AICE Marine biology 4.1-4.3

Binomial nonmenclature

Universally recognized two-word name for a particular species

Genus

First part of binomial nonmenclature given the capital letter

Species

Second part of binomial nonmenclature given the lowercase letter

Levels of classification

• Domain — different kingdoms

• Kingdom — different phylum

• Phylum — different classes

• Class — similar orders

• Order — similar families

• Family — one of more similar genus

• Genus — one of more closely related species

• Species — unique to each organism within a genus

Dichotomous key

• System used to identify organisms

• Made up of pairs of contrasting descriptions

What are the 8 groups of marine organisms

• Phytoplankton

• Zooplankton

• Echinoderms

• Crustaceans

• Bony fish

• Cartilaginous fish

• Macroalgae

• Marine grasses

Plankton

Diverse collection of microscopic organisms that have limited mobility and drift in water currents

Why are plankton considered keystone species

They are indicative of the health of an ecosystem

Two groups plankton is divided in to

Phytoplankton (producers) and zooplankton (consumers)

Main types of phytoplankton

Diatoms and dinoflaggellates

Diatoms

• Unicellular

• Cell walls with silica

• Found in surface waters, reproduce rapidly

• Represent base of food web

• Consumed by krill

Dinoflagellates

• Unicellular

• No silica cell walls

• Found in surface water, reproduce rapidly

• Some produce toxins that can poison fish and accumulate in shellfish poisoning humans and other organisms

Zooplankton

• Consumers (including larvae, copepods, jellyfish)

• Migrate vertically in the water column each day to feed on phytoplankton

• Sensitive to environmental changes (pullution, microplastics, acidification, etc)

Larvae

Planktonic stage of fish and invertebrates like sea star (adapted to life floating in the ocean)

Copepods

• Most abundant and diverse group of zooplankton

• Are crustaceans, herbivores,, feed on diatoms

• Bodies are divided (head, thorax, abdomen, two antennae, 2-4 pairs of appendices extend thorax)

• Exoskelton made of calcium carbonate and have spikes for protection and better floatation

Jellyfish

• Found in every part of the ocean, belong to cnidaria group

• Body with two parts: medusa (transparent bell) and tentacles with stinging cells

Krill

• Shrimp like organisms

• Feed on zooplankton and phytoplankton

• Important source of food for birds, fish, seals, whales

Echinoderms

• Phylum including invertebrates like sea-stars, sea urchins, sea cucumbers, sea lilies and brittle stars

• Body has thin layer of skin over a hard calcium carbonate skelton

• Have planktonic larvae

• Have pentaradial symmetry (five arms radiating around a central body cavity)

• Movement through a system of eater filled tubes whuch increase of decrease the water pressure in tube feet

Main uses of tube feet

• Open shells of oysters and clams

• Act as suction cups to help adhere to the seafloor

• Help in gaseous exchange for respiration (takes in O2 and releases CO2)

Ecological importance of Crown-of -thorns starfish

• Support colonization of slow growing coral

• Increase biodiversity of the reef

Ecological importance of sea urchins

• If sea urchins are overharvested → increase in kelp population

• If sea otters are removed or decline → Sea urchins population increase → decrease of kelp population → unbalance

Ecological importance of sea cucumbers

• Borrow in sand and provide oxygen to other organisms living there

• Produce nitrogenous waste → important nutrient

Economic importance of echnioderms

• Sea cucumbers and sea urchins can be a source of income (using in agriculture, fishing, food delicacy in Chinese cuisine, medicine to treat fatigue, constipation, frequent urination)

• COTS can damage the ecotourism industry if destroy the coral reefs

Crustaceans

• Can be found in salt, brackish, freshwater

• Including crabs, crayfish, lobsters, krill, shrimp, prawns, barnacles, copepods, etc

• Have hard exoskeleton made of calcium and chitin

• Outside of exoskeleton offers protection against predators and water loss

• Inner part of exoskeleton to support the attachment muscles

Ecological importance of Crustaceans

• Detrivores, break down the organic matter → help recycle the mineral nutrients

• Krill is a target for commerical fishing, overfishing krill can lead to decline in population of them and then phytoplankton bloom → harmful toxins

Economic importance of Crusteceans

• Large crustaceans = food for us

• Small crustaceans = food for the larger crustacean

• Krill is eaten in certain countries like Japan

• Used as bait in aquariums, aquaculture, fishing, pharmaceutical industry

Bony fish external and internal features

• Lateral line

• Operculum

• Gills

• Swim bladder

• Scale

• Bony skeleton

Lateral line

• Extremely visible

• Contains sense organs that can detect changes in electric field as well as vibrations in water

• Assists in shoaling behavior, navigation, finding prey

Operculum

• Bony flap covering and protecting the gills

Gills

• Supported by bony gills arches

• Used for gas exchange

Swim bladder

Buoyancy organ

Scale

• Made of bone, overlapping, flexible

• Covered by skin and mucus

• Used for protection, drag reduction

Ecological importance of bony fish (5)

• Excretion → nutrients (nitrates and phosphates) used by producers

• Link aquatic and terrestrial ecosystems

• Example: salmon to trees

Economic importance of bony fish (10)

• Important source of protein and 5 amino acids we cant synthesize

• Cod liver: rich in iodin, vitamin A and D

• Scales: jewelry

Cartilaginous fish features (11)

• Skelton and jaws made of cartilage only (less calcium, softer, more flexible than bone)

• Spiracle

• Denticles

• Dorsal fin

• Not extremely visible lateral line (under the skin)

• Caudal fin (heteroceral)

• Anal fin

• Pelvic fin

• Pectoral fin

• 5-7 pairs of gil slits

• No swim bladder (must keep swimming to keep buoyant)

Ecological importance of cartilaginous fish

• Sharks play ecological role in marine food webs: keep prey population in check= keystone species

• Sharks also control the population of invasive species (lionfish)

Economic importance of cartilaginous fish (6)

• Fins are a culinary delicacy in China

• Shark liver oil is a source of vitamin A, used in preserving leather and wood, in cosmetics for treating arthritis and cancer

• Denticles: used in Japan to cover sword hilts

• Shark leather: boots, belts, wallets

• In Greenland Inuits make rope from shark skin

• Ecotourism: diving with sharks and rays bring important revenue

What phylum to bony and cartilaginous fish belong to

Phylum Chordata

Chordates common features

• Notochord

• Dorsal neural tube

• Pharyngeal slits

• Post anal tail

Notochord

Flexible, rod-shaped organ, extends the length of the body and allows body to bend during muscle contractions

Dorsal neural tube

Tube-shaped organ, extends the length of the body

During development anterior part becomes the brain and posterior part becomes the spinal cord

Pharyngeal slits

Links mouth cavity and digestive system

In bony and cartilaginous fish it develops into gill arches to support ventilation across the gills

Post anal tail

Located at the rear of the fish, used for swimming

Macroalgae

• Large marine producers, photoautotrophs, found in shallow areas

• Examples: kelp and seaweed

• Body is called a thallus

Macroalgae features

• Holdfast

• Stipe

• Blades

• Gas bladders

Holdfast

• Strong, root like structure

• Anchor the kelp to the seabed (no function in absorbing minerals)

Stipe

• Long, tough vertical stalk

• Connects to holdfast to the blades

Blades

Leaflike structure, absorb light and minerals

Gas bladders

• Found underneath the blades

• Act as floatation acid and contain accessory pigments to absorb traditional wavelengths of light

Ecological importance of macroalgae (2)

• Kelp forests serve as habitat for a diverse range of fauna

• Generates large quantities of nutrients/detritus

Economic importance of macroalgae

• Cooking: wrapping suishi rolls, sea weed is rich in vitamins and minerals and low in fat

• Food industry: used as additive in many foods

• Cosmetics and herbal medicine: skin creams, herbal remedies, etc

Marine plants/sea grasses

• Are flowering plants

• Have rots and rhizome (thick, horizontal) in seabed

• Leaf structure — epidermis layer with chloroplast, no stomata, and very thin waxy cuticle

• Plants can reproduce sexually and asexually

Marine plants ecological and economical importance

• Base of food webs

• Provides food, nutrients, detritus, habitat

• Nursery ground for marine invertebrates

• Sustain biodiversity → ecotourism, recreational fishing, snorkeling

Types of biodiversity

• Species diversity

• Genetic diversity

• Ecological diversity

Species diversity

• Measure of abundance and richness of a species in each place at one time

• Species abundance = number of individuals per species

• Species richness = number of species in an area

Genetic diversity

• The variety of forms of gene’s alleles within a species

• Measure of allele frequency/gene (less alleles = population less able to adapt to changes in environment

Ecological diveristy

• Variation of ecosystems/habitats on a regional or global level at one time

• Hard to measure since ecosystems merge into the ecosystems around them

Unstable and extreme environments with low biodiversity

• Hydrothermal vents — extreme conditions because the abiotic conditions are out of zone of tolerance (like temp, pH, pressure, toxins) not a lot of organisms live here = low biodiversity

• Reef slopes — steep walls/slope at the front of reef, sandy substrate constantly changing due to exposure to wave currents, wind erosion

Stable, non extreme environments with high biodiversity

• Coral reefs — abiotic conditions close to optimum for producers → long food chains

• Rocky shores — good substrate for attachment, protective habitats (rock pools, crevices) → great biodiversity

Benefits of marine biodiversity (4)

• Protection of the physical environment (coral reefs protect coastlines)

• Climate control (phytoplankton absorb CO2 and release O2)

• Providing food resources (algae, crustaceans, and fish)

• Sources of medicine (anticancer drugs such as keyhole limpet hemocyanin (KLH))