
organelles. Most prokaryotes are microscopic. The most well-known group
of prokaryotes is the bacteria.
21. Describe eukaryotic cells. What types of organisms are
eukaryotes?
Eukaryotic cells are more organized and complex than
prokaryotic cells. Various membrane-bound organelles do special tasks
within the cells; these include the nucleus (which contains the cell’s
genetic material), the mitochondria (where respiration takes place),
and, if the cells are part of a plant or other producer, the chloroplasts
(where photosynthesis takes place). Plants, animals, fungi, and many
other organisms are eukaryotes.
22. Compare unicellular and multi-cellular organisms.
One-celled organisms are unicellular. All prokaryotes
and some eukaryotes are unicellular. Most eukaryotes are multi-cellular—they
are made up of more than one cell.
23. What is “level of organization”?
The extent of specialization and organization with in a multi-cellular
organism is referred to as level of organization. For
example, groups of specialized cells that perform the same task may
be organized into more complex structures. This term may also be applied
to describe how individuals interact with each other at various levels
of complexity.
24. Describe the levels of organization within multi-cellular
organisms, in order of increasing complexity.
Cellular level: at this level, each cell is essentially
an independent, self-sufficient unit.
Tissue level: at this level, groups of cells that are
specialized for the same function are bound together. An example is
muscle tissue.
Organ level: at this level, tissues are organized into
structures that carry out specific functions. An example is the stomach.
Organ system level: Groups of organs work together
in cooperation. An example is the digestive system.
25. Describe the levels of organization among individuals,
in order of increasing complexity.
Individual level: a single organism.
Population level: groups of organisms of the same species
that occur together.
Community level: all the populations of different species
within a particular habitat.
Ecosystem level: a community or communities in a large
area, together with their physical environment.
26. What is a habitat?
A habitat is the natural environment where an organism
lives.
27. What are three challenges to life in the ocean habitat,
as discussed in the textbook?
Three challenges faced by organisms that live in the ocean habitat are
salinity, temperature, and surface-to-volume ratio.
28. Define the terms planktonic, benthic, and nektonic.
Planktonic is an adjective used to describe organisms
that drift in the ocean; those that can’t swim strongly enough
to move against the currents.
Benthic is an adjective used to describe organisms
that live on the bottom of the ocean.
Nektonic is an adjective used to describe organisms
that are strong swimmers; those that can swim against the currents.
29. Describe the process of diffusion.
Ions and molecules that are dissolved in water tend to move around randomly
just like water molecules do. When a crystal of salt dissolves in a
container of water, the resulting ions start out concentrated close
to the dissolving crystal but eventually spread out because of their
random movement. This process, called diffusion, results
in the flow of ions from areas of high concentration to areas of low
concentration.
30. If the concentration of sodium ions is higher in the water
surrounding a cell than it is within the cell, how will diffusion
occur? How does this present a problem for cells?
Sodium ions will move from the area of high concentration (the water)
to the area of low concentration (the inside of the cell) until the
concentration inside and out is the same.
Because many of the cell’s important molecules (such as ATP, amino
acids, and nutrients) are more concentration within the cell than in
the surrounding water, these important molecules tend to “leak”
out of the cell by diffusion.
31. What is a selectively permeable membrane? How does it solve
some of the problems of diffusion for a cell?
Cell membranes are selectively permeable; that is,
they block the passage of some of the common ions in seawater from entering
a cell and some of the common organic molecules in a cell from leaving.
This solves the problem of important molecules “leaking”
out of the cell by diffusion. However, water and other small molecules
can pass readily though the cell membrane.
32. What is osmosis? How does it affect cells?
Osmosis is a type of diffusion—it is the diffusion
of water across a selectively permeable membrane. Although ions in higher
concentration outside of cell can’t diffuse into a cell because
of its selectively permeable membrane, osmosis can create the same problem
for cells. If the concentration of an ion is higher outside of the cell,
water will leave the cell in order to balance out the difference in
concentration. This will cause the cell to shrivel. If, on the other
hand, the concentration of an ion is higher inside the cell, water will
diffuse into the cell in order to balance out the difference in concentration.
This will cause the cell to swell (and maybe even burst).
33. What is active transport? How do cells deal with osmosis?
Active transport is a process in which proteins in
the cell membrane pump materials in the opposite direction to which
they would move by diffusion. This allows cells to counteract osmosis
but it is an energy-intensive process that represents over one-third
of a cell’s total energy expenditure.
34. Preview: What are ions? What is salinity? What is a solute?
Ions are atoms or groups of atoms that have a negative
or positive charge. Salinity is the total amount of
salts dissolved in water. Salts are combinations of ions. Solutes
are ions, organic molecules, or anything else that is dissolved in a
solution (such as water).
35. What are two strategies that marine organisms use to regulate
salt and water balance within their cells and bodies?
Osmoconformers have an internal salinity that is the
same as the surrounding water and if the external salinity changes so
does the internal salinity of the organism. Typically, they can only
tolerate small changes in salinity before osmosis causes the cells irreparable
damage. However, this strategy conserves energy.
Osmoregulators control their internal concentrations
to avoid osmotic problems. One way is by adjusting the concentration
of solutes in their body fluids so that it matches that of the water
outside. Other marine organisms maintain blood concentrations that are
different than the surrounding water.
36. Give two examples of how some osmoregulators control their
internal concentrations of solutes.
Sharks increase or decrease the amount of urea in their blood so that
the total amount of dissolved materials in their blood matches that
of the surrounding water.
Most marine fishes have body fluids that are more dilute than sea water
and they lose water by osmosis. They replace this lost water by drinking
sea water and excreting the salts but keeping the water. As a result
they produce very concentrated urine in small amounts.
Marine birds and reptiles and some marine plants have special cells
or glands to ride themselves of excess salt.
37. How do most organisms deal with temperature?
Organisms are greatly affected by temperature. Metabolic rates proceed
faster at higher temperatures and slow down dramatically as it gets
colder. Most marine organisms are adapted to live in particular temperature
ranges, and as a result temperature plays a major role in determining
where different organisms are found in the ocean.
38. Define the terms ectotherm and poikilotherm.
Ectotherms lose any heat they generate through their
metabolism to the environment. Poikolotherms are the
same temperature as their surrounding environment and their metabolic
rates change as the temperature changes. All ectotherms are poikolotherms.
Almost all fishes are both ectotherms and poikolotherms.
39. Define the terms endotherm and homeotherm.
Endotherms use their metabolic heat to raise their
body temperature above that of their surroundings. Homeotherms
are able to keep their internal temperature more or less constant, even
when the temperature outside varies considerably. Some large, fast fishes
(like tunas and sharks) as well as mammals and birds are endotherms
and homeotherms.
40. Why is surface-to-volume ratio an important consideration
for life?
Organisms exchange (take into and out of their systems) nutrients, waste
products, and gases. The rate and amount of this exchange is determined
by surface area of the organism. More precisely, it is the amount of
surface area relative to the total volume of the organism that determines
how much “stuff” can go in and out of an organism. In other
words, the surface-to-volume ratio determines how rapidly heat and materials
flow in and out.
The surface-to-volume ratio is determined by the size of the organism.
As organisms grow larger, their volume increases FASTER than does their
surface area. So, small organisms have larger surface-to-volume ratios
than do larger organisms. Smaller organisms, especially single-celled
ones, therefore can rely on diffusion across their surfaces to exchange
materials. Larger organisms, especially multi-cellular ones, may develop
supplementary mechanisms, such as respiratory and digestive systems,
to exchange materials.
41. Why is perpetuating life an important characteristic of
life?
Any life that failed to replace itself with new individuals of its own
kind will soon vanish from the planet. It is only through reproduction
that a species ensures its perpetuation.
42. What is heredity?
Heredity is the transfer of genetic information from
one generation to the next.
43. What are the two dominant modes of reproduction?
The two modes of reproduction are asexual and sexual reproduction.
44. Describe asexual reproduction and give three examples.
Asexual reproduction occurs when a single individual
reproduces without the involvement of a partner. All of the offspring
are clones or exact copies of the parent. Asexual reproduction by cell
division is the primary way that single-celled organisms reproduce.
Multi-cellular organisms also reproduce asexually. Fission, whereby
a parent organism splits in half into two offspring, is an example of
asexual reproduction. Budding, whereby the parent organism develops
small growths or buds that break away and become separate organisms,
is another example. Many plants reproduce asexually by sending out runners
that grow into new plants—this is often called vegetative reproduction.
45. Describe sexual reproduction.
Sexual reproduction occurs when new offspring arise
from the union of two separate cells called gametes—the gametes
usually come from different parents. Most multi-cellular and some unicellular
organisms reproduce asexually.
46. Why do marine organisms display a variety of reproductive
strategies?
Different strategies work best for different organisms, each of which
may be a different size, live in a different environment, etc.
47. Describe broadcast spawning.
Broadcast spawning is a reproductive strategy used
by many different marine organisms, including some types of fishes and
invertebrates. These species release millions of eggs and sperm into
the water, where fertilization takes place. They invest lots of energy
to create these millions of gamete cells but no energy on caring for
their young. In comparison, other species produce very few gametes (and
therefore zygotes), but expend a large amount of energy caring for those
few offspring.
48. Describe the process of natural selection.
Organisms vary in their abilities to be successful in their environment
and to reproduce and create offspring. Those organisms that are best
adapted to their environment and successfully reproduce will, on average,
leave behind more offspring than other organisms.
49. What is evolution?
Evolution is a change in the genetic makeup of a species
over time.
50. How does natural selection relate to the theory of evolution?
The best-adapted organisms in a population will not only leave behind
more offspring but they will pass on their favorable characteristics
to their offspring through the exchange of genetic material during sexual
reproduction. These favorable traits over time will become more common
in the population. This leads to a change in the genetic makeup of the
species over time—evolution.
51. What is biological nomenclature?
Biological nomenclature is a two-name system that identifies
organisms biologically (as opposed to the two name system of first and
last name that identifies people socially!). Each species has a genus
and species name. The genus is a group of very similar species. It is
customary to italicize both the species and genus names and to capitalize
only the genus name.
52. Use dogs, wolves, and coyotes to give an example of biological
nomenclature.
Dogs, wolves, and coyotes are all share the same genus: Canis. Each
is a separate species, distinguished by their species names. Dogs are
Canis familaris, wolves are Canis lupus,
and coyotes are Canis latrans.
53. Why do scientists use biological nomenclature to name species
instead of using common names (like “dog”)?
Common names are not very precise—many different species may have
the same common name. This can lead to lots of confusion. Scientists
use biological nomenclature because each species has just one name—therefore
there is no confusion. [Except in how to pronounce the names!]
54. What is phylogeny?
Phylogeny is sharing a common evolutionary history
… it is a method of indicating “relatedness.”
55. What are the three domains of life? How are they different?
How are they alike?
The three domains are the Domain Archaea, Domain
Bacteria, and Domain Eukaryota. The Domain
Archaea includes prokaryotic, ancient bacteria. The Domain Bacteria
includes prokaryotic bacteria. The Domain Eukaryota includes all the
eukaryotic organisms.
56. What are the four kingdoms within the Domain Eukaryota?
The four kingdoms within the Domain Eukaryota include the familiar kingdoms
of Plantae and Animalia as well as
the Kingdom Fungi (which are multi-cellular, somewhat
plant-like organisms) and the Kingdom Protista (which
includes a varied groups of both unicellular and multi-cellular organisms,
some of which are plant-like and some of which are animal-like and some
of which are both!).
57. List the 8 taxonomic levels (in order of most inclusive
to least inclusive) used by scientists to group organisms by their
degree of relatedness.
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species [There
are several cutsie saying to help you remember this. The one I learned
as a kid is "Darn King Philip Came Over From Germany Saturday]
Critical
Thinking Questions
58. During the day, primary producers like seaweeds carry out both
photosynthesis and respiration, but at night, when there is no light,
they perform only respiration. Small, isolated tide pools on rocky
shores are often inhabited by thick growths of seaweeds. Would you
expect the amount of oxygen to differ between night and day? How?
Oxygen dissolved in the water sharply decreases at night because the
seaweeds carry out respiration but no photosynthesis. Oxygen thus may
become limiting at night.
59. Is breathing the same thing as respiration?
No, breathing is the way that some multi-cellular organisms bring oxygen
to the organ system responsible for respiration (the respiratory system)
and take away the by-product of respiration (carbon dioxide). Respiration
itself takes places in every cell of every living organism.
60. Where in the ocean would you expect rates of primary production
to be highest? Lowest?
Primary production is the net gain in organic matter that occurs when
autotrophs photosynthesize more than they respire. This happens in areas
that are most favorable for photosynthesis: lots of sunlight (summer
time or close to the equator), clear water (so that the sunlight penetrates
the water), and nutrient-rich areas (where there is upwelling of nutrients
from deeper water or runoff of nutrients from land). Some of the most
productive areas in the ocean are upwelling areas off the coasts of
continents with steep continental shelves and polar waters during the
summertime (when daylight lasts 24 hours). Some of the least productive
areas in the ocean are in the middle of large gyres where the water
doesn’t circulate much and is depleted in nutrients and oxygen.
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