Chapter 13-15 - Life in the Ocean, Primary Productivity, Invertebrates and Vertebrates

Evolution

the maintenance of life under changing conditions by continuous adaptation of successive generations

What is evolution based on?

Natural selection

Natural selection

a mechanism of evolution. organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success. this process causes species to change and diverge over time

What does physical isolation do to a species?

• Evolutionary change becomes rapid due to the small number of breeding animals in the area

• Favorable traits accumulate quickly within a species

• New species arise—see speciation

What are Charles Darwin’s main points about natural selection?

1. More offspring is produced than can survive

2. All organisms have random trait variations that can be passed down to offspring

3. Some traits are favorable—help organisms survive better

4. Organisms with favorable traits are more likely to survive and reproduce

5. The environment influences traits that contribute to an organism’s, and their offspring’s, success

What is mutation?

a spontaneous or induced change in an organism’s DNA, most of which are unfavorable. some are inheritable

How are mutations different from natural selection?

Organisms with mutations are usually eliminated or abandoned.

Adaptation

an inheritable structural or behavioral modification

Speciation

the formation of a new species, which arise by physical isolation (which causes rapid evolutionary changes)

Mass extinction

an event where multiple species die off simultaneously

What are some causes of mass extinction?

• Widespread volcanism

• Asteroid impacts

• Climate changes

• Rapid changes in geography and ocean currents

• Humans

What are the three domains of organisms?

1. Domain Bacteria - small, single celled organisms. evolved diverse metabolic abilities (photosynthetic and heterotrophic)

2. Domain Archaea - very small, single celled organisms. known as extremophiles, due to their ability to withstand extremely hot or corrosive environments

3. Domain Eukarya - each cell has a nucleus. multicellular. consists of fungi, protists, plants and animals. shares a lot of biochemical characteristics with Archaea

Convergent evolution

when organisms that aren't closely related evolve similar features or behaviors, often as solutions to the same problems

What are the four major elements of living organisms?

1. Carbon

2. Hydrogen

3. Nitrogen

4. Oxygen

Viscosity

a fluid’s resistance to flow. affected by temperature

Drag

the resistance to movement of the organism due to the fluid it swims through

How does viscosity and drag affect organisms?

• Mobility is hindered

• Smaller organisms are more affected than larger ones

• Most organisms experience gradual sinking

• Organisms will increase their surface area and friction by having body extensions, plumes, hairs, ribbons and spines to offset sinking

• Warm water species tend to have more protruding structures because the water is (thinner) and they sink faster

How do larger animals struggle with viscosity?

• They suffer from the chaotic flow of water as they pass through it; this is called turbulence

• Animals are slowed, but have adaptations to help survive

  • A narrow body shape to help maneuver through water better

  • Secreting mucus or oil so water doesn’t stick

  • Tucking fins into grooves in the body

  • Skins with indentations to help break up surface eddies

Plankton

a collection of organisms that drift in water (or air) but are unable to actively propel themselves against currents (or wind)

Why are plankton unable to propel themselves against currents/wind?

They’re too small and too lightweight

Planktons are autotrophic, which means what?

They typically make their own food through photosynthesis. Their productivity depends largely on light and nutrient availability

Microbial loop

a trophic pathway where, in aquatic systems, dissolved organic carbon is returned to higher trophic levels via its incorporation into bacterial biomass

Zooplankton

the heterotrophic component of the planktonic community, having to consume other organisms to thrive. most numerous primary consumers in the ocean. not all are small, some are macroscopic (bigger than 1cm)

What do zooplankton consume?

species (diatoms, dinoflagellates, coccolithophores), forming a food web that eventually supports larger animals like fish

Phytoplankton

the single celled, autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. responsible for 90-98% of the ocean’s primary productivity.

Phytoplankton vs. Zooplankton

• Phytoplankton: self-feeding (autotrophic) plankton. lives in well-lit layers of water to conduct photosynthesis

• Zooplankton: heterotrophic plankton. feeds on other plankton to survive

Dinoflagellates

a monophyletic group of single-celled, autotrophic eukaryotes. usually considered protists. they’re mostly marine plankton, but they are also common in freshwater habitats. some are bioluminescent

Diatoms

any member of a large group comprising several genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. some are round, elongated, branched or triangular. reproduces asexually. more than 55% of sunlight absorbed by it is converted into useful energy

Coccolithopores

single celled organisms which are apart of the phytoplankton community. extremely small (measured in nano units). covered in disks of calcium carbonate. it often lives in the photic zone, and is a major contributor to phytoplankton productivity

Cyanobacteria

a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. able to absorb blue light in the deep euphotic zone. extremely small (0.2-2 micrometers)

Seaweed

grass found in bodies of water. non-vascular, plant like structures, classified as protists. multicellular algae further classified into 3 major groups based on colour. contribute 2-10% of ocean's productivity

Chlorophyta

the green algae. most groups of these are unicellular

e.g. Ulva—lettuce-like edible plant

Phaeophyta

the brown algae. multicellular.

e.g. kelp, rockweed

Rhododphyta

the red algae. makes up one of the oldest groups of eukaryotic algae

e.g. Irish moss, dulse

Seagrass

neither grasses nor seaweeds; these are flowering vascular plants that grow in marine environments

Mangrove

tangled mass of trees. their roots provide anchorage, trap sediments, protect small organisms

What factors limit productivity in the ocean?

• Autotrophs need water, CO2, inorganic nutrients, and sunlight

  • Water and CO2 are not limiting factors since they are abundantly available 

Nutrients and sunlight are the limiting factors

What are invertebrates?

animals that are ‘lacking a backbone.’ more than 90% of all living and fossils animals are invertebrates. they are generally soft-bodied and lack an internal rigid system, but many have a hard protective outer covering, like a shell.

What do Platyhelminthes, Nematoda and Annelida all have in common?

Animals in this phylum are worms

Porifera

sponges. widely distributed from intertidal zone to the abyss. ‘primitive’ true animals. they’re found at all latitudes, and can range from the size of a bean to a small automobile.

How do sponges feed?

Suspension feeders (also known as filter feeders) strain the plankton from the surrounding water. They don’t have digestive systems, but individual digestive cells.

How are sponges’ bodies maintained?

• Spongin fibres

• Spicules

Cnidaria

A phylum that consists of jellyfish, sea anemones and coral.

• About 9,000 marine species

• Carnivorous; feeds on zooplankton and small fish

• Uses stinging cells (cnidoblasts) on tentacles to entangle prey, immobilizing them with toxins

What is Cnidaria’s body structure like?

They’re made of two layers of cells:

• Gastrodermis (inner layer)—digestion and reproduction

• Epidermis (outer layer)—capturing prey and protection

They have radial symmetry and have 2 different forms: polyp and medusa

Platyhelminthes

This phylum consists of flatworms. They are carnivorous; some are parasitic but most are free-living. Free-living flatworms are often found on the underside of intertidal rocks.

What is a flatworm’s body structure?

They have bilateral symmetry and are the most primitive organisms with a central nervous system.

Nematoda

This phylum consists of roundworms. They were the first to have a flow-through digestive tract. They are parasitic, often found in fish like herrings, red snappers, salmon, halibut and some bass

Annelida

This phylum consists of ringworms. Their class is polychaeta meaning many bristles—they are one of the most important marine animals. Some burrow in sediments while others make calcareous tubes

What are some characteristics of a ringworm’s body?

• First to have a segmented body

• 1-15cm long

Mollusca

This phylum consists of about 80,000 (known) species, which includes clams, snails, octopi, and squids. Few have acute sight and considerable intelligence

What are some characteristics of a mollusc’s body structure?

• Most have an internal or external shell

• Bilaterally symmetrical

• Generally well-developed heads and nervous systems

• Flow-through digestive system

Classes of Mollusca

• Polyplacophora: chitons

• Gastropoda: snails

• Bivalia: clams, oysters and mussels

• Cephalopoda: octopus and squid

Arthropoda

This phylum includes the class of crustaceans: lobsters, shrimps, crabs, copepods and barnacles. They come in large numbers with a variety of habitats, and consume large quantities of food

What is an arthropoda’s body structure like?

• Segmented body with jointed appendages

• Has an exoskeleton

• Bilateral symmetry

Barnacle

• First a larva that swims around in water, then settles on a rock headfirst

• Sticks a foot out of the top of its shell and uses it as a rake to pull plankton into its mouth

• When the tide is low, their roof is closed in order to conserve water

• Really freaky sex life

Echinodermata

A phylum that consists of starfish, sea urchins and sand dollars.

What is an Echinodermata’s body structure like?

• Unique water vascular system used for locomotion and feeding

• Internal skeleton, spiny skin

• Adults: radially symmetrical

• Larvae: bilaterally symmetrical

• Starfish have tube feet that can suction onto shells in order to feed

Chordata (invertebrates)

an advanced phylum of invertebrates, the third-largest phylum of the animal kingdom. consists of Tunicates, Amphioxus. They have a notochord, a stiffening back cord, a tubular dorsal nervous system, and gill slits at some point of development

• About 5% lose their notochord into adulthood (invertebrates)

• About 95% retain their notochord

Tunicates (sea squirts)

• Suspension feeders

• Name originates from strong outer coat, “tunica”

• Resemble sponges, can be loners or in groups

• Problematic for PEI aquaculture

Amphioxus

• Small, clear fish-like animal

• Hides in sediments.

• This animal is a transition between invertebrates & vertebrates

• Sharp at both ends

Taxonomy

biological classification. the science of classifying living things into categories based on their characteristics and/or behaviour

Linnaeus

classification system. hierarchy. each level is included in the level above it; levels get increasingly specific from kingdom to species

Modern Domain Classification

Archaea, Bacteria, Eukarya

The 8 taxa (levels) of animals

• Domain

• Kingdom

• Phylum

• Class

• Order

• Family

• Genus

• Species

The eight level system memory tool (whatever)

Domain, King Philip Came Over For Good Spaghetti

Binomial Nomenclature

the system used by scientists to name living things. developed by Carl Linnaeus

What are some general rules for Binomial Nomenclature?

• Latin or Greek is a universal language for science

• Each living thing has two names

  • Ex: Human (common name)

  • Homo sapiens (scientific name)

• First letter in Genus is always capitalized. Genus name is always lower case

What is the blue mussel’s scientific name?

Mytilus edulis

What is a mediterranean mussel’s scientific name?

Mytilus galloprovincialis

What is a Californian mussel’s scientific name?

Mytilus californianus

Chordata (vertebrates)

a phylum of vertebrates. consists of fish, reptiles, birds, mammals, etc. possesses a notochord at some time in their life cycle. possesses gill slits at some point in their life

Vertebrate Animals

• Belong to Phylum Chordata and Sub-phylum Vertebrata

• Commonly referred to as vertebrates (animals with a backbone)

• The notochord has been replaced by the vertebral column

• The vertebral column (i.e. Spine, backbone) is a structure that surrounds and supports the spinal cord (the main nerve that runs down the back)

• The nerve cord is hollow and is dorsally located (found along the back surface)

Agnatha (jawless fish)

consists of lampreys and hagfish. both have snake-like bodies, sucker-like mouths, and a flattened tail that provides forward motion

Hagfish

ocean scavengers, not much is known about them. emits a slimy mucus in order to protect its body and move more efficiently in the ocean

Lamprey

fresh and saltwater fish, parasitic, preys on other fish. sometimes inaccurately called eels

Chondrichthyes (cartilaginous fish)

a class of jawed fish with cartilage skeletons (NOT bones). consists of sharks, rays, and skates. they don’t have gill covers, and have to keep moving in order to breathe. they have different kinds of scales that look and feel like sandpaper

Osteichthyes (bony fish)

a class of fish that have skeletons made of bone (NOT cartilage). they have scales, jaws, paired fins, a swim bladder, gills and fill cover. they are ray-finned and lobe-finned

What are some problems fish face in water?

Water is more difficult to move through than air, so fish will feel a force working against them when trying to swim

What are some adaptations fish have maintained in order to move through water?

1. Some secrete a mucus/slime to reduce friction and to be more slippery

2. A hinged tail for propulsion and an inflexible main body works to reduce drag

3. Eels that have an ‘S’ shape is only okay because they are so thin; otherwise, it is not very efficient

4. Fish keep from sinking by either

   1. swimming continuously

   2. using their swim bladder (filled with gas) to maintain their position in the water column

5. Gas exchange; O₂ diffuses into the gills as water passes over and CO₂ diffuses from blood → water

Amphibia

a class of moist four-limbed vertebrate animals. consists of frogs, toads and salamanders. they spend time on both land and water; none are exclusively marine. their smooth, moist skin is in constant need of water. their eggs don’t have shells as their larvae are aquatic

Reptilia

a class of scaly four-legged vertebrates. there are a variety of different reptiles in different habitats; some thrive in the ocean while others thrive in drier areas. sea turtles are the most successful marine reptile, as they are good with navigation

Aves

a class of sea birds. they have feathers to insulate their bodies. they are homeotherms (warm-blooded). their bones are light, thin and hollow to allow for flight. they have beaks instead of teeth, and are voracious feeders

Mammalia

a class of mammals, which is the most advanced group of vertebrates (animals with backbones). homeothermic (able to maintain its body temperature), give birth to live young and have hair at some point in their lives. three classes: Cetacea, Carnivora, and Sirenia

What 4 characteristics does the class Mammalia have?

1. Streamlined bodies with adapted limbs for swimming

2. Generate a high internal temperature with a high metabolic rate and maintain this heat with thick layers of insulating fat and fur

3. A highly modified respiratory system to collect and hold large amounts of oxygen

4. Osmotic adaptations to avoid the need for finding freshwater

Cetacea

a class of marine vertebrates. mammals. consists of porpoises, dolphins, and whales. they have paddle-shaped forelimbs for steering and thick, oily blubber for insulation, buoyancy, and energy storage. whales are divided into 2 suborders: Odontoceti and Mysticeti

Odontoceti

toothed whales, active predators, use echolocation, intelligent, offensive sound to stun prey

Mysticeti

baleen whales, no teeth, filter feeders (swallowing large amounts of shrimp like zooplankton or small fish)

Carnivora

a class of mammals that eat meat. consists of seals, sea lions, walruses, and sea otters. they leave the ocean for varying period of time to mate and raise the young. they’re known for their graceful swimming, and pursue small fish

Sirenia

a class of vertebrates commonly referred to as “sea cows.” consists of manatees and dugongs. herbivores. they are bulky, lethargic, and are generally small-brained. they were first compared to mermaids by early Greeks