Life in the Sea

Carbohydrate Elements: C, H, O Function: nutrients for cell/ energy ex: sugar (simple) starch (complex)

Carbohydrate Monomer: monosaccharide (single units of sugar C6H12O6) Carbon + water (H2O) 2:1 Hydrogen: Oxygen -ose (sugar) Glucose, fructose, galactose, amylose 1 3 2 5 12 4 7 5 9 6 11 3 6 8 10 4

Carbohydrate Disaccharide: two monomers put together ex: maltose, lactose, sucrose

Carbohydrate Polysaccharides ex: starch (potato, pasta, rice, etc.) “many” Thousands of monomers linked together ex: starch (potato, pasta, rice, etc.)

Carbohydrate: Polysaccharides Cellulose plant cell walls Indigestible Chitin exoskeletons (shells) Also found in fungi cell walls

Lipids Function: Energy storage ex: fat, wax, steroids, cell membranes Elements: C, H, O Function: Energy storage ex: fat, wax, steroids, cell membranes

Lipids No monomers (no repeating of single units) hydrophobic Functional group: carboxyl group

Lipids: Fats One glycerol Fatty acids (carboxyl group + hydrocarbon chain) Soap made from fatty acids

Lipids: Saturated Carbon chain with only single covalent bond excludes double bond in carboxyl group Hard at room temperature

Lipids: Unsaturated Carbon chains with one (unsaturated) or more (polyunsaturated) double bonds excludes double bond in carboxyl group “Kink” Soft at room temperature

Lipids: Phospholipids Polar, hydrophilic head Non-polar hydrophobic tails Found in cell membranes

Protein Characteristics/Functions Antibodies for defense Enzymes for catalyzing reactions Made of 20 different amino acids movement

Proteins Monomer: amino acids Functional group: Carboxyl group Amino group Central carbon “R” group (variable) Determines unique physical and chemical characteristics

Protein Structure Effected by temperature and pH Shape determines its function Folds in proteins aided by chaperone proteins

Nucleic Acids Elements: C, H, O, N, P Function: genetic material/energy molecule ex: DNA, RNA, ATP

Monomer: Nucleotide Phosphate group Sugar: Nitrogen Base: ex: Deoxyribose Nitrogen Base: examples: Adenine Thymine Cytosine Guanine

The Need for Classification Three reasons for classifying organisms: 1. It helps identify the relationships between organisms. 2. It requires scientists to clearly identify key characteristics of each organism. 3. It avoids confusion. Common names differ with cultures. Scientists in the US and Japan can identify exactly what they are both talking about by using the species’ Latin name. Latin is a dead language

Classification Taxa An organism’s scientific name represents two taxa. They are: 1. Species – is the most specific of the taxa. Species is usually considered to be a group of organisms that can reproduce together. 2. Genus – is the taxon above species. Genus grouped species are considered to be closely related, i.e., there are 34 species of reef shark belonging to genus Carcharhinus. Species are identified by referring to both the genus and the species, with the genus capitalized and the species name in lower case.

There are seven main taxa into which organisms are classified; from the general to specific: Kingdoms are groups of phyla (plural of phylum). Phylum (or division) is a group of classes. Classes are groups of related orders. Orders are groups of related families. Families are groups of genera that share characteristics. Genus (plural genera) groups species that are closely related. Species is the Latin name for an individual organism.

Determining Taxa How organisms are classified: Originally by using anatomical features. The prevailing view now is that taxonomy generally reflects theoretical evolutionary relationships. Classifying by anatomical features remains an important classification method. However, the study of genetics has become more important.

A common problem taxonomists have in classifying organisms is that some organisms don’t fit neatly into defined classifications. An organism can have characteristics that fit in one and others that separate it from that same classification. The answer is to insert intermediate classification levels. By assigning superlevels to create new higher divisions within a classification. By assigning sublevels to create lower divisions within a classification.

Six - Kingdom System and Three - Domain System Until recently taxonomists recognized five kingdoms: kingdom Monera, kingdom Protista, kingdom Fungi, kingdom Plantae, and kingdom Animalia. The six-kingdom system divides kingdom Monera into two new kingdoms: kingdom Eubacteria and kingdom Archaebacteria.

The three-domain system method is based on genetic and biochemical research. Domain Archaea is composed of organisms scientists think evolved first. In this system domain Eukarya includes the Protista, Plantae, Fungi and Animalia kingdoms.

Old and Simple Prokaryotes are among the most important of the primary producers in the ocean. They don’t have the same complex internal membrane structure. They lack chromosomes or a nucleus. Instead they have a ring of DNA or RNA. They don’t have mitochondria and lack chloroplasts. They are structurally simple – molecules are surrounded by a membrane and cell wall. They are believed to be the oldest types of organisms – archaea originated 3.5 billion years ago. Scientists think that the process of photosynthesis began with cyanophytes of domain Bacteria, an early prokaryote.

Archaea and Bacteria Domain Archaea and domain Bacteria are best known for being extremophiles – living in environments that are inhospitable to most life. Bacteria can do things no other known organisms can do: Certain species can create organic nitrogen compounds by fixing inorganic nitrogen from the air – an essential element of life. The most important bacteria are in the phylum Cyanophyta. Scientists think that these bacteria are crucial to life because: Photosynthesis evolved in the cyanophytes. Cyanophytes were the primary organisms that created the oxygen in the atmosphere. Cyanophytes are among the bacteria responsible for nitrogen fixation. Also, some scientists think we presently underestimate the role cyanophytes play in primary productivity. Their pigments can contribute to the color of other organisms.

A Broadly Applied Name Algae is defined by taxonomists as those organisms that belong in one of seven specific phyla or divisions in kingdom Protista. 1. Chlorophyta 2. Rhodophyta 3. Phaeophyta 4. Dinophyta 5. Bacillariophyta 6. Euglenophyta 7. Chrysophyta

Phylum Bacillariophyta – The Diatoms Phylum Bacillariophyta is made up of diatoms, the most productive phytoplankton. These primary producers are a widely diverse group. Between 5,000 to 50,000 species may make up this phylum. Diatoms are larger than prokaryotes – from 20 to 80 microns across. They have two-part silicon shells in an amazing array of shapes. They are photosynthesizers that are relatively dormant during the winter months. Diatoms reproduce quickly when sunlight levels rise and are thought to account for 25% of all the photosynthetic biomass on Earth.

Phylum Dinophyta – The Dinoflagellates Dinoflagellates make up phylum Dinophyta (also called phylum Pyrrophyta or phylum Dinoflagellata). In size they are 30 to 150 microns across and are the second most productive group of primary producers. Symbiodinium are particularly important autotrophic dinoflagellates. They live within the zooxanthellate coral polyps. They provide their host with food via photosynthesis. In return Symbiodinium get nitrogenous wastes from the coral. These are the only coral that build massive coral reefs. Without Symbiodinium, coral could not exist as we know it. Without coral and coral reefs there would not be the unique organisms that make up the world’s most productive and beautiful ecosystems.

Phylum Chlorophyta – Green Algae Phylum Chlorophyta is made up of the macro algae – a term that applies to several algae phyla, but refers to multicellular species like seaweed. They share the same green color as land plants. Both green algae and land plants have: Chlorophyll a – a pigment directly involved with photosynthesis. Chlorophyll b – assists chlorophyll a in capturing light for use in photosynthesis. Chlorophyll a and b absorb different colors of light, thus using light more efficiently. Scientists think the presence of chlorophyll a and b has evolutionary significance. It may indicate that land plants evolved from green algae. Green algae and land plants also have other pigments in common and have cell walls made of cellulose.

Phylum Rhodophyta – Red Algae Red algae is red because they have pigments called phycoerythrins which give it their color. This pigment has not been found in any other eukaryote, though it does exist in cyanophytes. Phycoerythrins allow some red algae to live deeper than any other algae – some as deep as 200 meters (656 feet). Red algae also has chlorophyll a, but not b. Red algae is important to coral reefs because it is the cement that holds the coral reefs together. Red algae species that live on coral reefs secrete a calcium carbonate shell. Their secretions bond coral colonies and debris together which in turn holds the reef together.

Phylum Phaeophyta – Brown Algae Phylum Phaeophyta (brown algae), is more structurally complex. Many brown algae species have: Holdfasts – anchor the algae to the bottom. Leathery stipes – provide support like plant stems, but with no vascular system. Blades – equivalent of leaves. Pneumatocysts – gas filled float structures that lift the algae off the bottom and keep the blades close to the surface and sun. Kelp is the largest of the brown algae. Kelp is important because it is the foundation for many temperate coastal ecosystems.

Bioluminescence light that is biologically produced and is caused when a light-emitting molecule, called luciferin, is mixed with an enzyme, luciferase, in the presence of oxygen. Bioluminescence is actually quite common and almost all taxonomic groups of animals, and many plants, have some members that bioluminesce. Planktonic dinoflagellates and bacteria are some of the most abundant creators of this biological light

Reasons for bioluminescence vary depending on the organism escaping predators obtaining prey Attraction advertising