Marine Life and Adaptations to the Marine Environment

Overview More than 250,000 identified marine

species Most live in sunlit surface seawater

Classification of living organisms

Three domains of Three domains of LifeLifeArchaea

Prokaryotic, includes “extremophile” bacteria

Bacteria Prokaryotic, includes

what used to be in Kingdom Monera

Eukarya Eukaryotic cells Includes Protists,

Fungi, Plants, and Animals

Domain Archaea Bacteria - Prokaryotic cells Cell wall differs from those bacteria in

Domain Bacteria Includes extremophile bacteria

○ Acidophiles○ Halophiles○ Thermophiles○ Etc.

○ These bacteria are found to chemosynthesize in hydrothermal vents

Domain Bacteria Bacteria – prokaryotic cells Cell wall made of peptidoglycan Includes Staphylococcus, Bacillus,

Vibrio, Pseudomonas, etc.○ Only a very small % of bacteria are

pathogenic○ Bacteria are very important in things like

nitrogen cycle, decomposition, food making, etc.

Cyanobacteria are photosynthetic bacteria

Archaea and Bacteria○ Most numerous organisms on Earth!!

- Think about how much bacteria lives just on you- Viruses are thought to out number bacteria but if

you are just talking about “live” organisms then bacteria are the most numerous

○ Simplest of organisms- But, can live in every thinkable habitat, even those

once thought to be unsuitable to life, very successful organisms!!

Now we will talk about Domain Eukarya○ Includes protists, fungi, plants, animals

Domain Eukarya Protists:

Algae○ Photosynthetic○ Can be unicellular, colonial, or multicellular

- Multicellular - “seaweed” – kelp, sargassum, sea lettuce- Unicellular – phytoplankton, produce majority of oxygen in

atmosphere comes from our phytoplankton, can cause red tides (examples are dinoflagellates and diatoms)

Protozoans○ Heterotrophic○ Unicellular○ Amoeba, paramecium

Domain Eukarya

FungiHeterotrophic

Secrete enzymes and absorb nutritionSince they are heterotrophic, they are more closely

related to animals than to plants

Multicellular (mold) or unicellular (yeast)

Domain Eukarya

PlantsAutotrophic, multicellularMany plant species cannot tolerate saltwater ○ Very few species grow in/near ocean

Sea grassesMangrovesDune plants

Domain Eukarya

AnimalsHeterotrophic, multicellular, have

motility at some point in life cycleWide variety○ From simplest of animals (sponges) to

most complex (mammals)

Viruses

Acellular entities○ Are they “alive”??? – many scientists say no○ Do not have the machinery for life

processes, have to take over host cell○ The ultimate “parasites”○ Viruses very prevalent in the marine

environment

Taxonomic classification Systemized classification of organisms Kingdom Phylum Class Order Family Genus Species

Fundamental unitPopulation of genetically similar, interbreeding

individuals

With new molecular methods (comparing DNA sequence and amino acid sequences of certain proteins), traditional taxonomy is changing○ Taxonomists are discovering new

relationships between species○ Molecular data gives a clearer picture of

relatedness as opposed to the traditional ways of classifying organisms:- Morphology, embryology, behavior, habitat, etc.

Let’s take a closer look at Plant and Animal taxonomy

Kingdom Plantae○ Nonvascular Plants – mosses, etc○ Vascular Plants

Seedless Vascular Plants – ferns, etcSeed Vascular Plants- Gymnosperms – “naked” seeds- Angiosperms – flowering plants (in the

marine environment these include mangroves, sea grasses, etc.)

Kingdom AnimaliaParazoa – no true embryonic tissues○ Sponges

Eumetazoa – true embryonic tissues○ 2 true tissues – radial symmetry; Cnidarians,

Ctenophores○ 3 embryonic tissues – bilateral symmetry; all

other animalsAcoelomate – only flatwormsCoelomates:- Protostomes- Deuterostomes

Radially Symmetrical Animals, 2 true embryonic tissuesCnidarians○ Class Anthozoa – sea anemones,

corals○ Hydrozoa – Hydra○ Scyphozoa – “jellies”

Ctenophores – no stinging cells, complete gut unlike in the Cnidarians

What are the embryonic tissue layers?Tissue layers that form during development○ Ectoderm○ Mesoderm○ Endoderm

What is radial symmetry? What is bilateral symmetry?

What is an acoelomate? What is a coelomate?

Bilaterally symmetrical animals are divided into 2 groupsProtostomes – 1st blastopore that forms

during development becomes the mouth○ Includes Annelids, Arthropods, Molluscs

Deuterostomes – 1st blastopore that forms during development becomes the anus○ Includes the Echinoderms, Chordates

Bilaterally symmetrical animalsPlatyhelminthes – flatwormsProtostomes○ Annelids○ Mollusks○ Nematods○ Arthropods

Deuterostomes○ Echinoderms○ Chordates

Platyhelminthes – flatwormsClass Turbellaria – free-living flatwormsClass Trematoda – flukesClass Cestoda - tapeworms

http://ocean.nationalgeographic.com/ocean/photos/marine-worms/#/marine-worms03-flatworm_18260_600x450.jpg

Protostomes Mullusca

Class Polyplacaphora - chitinsClass Gastropoda – snails, conchsClass Bivalvia – oysers, scallopsClass Cephalopoda – squid, octopus

Protostomes

AnnelidaClass Oligochaeta – earthwormsClass Polychaeta – many marine

species, sand worms, feather dustersClass Hirudinea - leeches

Marine feather duster worm

http://www.aquariumdomain.com/viewMarineInvertSpecies.php?invert_marine_id=26

Protostomes

Nematoda – round worms○ Many of these are parasitic

Protostomes Arthropoda

Largest group of animals on the planet!!!!Chelicerates – horseshoe crabs and arachnidsCrustaceans – marine and freshwater, crabs,

lobster, shrimp, barnaclesInsects and relatives

Limulus polyphemus Callinectes sapidus

Deuterostomes

EchinodermataAdults have pentahedral symmetry but

larvae are bilaterally symmetricalClass Ophiuroidea – brittle starsClass Echinodea – sea urchinsClass Holothuroidea – sea cucumberClass Crinodea – sea lillies

Sea cucumber from IRL

Deuterostomes Chordata

Characteristics: dorsal hollow nerve cord, notochord, post-anal tail, pharyngeal gill slits

Subphylum Urochordata – tunicatesLarvae have bilateral symmetry, look like tadpole

Subphylum Cephalochordata – lancelets Subphylum Vertebrata

○ Superclass Agnatha – jawless fishes○ Superclass Gnathostoma – jaws

Class ChondrichthyesClass OsteichthyesClass AmphibiaClass ReptiliaClass Mammalia

Vertebrates

Class ChondrichthyesSharks, rays

Vertebrates Class Osteichthyes

Bony fish, ray-finned fishGreat diversity in the ocean!○ Very small to very large○ Large tuna, grouper, sailfish○ Deep sea fish○ Flattened fish – flounder○ Seahorses○ Eels

Vertebrates

Class ReptiliaIncludes birds now!!!Sea turtles, sea snakes, pelicans,

penguins, osprey, sea gulls

http://seaturtlesofindia.org/?page_id=12

Vertebrates Class Mammalia

What are the characteristics of mammals?Carnivores: Sea otters, Polar bears, pinnepeds

(walruses, seals, sea lions)Sirenians: manateesCetacea○ Odontocetes – toothed whales: dolphins,

porpoises, sperm whale ○ Mysticetes: baleen whales: gray whale, right

whale, blue whale (largest animal to roam the Earth)

Classification in the marine environment by habitat and mobility PlanktonPlankton (floaters) NektonNekton (swimmers) BenthosBenthos (bottom dwellers)

Plankton

Most biomass on Earth consists of plankton PhytoplanktonPhytoplankton

Microscopic algae, Autotrophic ZooplanktonZooplankton

Heterotrophic Protozoans, tiny animals, larvae of larger

animals Bacterioplankton Bacterioplankton VirioplanktonVirioplankton

Viruses that infect bacteria and eukaryotic cellsViruses that infect bacteria and eukaryotic cells

http://i.ehow.com/images/GlobalPhoto/Articles/2110315/icephytoplankton-main_Full.jpg

Plankton o HoloplanktonHoloplankton

o Entire lives as planktono Example is algae, protozoans, small

microscopic animalso MeroplanktonMeroplankton

o Part of lives as planktono Juvenile or larval stages in the planktono Examples are lobsters, some fish species, etc.

o MacroplanktonMacroplanktono Large floaters such as jellyfish or Sargassum

o PicoplanktonPicoplanktono Very small floaters such as bacterioplankton

Nekton Independent

swimmers Most adult fish

and squid Marine reptiles Marine

mammals

Benthos

EpifaunaEpifauna live on surface of sea floor

InfaunaInfauna live buried in sediments

NektobenthosNektobenthos swim or crawl through water above seafloor

Most abundant in shallower water

Number of marine species More land species than marine species

Ocean relatively uniform conditions Therefore, less adaptation required, less speciation

Don’t get this fact confused with # of individual organisms

There are fewer different species in the ocean but greater # of individuals

Majority of life on Earth lives in the ocean!! Diversity in the ocean is high, also – think about different types of fish

(seahorses to sharks, for example)

Marine species overwhelmingly benthic rather than pelagic

○ Most of these will be in shallow coastal benthic areas where there is light and a lot of primary productivity

Marine organisms have a lot of adaptations for living in the marine environment

Let’s take a look at some of these adaptations

Adaptations of marine organisms Physical support

BuoyancyHow to resist sinkingDifferent support structures in cold

(fewer) rather than warm (more appendages) seawater

Smaller size

http://www.solaster-mb.org/mb/images

Adaptations to marine life

Oil in micro-organisms to increase buoyancy○ Over-time, if these

organisms die and sink to bottom

○ Can become offshore oil deposits

http://www.rpgroup.caltech.edu/~natsirt/aph162/webpages/dylanandco/lab1/image

Fish egg with oil droplet

Fig. 12.9

Adaptations to marine life Streamlining important for

larger organisms Less resistance to fluid

flow Flattened body Tapering back end –

fusiformfusiform

http://www.wissenschaft-online.de/sixcms/media.php/591

Fin designs in fish Vertical fins as stabilizers

○ dosral and anal fins

Paired fins for “steering” and balance○ Pelvic and pectoral

Tail fin (caudal) for thrust

http://www.biologycorner.com/resources/fish_fins.gif

Adaptations to marine life Narrow range temperature in oceans Smaller variations (daily, seasonally,

annually)Remember it takes longer to change water

temp than air temp Deep ocean nearly isothermal

Adaptations to marine life Cold- versus warm-water species

Smaller in cooler seawaterMore appendages in warmer seawater

Why?

Tropical organisms grow faster, live shorter, reproduce more often

Higher # of species in warmer seawaterNot necessarily higher # of individuals

More biomass in cooler seawater (upwelling)Polar waters are much more productive

(more plankton growth) than tropical waters

Adaptations to finding prey

Most fish cold-blooded but some are warm-bloodedHomeothermic-

body temperature above sea water temperature

Modifications in circulatory system

Mainly in fast-swimming fish

http://www.sciencedaily.com/images/2005/10/051031133653.jpg

Adaptations of deep-water nekton Mainly fish that consume detritus or each other Lack of abundant food Bioluminescence

○ http://www.ted.com/talks/edith_widder_glowing_life_in_an_underwater_world.html

Fishing lures Large, sensitive eyes

http://www.lifesci.ucsb.edu/~biolum/organism/pictures/myctophid1.jpg

Lanternfish

http://www.antoranz.net/CURIOSA/ZBIOR2/C0301

Anglerfish w/ males

Adaptations to marine life StenothermalStenothermal

Organisms withstand small variation in temperature

Typically live in open ocean EurythermalEurythermal

Organisms withstand large variation in temperature

Typically live in coastal waters

Adaptations to marine life StenohalineStenohaline

Organisms withstand only small variation in salinity

Typically live in open ocean EuryhalineEuryhaline

Organisms withstand large variation in salinity

Typically live in coastal waters, e.g., estuaries

Adaptations to marine life Extracting minerals from seawater High concentration to low concentration

DiffusionDiffusionCell membrane permeable to nutrients,

for exampleWaste passes from cell to ocean

Adaptations to marine life Osmotic pressureOsmotic pressure Less

concentrated to more concentrated solutions

IsotonicIsotonic HypertonicHypertonic HypotonicHypotonic

Adaptations to marine life Dissolved gases Some animals extract dissolved oxygen

(O2) from seawater through gills

Fig. 12.15

Adaptations to marine life Water’s transparency Many marine organisms see well Some marine organisms are nearly

transparent to avoid predation

Adaptations to marine life Camouflage through color patterns Countershading Disruptive coloring

http://www.youtube.com/watch?v=PmDTtkZlMwM

http://theplasticocean.blogspot.com/2012_07_01_archive.html

Adaptations to marine life Water pressure

Increases about 1 atmosphere (1 kg/cm2) with every 10 m (33 ft) deeper

Many marine organisms do not have inner air pockets

Collapsible rib cage (e.g., sperm whale)

Main divisions of the marine environment

PelagicPelagic (open sea)Neritic (< 200 m) and oceanic

BenthicBenthic (sea floor)Subneritic and suboceanic

Another classification scheme: EuphoticEuphotic DisphoticDisphotic AphoticAphotic

Pelagic environments – Open ocean

EpipelagicEpipelagic MesopelagicMesopelagic BathypelagicBathypelagic AbyssopelagiAbyssopelagi

cc

Fig. 12.19

Benthic environments – ocean floor SupralittoralSupralittoral

Transition from land to Transition from land to seafloorseafloor

Subneritic Subneritic (under (under

neritic)neritic)

Littoral Littoral (intertidal zone)(intertidal zone)

Sublittoral Sublittoral (shallow (shallow

tidal zone to 200m)tidal zone to 200m)

SuboceanicSuboceanicBathyal Bathyal (200-4,000m)(200-4,000m)

Abyssal Abyssal (4000-6000m)(4000-6000m)

Hadal Hadal (below 6000m)(below 6000m)

Fig. 12.19

Distribution of benthic organisms

More benthic productivity when closely beneath areas of high surface primary productivity Mainly on continental shelves Affected by surface ocean currents

Fig. 15.1

Humans and coral reefs Activities such as fishing,

tourist collecting, sediment influx due to shore development harm coral reefs

Sewage discharge and agricultural fertilizers increase nutrients in reef waters corals thrive at low nutrient levels Phytoplankton overwhelm at high

nutrient levels, limit light reaching the corals

Bioerosion of coral reef by algae-eating organisms

http://daac.gsfc.nasa.gov/oceancolor/images/coral_reef_algae.jpg

Coral covered with macroalgae

Ocean Literacy Principles 3.e - The ocean dominates the Earth’s carbon cycle. Half the primary productivity on Earth

takes place in the sunlit layers of the ocean and the ocean absorbs roughly half of all carbon dioxide added to the atmosphere.

5.a - Ocean life ranges in size from the smallest virus to the largest animal that has lived on Earth, the blue whale.

5.b - Most life in the ocean exists as microbes. Microbes are the most important primary producers in the ocean. Not only are they the most abundant life form in the ocean, they have extremely fast growth rates and life cycles.

5c. - Some major groups are found exclusively in the ocean. The diversity of major groups of organisms is much greater in the ocean than on land.

5.e - The ocean is three-dimensional, offering vast living space and diverse habitats from the surface through the water column to the seafloor. Most of the living space on Earth is in the ocean.

5.f - Ocean habitats are defined by environmental factors. Due to interactions of abiotic factors such as salinity, temperature, oxygen, pH, light, nutrients, pressure, substrate and circulation, ocean life is not evenly distributed temporally or spatially, i.e., it is “patchy”. Some regions of the ocean support more diverse and abundant life than anywhere on Earth, while much of the ocean is considered a desert.

5.g - There are deep ocean ecosystems that are independent of energy from sunlight and photosynthetic organisms. Hydrothermal vents, submarine hot springs, methane cold seeps, and whale falls rely only on chemical energy and chemosynthetic organisms to support life.

Sunshine State Standards SC.6.L.14.3 - Recognize and explore how cells of all organisms undergo

similar processes to maintain homeostasis, including extracting energy from food, getting rid of waste, and reproducing.

SC.7.L.17.3 - Describe and investigate various limiting factors in the local ecosystem and their impact on native populations, including food, shelter, water, space, disease, parasitism, predation, and nesting sites.

SC.912.L.15.5 - Explain the reasons for changes in how organisms are classified.

SC.912.L.15.6 - Discuss distinguishing characteristics of the domains and kingdoms of living organisms.

SC.912.L.17.2 - Explain the general distribution of life in aquatic systems as a function of chemistry, geography, light, depth, salinity, and temperature.

SC.912.L.17.7 - Characterize the biotic and abiotic components that define freshwater systems, marine systems and terrestrial systems.