fundamentals of biology shipley’s marine biology

Fundamentals of BiologyFundamentals of Biology

Shipley’s Marine BiologyShipley’s Marine Biology

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

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.


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


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.

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.


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

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.

Energy and Life

Some of the carbohydrates made by

photosynthetic organisms are converted into other types of molecules such as:

Proteins Lipids Nucleic acids

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

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

Energy and Life

All living organisms can be divided into two

basic groups based on cellular composition:

1. Prokaryotic2. Eukaryotic

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

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

Types of 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

Example Organelles in Eukaryotic Organisms

Atom – fundamental unit of all matter

Molecule – two or more atoms chemically joined together

Levels of Organization in Living Organisms

Organelle – specialized features of cells

Cell – basic unit of life


Tissue – group of cells functioning as a unit

Organ – many tissues arranged into a structure with a specific purpose in an organism


Organ system – group of organs that work

together

Whole organism (individual)


Population – group of organisms of the same

species occurring in same habitat


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


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.

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

Diffusion and Osmosis

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

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

Regulation of Solute/Water Balance

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.

Homework Assignment

Ectotherms

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

Temperature Control

Endotherms

– 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

Temperature Control

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

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


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


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


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


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


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.

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.


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.


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.

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

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).

Taxonomy

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.

Phylogenetics

fundamentals of biology shipley’s marine biology

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