Michelle Paddock Marine Biology Study Guide

what is osmosis?

diffusion of water across a semi-permeable membrane

why does osmosis create a challenge for marine organism?

because most marine organisms are osmoconformers, so cell salt content= external salinity

what is more common, osmoconformer or osmoregulator

osmoconformer

osmoconformer vs osmoregulator

osmoconformer: cannot control osmosis or its impacts

osmoregulator: can control salt content of cells & counteract osmosis

what types of organisms are osmoregulators?

certain plants, fish, reptiles and mammals

what are the methods osmoregulators use to regulate the balance of salt and water in their bodies

vascular plants vs algae

vascular plants- evolved special conductive tissues for transportation of water and food throughout the plant, drawing nutrients and water through the roots

algae- simpler than vascular plants, they have no conductive tissues for transportation. They are bathed in a water medium that contains minerals, so they have no roots

from an evolutionary perspective, what does the tree of life show?

‘ancient’/’lower’ animals are no better or worse adapted than ‘more complex’/ ‘higher’ animals

photosynthesis equation

CO2 + H20 + Sunlight → Sugars + O2

what else do photosynthetic organisms need for photosynthesis in order to grow, maintain themselves and reproduce?

what does it mean to be a plankton?

to be a wanderer

what are phytoplankton?

microscopic organisms that drift in the sunlit upper layer of marine and freshwater enviornments

what are the three main groups of phytoplankton?

cyanobacteria

diatoms

dinoflagellates

cyanobacteria

nitrogen fixers… is critical for life!!

diatoms

glass shells, many shapes, may have glass spikes and may link together

dinoflagellates

cellulose (opaque, brownish)

central groove for flagella (two flagella)

3 points vary in shape

what does it mean to have a larval stage?

it means that there is an indirect development, where the young look, act and eat differently than the adults

what is the pelagic zone?

open ocean

Buoyancy Adaptations: Portugues man-o-war and cyanobacteria

air pockets and air vaculoes

Buoyancy Adaptations: FIsh

air bladders,, swim bladder

Buoyancy Adaptations: Diatoms

lipids

Buoyancy Adaptations: sharks

lipids (livers)

Buoyancy Adaptations: squid

‘lighten’ body fluids (use less heavy ions)

what is an evolutionary adaptation

the process by which populations of organisms become better suited to their environment through natural selection

natural selection

the fundamental mechanism of evolution where organisms better adapted to their environment tend to survive, reproduce more and pass their favorable genetic traits to offspring

what are the three conditions necessary for natural selection to occur?

genetic variation

struggle for existence

differential survival and reproduction

genetic variation

arises via mutations in DNA

mutations are caused by…

• sexual reproduction- leading to greater genetic diversity COMPARED to asexual reproduction

struggle for existence

competition for resources or an environmental pressure

caused by variation in competitive success is due to genetic variation in traits. leading to…

differential survival and reproduction

natural selection leads to adaptations by…

inheriting traits that increase fitness (reproduction and survival)

natural selection can lead to evolution of species by…

genetic changes in a population over generations

phylum porifera (hole-y) Sponges

• cellular types multicellular with different types of cells

• no true tissues, a group of specialized cells that perform similar functions inside and outside the cell

• no symmetry, they are asymmetrical and show no true symmetry (sometimes misleading)

• UNIQUE cellular level of biological organization

what do sponges eat and how?

bacteria, plankton and DOM suspended in water. they are filter feeders

phylum cnidaria Cnidarians

• cellular & tissues multicellular with different types of cells & some colonial organisms

• diploblastic (develop from only two primary embryonic germ layers)

  • epidermis

  • gastrodermis

  • they also have a mesoglea instead of a mesoderm UNIQUE

• radial symmetry

• tissues level of organization

phylum cnidaria Cnidarians (body plan and nerve net)

• one opening surrounded by tentacles

  • tentacles possess specialized Cnidae

• decentralized nerves

• bidirectional flow in many cases

• sometimes contain rings

• actions reflex based

what do cnidarians eat and what structures help them eat?

plankton, crustaceans, small fish, other marine invertebrates

their specialized stinging cells located on their tentacles (cnidocytes and nematocysts)

what is alternation of generations? who does it?

specific cnidarians (jellies and hydroids) switch from being a sessile, asexual, polyp and free-swimming, sexual medusa each time they reproduce

how does alternation of life history allow cnidarians to be so successful (ie, abundant)

this allows cnidarians to thrive, combining the benefits of asexual and sexual reproduction within a single life.

asexual (rapid population growth and colonization)

sexual (dispersal and genetic variation)

What are the 4 classes within Phylum Cnidaria

class cubozoa

class scyphozoa

class hydrozoa

class anthozoa

class cuboza

box jellies

• do not look like a ‘true’ jellyfish but have distinct features

• shaped like a box, have box tentalces

class scyphozoa

true jellyfish

• large medusa

• oral arms

• thick mesoglea

class hydrozoa

portuguese man o’ war (uses a “sail” made up of small polyps)

• polyp types

  • gastrozoids

    • for feeding

  • gonozooids

    • for reproduction

• stem cells & regeneration

class anthozoa

sea anemones

• exist in polyp stage their entire life

• reproduce asexually by budding or binary fission

• reproduce sexually by releasing sperm into water which fertilizes eggs (strong currents and light limitation)

class anthozoa (what is the picture of)

stony corals

class anthozoa (what is the picture of)

soft corals

tropical water is often very clear- what does this show about resources in that water

it is nutrient-poor and low in organic productivity

what causes nutrient levels in tropical water to be so low

year-round solar heating creates limited vertical water circulation

symbiosis between corals and zooxanthellae

corals provide algae with protection and inorganic nutrients

zooxanthellae (dinoflagellates) photosynthesize, providing coral with food & extra energy

what makes it hard for corals to thrive in tropical waters?

there is a competition for resources (hard substrate, space, food), drives natural selection

also due to the lack of nutrients in the water itself

why are coral reefs such important ecosystems (for environment and people)

extremely high biodiversity, providing habitat & food for millions of organisms

they provide food, coastal protection and livelihoods

what is coral bleaching and why does it happen?

bleaching is the disruption of symbiosis with zooxanthellae

it happens because of HEAT STRESS

what two different processes cause most places on earth to experience 2 high tides and 2 low tides within each 24 hour period

gravitational force of the Moon

centrifugal force caused by the earth

what is a spring tide, when do they happen and why they cause the differences in tidal range on a monthly basis

period of maximum tidal range occurring twice a month

happen at a full moon and new moon

the moon’s orbit around earth is elliptical, creating variation in tide strength within a year

what is a neap tide and when do they happen

period of moderate, low-range tides occuring twice a month

happen at third quarter and first quarter moon

what creates rocky intertidal zonation patterns?

physical and biological factors that dictate where organisms can live creating distinct vertical layers

what are the four rocky interntidal zones

splash zone

upper intertidal zone

middle intertidal zone

lower intertidal zone

what is an indicator species of the splash zone

periwinkle snails

what is an indicator species of the upper intertidal zone

barnacles, limpets, algae

what is an indicator species of the middle intertidal zone

muscles

what is an indicator species of the lower intertidal zone

sea urchins, sea stars

3 different challenges for organisms in the rocky intertidal, an example of organisms and their adaptations that allow them to survive these challenges

uv exposure- anemones (create sunscreens)

drastic temperature changes- crabs (shells to deal with heat stress)

salinity variation & extremes- limpets (thick mucus rim around shell to block freshwater when clamped to rocks)

characteristics that define phylum mollusca

• muscular foot

• UNIQUE mantle

• UNIQUE radula

• visceral mass

• mantel cavity

• open circulatory system

phylum mollusca (body symmetry, structure and level of biological organization)

bilateral symmetric

organ-system level of organization

Body regions

1. head with paired eyes, sensory organs

2. soft body (visceral mass- contains organs) covered by mantle (thin tissue layer)

3. ventral muscular foot

Mantle

creates mantle cavity

• internal space- contains gills, anus

• may form siphon ( transfers liquid from a higher container to a lower one)

Radula

ribbon of teeth

• adaptations for grazing or predation

• limpets use radula to scrape microalgae from rocks

what type of nervous system do phylum mollusca have?

series of clusters rather than 1 brain

how does phylum mollusca reproduce?

broadcast spawn (external fertilization)

some (octopus, some snails) do internal fertilization

what type of larvae do phlyum mollusca have?

trophic larvae in some…

in some gastropods and bivalves: trocophore develops into veliger larva

4 classes within phylum mollusca

class gastropods “stomach-foot”

class polyplacophora (chitons)

class bivalvia (clams, mussels, oysters)

class cephalopoda

class gastropods… including example (feeding and reproduction)

SNAILS!!

shell anatomy: operculum

feeding diversity:

1. herbivores (scrape microalgae from rocks)

2. deposit/detritus feeders (mud snails)

3. predators (cones)

reproduction

• most separate sex, some hermaphrodites

• if internally fertilize, males have long, flexible penis

• fertilized eggs laid in strands

class polyplacophora example and body plan

chitons

Body plan

• 8 exposed plate-like shells

• internal organs NOT coiled

• many paired gills in mantle cavity

• cilia create respiratory currents

class polyplacophora feeding and reproduction

Feeding

• herbivores of microalgae on rocks

Reproduction

• separate sexes

• broadcast spawm

• external fertilization

• trophore larvae

class bivalvia… including example and body plan (shell)

clams, mussels, oysters

Body plan

• laterally compressed

• shell: 2 valves

• valves hinged at umbo (oldest part)

• grow from umbo in annual rings

• hinge ligament- keeps shell open

• adductor muscle- keeps shell closed

• hinge teeth- keep shells in place

class bivalvia body plan (soft body)

• mantle lines inner side of both shells

• entire body in mantle cavity

• a mouth but no head, no radula

how do bivalves eat?

filter feeders

• plankton captured in gills

• gills have mucus strands and cillia

• palps- aggregate food, move to mouth (no radula)

• enzyme- secreting rod in stomach, rotates

class bivalvia lifestyle variation

1. burrorwers- some clams- enlarged foot for burrowing

2. boring bivalves

3. sessile

4. free-living

class cephalopoda “head-foot” and ex. and basic body form

cuttlefish, octopus, squid, chambered nautilus

shell/structural support

describe at least 2 different reasons why soft sediment ecosystems can be challenging for organisms

Mobile substrate

wave & tide impact

what is bilateral symmetry

when an organism can be divided into identical mirror-image halves

why is bilateral symmetry such an important evolutionary advancement?

it allows for cephalization, have a head & central nervous system

phylum platyhelminthes: flatworms

dorsoventrally compressed

central nervous system- chemoreceptors in head

three tissue layers & no body cavity

guy with single opening (2-way)

what are three tissue layers of flatworm?

a) Epidermis

b) muscles

c) mesoderm

flatworm feeding

pharynx= musculat tube, projects from mouth swallow prey whole (some)

on some predators & parasites: stylet on penis

flatworm repreoduction

sexual & asexual reproduction

no larval stage

penis fencing!

what are the ecological roles of flatworms?

meiofauna

important predators

mutual & commensal symbionts

parasites regulate host populations

meiofuna

funnel nutrients to larger organisms

Phylum Nemertea (ribbon worms)

unsegmented

circulatory system-blood

complete digestive tract (mouth & anus)

predators and scavengers

UNIQUE proboscis

phylum annelida (segmented worms)

trocophore larvae

burrowers (predators)

tube-dwellers (filter feeders)

symbiotic

polychaete worm with cetae and parapodia

what is the function of cetae

traction or grip

burrowing

sensory perception

what is the function of parapodia

locomotion

respiration

feeding defense

what is an estuary?

partly enclosed area where freshwater & seawater mix (brackish water) due to tides

three physical features that structure estuaries

close interaction between land and sea

challenging environment: extreme fluctuations

salinity fluctuates greatly daily and seasonally

how do estuarine organisms reduce physical stressors and what problem does this create?

burrow, creates a problem of oxygen

why are estuaries, marshes and wetlands ecologically important?

highly productive

feeding & breeding area

coastal protection

export of detritus

70-90% USA east coast commercial catch is estuarine dependent

phylum arthropoda characteristics

bilateral symmetry

organ system level of biological organization

UNIQUE segmented, flexible body… composed of head, thorax and abdomen

UNIQUE most segements with jointed appendages moved by muscles

UNIQUE tough, non-living (chitin) exoskeleton

what adaptation allows arthropods to be so successful on earth?

waterproof exoskeleton, jointed appendages, segmented body plan and highly efficient respiratory system

what is molting?

where an animal sheds its old, warn-out coverings to make way for new growth

why is molting needed by arthropods?

they need it to grow

phylum echinodermata characteristics

*pentamerous radial symmetry (adults) bilateral symmetry (larvae)

organ system level

endoskeleton

covered in thin layer of ciliated tissue, often with spines/bumps

*water vascular system

*tube feet

generation ability

separate sexed

breeding by broadcast spawning

locomotion