Shark embryo, Squalus acanthias

FundamentalsFundamentalsof of

BiologyBiology

What does it mean to be alive??What does it mean to be alive??

• You may find that your definition, or view, of You may find that your definition, or view, of life differs radically from your neighbor’s.life differs radically from your neighbor’s.

• You wouldn’t be alone there. Most You wouldn’t be alone there. Most scientists can’t agree on it either!scientists can’t agree on it either!

• Today’s material will cover the basics of Today’s material will cover the basics of biology. biology.

What Scientists What Scientists DoDo Agree Upon Agree Upon

• Life uses energy for metabolismLife uses energy for metabolism

• Life maintenances itself (homeostasis).Life maintenances itself (homeostasis).

• Life growsLife grows

• Life reproducesLife reproduces

• Life reacts to changing conditionsLife reacts to changing conditions

• Life finds a way!!Life finds a way!!

What does it take?What does it take?

• If you are trying to determine what it takes If you are trying to determine what it takes to be alive what would you do?to be alive what would you do?

• WaterWater would be a good starting point. would be a good starting point.

• Most organisms are composed largely of Most organisms are composed largely of water.water.

Where to go next?Where to go next?

• Organic molecules also play a major role Organic molecules also play a major role in life processes. in life processes.

• Organic moleculesOrganic molecules are those which are those which contain a source of carbon (except COcontain a source of carbon (except CO22

which is still considered inorganic), which is still considered inorganic), hydromen, and oxygen.hydromen, and oxygen.

• Most of these simple Most of these simple organic moleculesorganic moleculesare organized into moreare organized into morecomplex moleculescomplex moleculessuch as proteins, such as proteins, carbohydrates, carbohydrates, and lipids (fat).and lipids (fat).

• This is done in order to This is done in order to manipulate energy storedmanipulate energy storedwithin the molecules.within the molecules.

Just imagine how much energy is stored in this whaleJust imagine how much energy is stored in this whaleblubber (fat). blubber (fat).

• Conversely, equal Conversely, equal amounts of energy may amounts of energy may be stored within the be stored within the cellulosecellulosewalls of this giant kelp in the formwalls of this giant kelp in the formof of carbohydratescarbohydrates (sugar). (sugar).

• Carbohydrates are common in Carbohydrates are common in the marine environment for energy the marine environment for energy and for structure.and for structure.

• They are also found inside andThey are also found inside andoutside of animals (outside of animals (chitinchitin in shells). in shells).

•Other organic compounds of Other organic compounds of great importance are great importance are proteins.

•Proteins consists of Proteins consists of amino acids which amino acids which contain nitrogen.contain nitrogen.

• Proteins are used as Proteins are used as building blocks for building blocks for tissues such as tissues such as muscles and nerves.muscles and nerves.

•They are also used for They are also used for hormones…hormones…

……and even antifreeze!and even antifreeze!

Other necessities…Other necessities…

• In addition to proteins, In addition to proteins, carbs., and lipids, carbs., and lipids, organisms rely on organisms rely on DNA, DNA, RNA, and ATPRNA, and ATP to transfer to transfer genes, build proteins, and genes, build proteins, and store energy, store energy, respectively.respectively.

• ATP is extremely ATP is extremely important because it important because it serves as “energy serves as “energy currency” for most cells.currency” for most cells.

Most energy used by organisms originates from photosynthesis.Most energy used by organisms originates from photosynthesis.

• PhotosynesisPhotosynesis makes it makes it and and respirationrespiration takes it!! takes it!!

• Each process is Each process is essentially the reverse of essentially the reverse of the other.the other.

Photosynthesis and respirationPhotosynthesis and respirationcombine to facilitatecombine to facilitateprimary production.primary production.

Primary producers Primary producers are are photosynthetic organisms forphotosynthetic organisms forthe most part.the most part.

Each relys on Nitrates (NOEach relys on Nitrates (NO33-1-1),),

phosphates (POphosphates (PO44-2-2), and ), and

occasionally silica (SiOoccasionally silica (SiO22). ).

Cells, or the basic unit Cells, or the basic unit of life, contain a nucleus, of life, contain a nucleus, and various cellular and various cellular organelles which carry organelles which carry out cell specific functions.out cell specific functions.

In addition to the In addition to the organelles listed certain organelles listed certain bacteria also contain bacteria also contain motility structures called motility structures called flagella or cilia.flagella or cilia.

Sometimes, all you need in life is one cell, especiallySometimes, all you need in life is one cell, especiallyif you’ve got 10,000 buddies just like yourself!!if you’ve got 10,000 buddies just like yourself!!

(The first labor unions???)(The first labor unions???)

Challenges to life!Challenges to life!

IntroductionIntroduction

• Maintaining steady-state equilibrium in the Maintaining steady-state equilibrium in the internal environment of aquatic and marine internal environment of aquatic and marine organisms is challenging.organisms is challenging.

• Much is done involuntarily (hormones, enzymes, Much is done involuntarily (hormones, enzymes, osmoregulation, etc.) so little physical action is osmoregulation, etc.) so little physical action is required, however…required, however…

• ““Pick-up-and-move” still an option!Pick-up-and-move” still an option! (Poor environment.)(Poor environment.)

DefinitionsDefinitions

• HomeostasisHomeostasis = maintaining steady state = maintaining steady state equilibrium in the internal environment of an equilibrium in the internal environment of an organismsorganisms

• Solute homeostasisSolute homeostasis = maintaining equilibrium = maintaining equilibrium with respect to solute (ionic and neutral solutes) with respect to solute (ionic and neutral solutes) concentrations (i.e. salts)concentrations (i.e. salts)

• Water homeostasisWater homeostasis = maintaining equilibrium = maintaining equilibrium with respect to the amount of water retained in with respect to the amount of water retained in the body fluids and tissuesthe body fluids and tissues

Osmoregulation in different Osmoregulation in different environmentsenvironments

• Challenge to homeostasis depends onChallenge to homeostasis depends on

– Solute concentration of body fluids and Solute concentration of body fluids and tissues…tissues…

– ……concentration of environmental solutesconcentration of environmental solutes

• marine: ~34 ppt salinity = 1000 mosm/lmarine: ~34 ppt salinity = 1000 mosm/l• freshwater: < 3 ppt salinity = 1 - 10 mosm/lfreshwater: < 3 ppt salinity = 1 - 10 mosm/l

Osmoregulation in different Osmoregulation in different environmentsenvironments

• Each species has a range of environmental Each species has a range of environmental osmotic conditions in which it osmotic conditions in which it cancan function: function:– stenohalinestenohaline - tolerate a - tolerate a narrow rangenarrow range of of

salinities in external environment salinities in external environment – euryhalineeuryhaline - tolerate a - tolerate a wide rangewide range of salinities of salinities

in external environmentin external environment• short term changes: estuarine - 10 - 32 ppt, short term changes: estuarine - 10 - 32 ppt,

intertidal - 25 - 40intertidal - 25 - 40• long term changes: diadromous fishes long term changes: diadromous fishes

(salmon)(salmon)

Four osmoregulatory strategies in fishesFour osmoregulatory strategies in fishes

1. Isosmotic (nearly isoionic, osmoconformers)1. Isosmotic (nearly isoionic, osmoconformers)

2. Isosmotic with regulation of specific ions2. Isosmotic with regulation of specific ions

3. Hyperosmotic (fresh H3. Hyperosmotic (fresh H220 fish)0 fish)

4. Hyposmotic (salt H4. Hyposmotic (salt H22O fish)O fish)

Osmoregulation StrategiesOsmoregulation Strategies

OsmoconformingOsmoconforming (no strategy) Hagfish internal (no strategy) Hagfish internal salt concentration = seawater. However, since salt concentration = seawater. However, since they live IN the ocean....no regulation required!they live IN the ocean....no regulation required!

Osmoregulation StrategiesOsmoregulation Strategies

Elasmobranchs (sharks, skates, rays, chimeras)Elasmobranchs (sharks, skates, rays, chimeras)

– Maintain internal salt concentration ~ 1/3 seawater, Maintain internal salt concentration ~ 1/3 seawater, make up the rest of internal salts by retaining high make up the rest of internal salts by retaining high concentrations of concentrations of urea & trimethylamine oxide urea & trimethylamine oxide (TMAO). (TMAO).

– Bottom line…total internal osmotic concentration Bottom line…total internal osmotic concentration equal to seawater! equal to seawater!

– How is urea retained? How is urea retained? • Gill membrane has low permeabilityGill membrane has low permeability to urea so it is to urea so it is

retained within the fish. Because internal inorganic retained within the fish. Because internal inorganic and organic salt concentrations mimic that of their and organic salt concentrations mimic that of their environment, passive water influx or efflux is environment, passive water influx or efflux is minimized.minimized.

– ionic conc. approx 1/3 of seawaterionic conc. approx 1/3 of seawater– drink copiously to drink copiously to gaingain water water– Chloride cellsChloride cells eliminate Na eliminate Na++ and Cl and Cl-- – kidneys eliminate Mgkidneys eliminate Mg++++ and SO and SO44

==

advantages and disadvantages?advantages and disadvantages?

Osmotic regulation by marine teleosts...Osmotic regulation by marine teleosts...

Saltwater teleosts:Saltwater teleosts:

drinkdrink

active tran.active tran.

passive diff.passive diff.

NaNa++, Cl, Cl--

MgMg++++, SO, SO44==

HH22OO

NaNa++, Cl, Cl--

NaNa++, Cl, Cl--

chloride cellschloride cells

MgMg++++, SO, SO44==

kidneyskidneys

– Ionic conc. Approx 1/3 of seawaterIonic conc. Approx 1/3 of seawater– Don’t drinkDon’t drink– Chloride cellsChloride cells fewer, work in reverse fewer, work in reverse – Kidneys eliminate excess water; ion lossKidneys eliminate excess water; ion loss– Ammonia & bicarbonate ion exchange mechanismsAmmonia & bicarbonate ion exchange mechanisms

advantages and disadvantages?advantages and disadvantages?

Osmotic regulation by FW teleostsOsmotic regulation by FW teleosts

Freshwater teleosts:Freshwater teleosts: activeactive

passivepassive

HH22OO

NaNa++, Cl, Cl--

NaNa++, Cl, Cl--

don’tdon’tdrinkdrink

waterwater

kidneyskidneysIon exchangeIon exchange

pumps; beta chloride cellspumps; beta chloride cells

Thermoregulation in FishesThermoregulation in Fishes

Temperature is always an issue.Temperature is always an issue.

It affects metabolism, digestion, and reproductive behaviorIt affects metabolism, digestion, and reproductive behavior

Fish are conformers (well, sort of...)Fish are conformers (well, sort of...)

• Body temperature is that of the environment Body temperature is that of the environment ((poikilothermic ectothermypoikilothermic ectothermy))

• Each species has particular range of Each species has particular range of temperatures that they can temperatures that they can toleratetolerate and that and that are are optimaloptimal

• Big difference!Big difference!

Behavioral Thermoregulation in FishesBehavioral Thermoregulation in Fishes

• Although fish are Although fish are ectothermsectotherms, they can , they can alter their body temperature by moving to alter their body temperature by moving to habitats with optimal temperaturehabitats with optimal temperature

• Some fish can maintain body temperature Some fish can maintain body temperature greater than ambient - tunas, billfishes, greater than ambient - tunas, billfishes, relatives (nearly relatives (nearly endothermicendothermic))

Hot FishesHot Fishes

• Billfishes have warm brains – excess heat Billfishes have warm brains – excess heat production from muscles around eyeproduction from muscles around eye

Size matters...when you’re small!!!Size matters...when you’re small!!!Animals with high surface-to-volume ratios don’t hold heat.Animals with high surface-to-volume ratios don’t hold heat.

• ““Floyd, I am soooooooo tired, how long can this Floyd, I am soooooooo tired, how long can this go on?go on?

-Heavy Metal (80’s)-Heavy Metal (80’s)

• ““Life moves pretty fast, if you blink you just might Life moves pretty fast, if you blink you just might miss it.”miss it.”

--Ferris Buhler’s Day Off (90’s)Ferris Buhler’s Day Off (90’s)

Budding in coral allows multiple replications of the same entity.Since coral uses itself as a template, this is a form of asexual reproduction.

Rhizomes (runners) sent from sea grass is another Rhizomes (runners) sent from sea grass is another example of asexual reproduction.example of asexual reproduction.

Sexual reproduction: Union of two gametes.Sexual reproduction: Union of two gametes.

Reproductive strategies mayReproductive strategies mayinvolve mass production involve mass production of young…like this jawfish.of young…like this jawfish.

Advantage??? Advantage???

or single offspring with a high degree of parental care.or single offspring with a high degree of parental care.

Next time…real animals and real names.