1. Fundamentals of Biology
Module 2: Life in the Sea
Fundamentals of Biology

2. The Essential Building Blocks of Life
Just like water is a molecule, there are other molecules important to life.
Four organic (contain carbon, hydrogen and oxygen) molecules make up living organisms:
Carbohydrates
Proteins
Lipids
Nucleic acids

3. The Essential Building Blocks of Life
Carbohydrates:
Made of carbon, hydrogen and oxygen at a 1:2:1 ratio (example: glucose is C6h12O6).
Most carbohydrates are used for energy for organisms.
Some are used to store energy to be used later (like starch found in plants and some algae.
Some are used in structure such as chitin found in the shells of some animals (like crabs, lobsters and shrimp) or cellulose found in plants.

4. The Essential Building Blocks of Life
Proteins:
Composed of smaller units known as amino acids
Enzymes are specialized proteins necessary for chemical reactions in an organism
Some proteins are hormones that act as chemical messengers within an organism
Others can be used in structure, immunity, internal transport among other duties

5. The Essential Building Blocks of Life
Lipids:
Lipids are mainly hydrophobic (do not mix with water – remember the saying that oil and water don’t mix).
Due to this principle, many marine organisms use a coating of lipid to cover fur or feathers which provides an insulating layer.
Some also have a layer of lipid (fat) underneath the skin for insulation.
Many lipids are used for energy storage within an organism.
They can also be used for internal structure or as hormones.

6. The Essential Building Blocks of Life
Nucleic Acids:
Made of smaller units called nucleotides.
DNA and RNA are nucleic acids.
DNA is the molecule of heredity; it provides the instructions for making every part of an organism.
RNA helps with this duty in multiple ways.

7. Energy and Life
Many organisms use sunlight to drive the process of photosynthesis.
In photosynthesis, plants, algae and other autotrophs use pigments to capture the energy in sunlight.
This energy is used to build carbohydrates.
The source of carbon for building carbohydrates is carbon dioxide; oxygen is released as a by-product

9. Energy and Life
Whether an organism makes their own carbohydrates (autotrophs) or gets carbohydrates by eating other organisms (heterotrophs), they still must break down the carbohydrates within their cells for energy.
This process is known as cellular respiration.
Respiration consumes oxygen and produces carbon dioxide and water as by-products.

11. Energy and Life
Some of the carbohydrates made by photosynthetic organisms are converted into other types of molecules such as:
Proteins
Lipids
Nucleic acids

12. Energy and Life
When these autotrophs make more energy than they can use, the excess is called primary production
Organisms responsible for this primary production are called primary producers
Marine organisms are a major source of worldwide primary production

13. Energy and Life
Marine organisms require nutrients to convert carbohydrates to other types of molecules
These nutrients can include minerals, vitamins and even raw elements
Ex: silica is required to make the shell of some organisms

15. Types of Organisms
All living organisms can be divided into two basic groups based on cellular composition:
Prokaryotic
Eukaryotic

16. Types of Organisms Prokaryotic Organisms: Lack a nucleus
Posses ribosomes
Contain a circular ring of DNA
Some may also have plasmids, extra pieces of DNA
Cell wall is normally present
May have a flagellum
Unicellular

18. Types of Organisms Eukaryotic Organisms
Possess DNA enclosed inside a nucleus
Posses many specialized organelles (look at organelles in Fig. 4.8)
Eukaryotic organisms can be unicellular or multicellular

20. Example Organelles in Eukaryotic Organisms
Mitochondria- site of cellular respiration
Golgi complex and endoplasmic reticulum- manufacture, package and transport cellular products such as proteins (Vesicles – transport things from one place to another.)
Ribosomes- manufacture proteins
Chloroplasts- site of photosynthesis
Vacuole- storage of water and nutrients
Centrioles- assist in movement of chromosomes during cellular reproduction

21. Levels of Organization in Living Organisms
Atom – fundamental unit of all matter
Molecule – two or more atoms chemically joined together

22. Levels of Organization in Living Organisms
Organelle – specialized features of cells
Cell – basic unit of life

23. Levels of Organization in Living Organisms
Tissue – group of cells functioning as a unit
Organ – many tissues arranged into a structure with a specific purpose in an organism

24. Levels of Organization in Living Organisms
Organ system – group of organs that work together
Whole organism (individual)

25. Levels of Organization in Living Organisms
Population – group of organisms of the same species occurring in same habitat

26. Levels of Organization in Living Organisms
Community – all species that exist in a particular habitat (ex: all the organisms on a coral reef)
Ecosystem – combination of the community and the physical environment

27. Diffusion and Osmosis
Solutes (substances dissolved in water) will move from areas where they are more concentrated to an area where they are less concentrated
This movement is called diffusion
Movement of water from an area where it is more concentrated to an area where it is less concentrated through a semipermeable membrane is called osmosis.

29. Diffusion and Osmosis
Since marine organisms live in a very solute-rich environment, they have a tendency to gain solutes and lose water
This can result in the death of cells if the water loss/solute gain is significant
These organisms must find ways to deal with this diffusion and osmosis

30. Regulation of Solute/Water Balance
Osmoconformers-
Do not attempt to control solute/water balance
Their internal concentration varies as the salinity in the water around them changes
Most can only tolerate a very narrow range of salinity

31. Regulation of Solute/Water Balance
Osmoregulators
These organisms control their internal concentrations
Can generally tolerate a wider range of salinities than osmoconformers
This can be done in a variety of ways such as secreting very little urine or using specialized glands to secrete salts as examples

33. Homework Assignment Go to www.cellsalive.com/
In the left-hand column labeled “Interactive,” click “Puzzles”
On the “Cells Alive! Puzzle Page,” complete both “Animal Cell” and “Plant Cell” Jigsaw puzzles.
Upon completing the puzzle, right click the mouse, and click “PRINT”.
On the same page, under “Word Puzzles,” complete “Cell Structure #1” and “Cell Structure #2.”
Again, upon completing each puzzle, print finished puzzle.

34. Temperature Control Ectotherms Poikilotherms
Generate body heat metabolically, but cannot maintain constant internal body temperature
Examples: snakes, lizards, frogs, insects
Poikilotherms
Body temperature mimics the surrounding environment. They do not use their metabolisms to heat or cool themselves.
Many ectotherms are poikilotherms.
Examples: fish, reptiles

35. Temperature Control Endotherms Homeotherms
Generate body heat metabolically and body temperature does not match the temperature of the surrounding environment
All birds and mammals
Homeotherms
These organisms retain metabolic heat and can control metabolism to maintain a constant internal temperature
Homeotherms are endotherms

36. Modes of Reproduction Asexual reproduction
Does not involve mating of two individuals
Young are produce by a single parent organism
The young produced are genetically identical to the parent

37. Modes of Reproduction Examples of Asexual Reproduction
Fission – the splitting of one organism into two smaller organisms of equal size
Budding – the organism develops buds (small clones) that eventually break off and become another organism
Vegetative reproduction – a plant reproduces new individuals by sending an underground stem (rhizome) sideways from which new plants will sprout

38. Modes of Reproduction Sexual reproduction
Normally involves two individuals
Parent individuals produce gametes (eggs or sperm) that unite to produce a new, genetically unique individual
Ovaries are the organs that produce eggs
Testes are the organs that produce sperm

39. Modes of Reproduction
Many marine organisms release their eggs and sperm directly into the water, this is known as broadcast spawning.
For broadcast spawning to be effective, millions of gametes must be released into the water at roughly the same time to ensure fertilization will occur
Many broadcast spawning species time the release of their eggs to tides, moon phase, water temperature, etc. to ensure success

40. Modes of Reproduction
Other marine organisms rely on internal fertilization, where a copulatory organ is used to insert sperm directly into the female’s reproductive tract
This method requires contact between parent individuals, but less gametes are required for success

41. Modes of Reproduction
Hermaphrodites – individuals that have male and female reproductive tissues either simultaneously or at different phases during the life. Examples:
Protandry- an individual spends the first portion of the life as a functional male then becomes a female later in life after some cue initiates the change
Protogyny- an individual spends the first portion of the life as a functional female then becomes a male later in life after some cue initiates the change

42. Evolution and Natural Selection
Evolution is defined as a change in the genetic make-up of a population over time
In the wild, any genetically derived traits (such as faster swimming or above-average intelligence) can give one individual survival advantage over others in his/her population.

43. Evolution and Natural Selection
These advantages can be translated into reproductive advantage as well.
If one organism is better survivor, more of their gametes will make it into the next generation in a population.
Those individuals that are less advantaged may not survive to reproduce or will reproduce less.
This is known as natural selection.

44. Evolution and Natural Selection
Natural selection therefore strengthens the gene pool of a species by eliminating less advantageous traits through lack (or reduction) of reproductive events in these individuals.

45. Taxonomy Taxonomy is the science of classifying and naming organisms.
This classification is done by a variety of methods including DNA and protein analysis, comparing embryos, looking at the fossil record and comparing internal and external body structures.

46. Taxonomy
Taxonomy uses several levels of classification shown below from the largest (most species inclusive) to the smallest (only one species):
Domain  Kingdom  Phylum  Class  Order  Family  Genus  Species

48. Taxonomy
There can be millions of different organisms in a domain or kingdom, while a species by definition is just one type of organism.
So, what defines a species? Common characteristics and the ability to breed successfully with other members of their species (biological species concept)
For example, there are 7 species of flounder (fish) that exist in the southeast U.S. No matter how much they look alike, they cannot breed with each other and produce viable (functionally reproductive) offspring (reproductive isolation).

49. Phylogenetics
Phylogenetics is defined as the study of evolutionary relationships (relatedness) in organisms.
Biologists may use many factors to determine the relatedness of organisms such as structure, reproductive patterns, embryological or larval development, fossils, behavior or DNA/RNA.