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Chapter 6 and 7 Marine biology Michael Slemp. Polar bear Ursus Maritimus Native largely within the...

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Chapter 6 and 7 Marine biology Michael Slemp
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Chapter 6 and 7Marine biologyMichael Slemp

Polar bearUrsus Maritimus

Native largely within the Arctic circle Largest land carnivore (eats meat) Largest bear (together with Kodiak bear) Born on land, spend most of their time at sea The polar bear has an extremely well developed sense of smell,

being able to detect seals nearly 1 mile away and buried under 3 feet of snow

Superbly insulated by up to 4 inches of blubber The white coat usually yellows with age The polar bear is an excellent swimmer and individuals have been

seen in open Arctic waters as far as 200 mi from land With its body fat providing buoyancy, it swims in a dog paddle

fashion using its large forepaws for propulsion

The Water Planet What percentage of the earth surface is covered by

water? 71% of earths surface is covered by water. Can all the earth’s water be used for drinking? The majority of the water that covers the earth is

salt water and can not be used for drinking. Where does most of the drinking water come from? Most of the water that we rely on comes from

underground aquifers and rivers Because drinking water is essential for life, wars and

disputes have occurred over drinking water.

The Water Planet The average depth

of the ocean is 12,238 feet

Challenger Deep in the Mariana Trench is the deepest in the ocean (35, 558 feet)

Mt Everest could fit in the trench and still be 6,527 feet from the surface from the top of the mountain

Water molecule H2OO = Oxygen (one)

H = Hydrogen (two)

Covalent bond between O and H

(covalent = sharing)

Unequal sharing

causing water molecule to be

polar molecule. This

results in positive and

negative ends.

O = negative region (minus)

H = positive region (plus)

Review - Water molecule H2O

What does “O” stand for?

What does “H” stand for?

What is the name of the bond

between “O” and “H” ?

What type of molecule is

water?

What region is around “O” ?

What region is around “H” ?

Oxygen

Hydrogen

CovalentWhat does

covalent mean?

Sharing

What causes polar

molecule?

Polar molecule

Unequal sharingWhat is the result of unequal

sharing?Positive and

negative regions

Negative (minus)

Positive (plus)

Water = many H2O molecules

Oxygen is a region with

negative chargeHydrogen is

a region with

positive charge

Opposite charges attracts resulting in creation of a bond

between oxygen of one water molecule and hydrogen of another

water molecule

This bond is called

HYDROGEN BOND

HYDROGEN BOND

Hydrogen bond:

• Weak covalent bond• Easily breaks and reforms• Cumulative strength in

numbers• Causes water to be a

liquid at room temperature (without hydrogen bonds it would be gas)

• Makes water more viscous (viscosity = tendency for fluid to resist a flow)

HYDROGEN BOND

Hydrogen bond:

• Causes surface tension (forms skin-like surface)

• Imagine water strider that walks on the top of the water

• Surface tension also affects how quickly the ocean takes up atmospheric CO2 and releases O into the air

• Think of air pollution in relationship with ocean?

HYDROGEN BOND

Hydrogen bond:

• Causes water cohesion • It means that water

molecules stick together which allows for a more organized structure

• Causes water adhesion• It means that water

molecules stick to other materials

Cohesion = water molecules stick together• Water sticks together• Water flows• Water creates rain drops

Adhesion = water molecules stick to other materials• Water sticks to a knife• Water sticks to spider web• Water sticks to leaves

HYDROGEN BOND

Hydrogen bond:

• When liquid water changes to ice, hydrogen bonds cause unique phenomenon.

• As ice forms, hydrogen bonds cause water molecule to spread apart and rearrange into crystal structure

• This makes ice less dense than liquid water

• This property of water explains why ice floats in water and also why there is volume expansion when liquid water becomes ice

• Floating ice forms a layer that insulates the water below.

• This causes the water below to retain heat and remain liquid.

• Ultimately this water property supports ocean life

Review - waterWhat type of bond is

between “O” and “H” of the same water molecule?

1. What type of bond is the bond between “O” of

one water molecule and

“H” of another water molecule?2. What is the bond’s name?

covalent

1. Covalent2. Hydrogen bond

What property caused by

hydrogen bonds allows water

strides to walk on water?Surface

tensionWhat is cohesion?

Water molecules stick together What is adhesion?

Water molecules stick to other materials

What happens with the structure

when water changes to ice?Molecules spread apart

and rearrange into crystal structure

What is denser?

Ice or liquid water?Water, that

is why ice floats in

liquid water.

Solutions and MixturesSolution

molecules of one substance are evenly dispersed among the molecules of another

substance.

Mixture two or more substances are intermingling, yet retain their individual

characteristics water suga

r

Visually you cannot tell there are two different molecules – water and sugar

oil vinegar

Visually you can tell there are two different molecules – oil and vinegar

Solutions water suga

r

SOLVENT• The more

abundant substance in a solution

• Usually a liquid• Water is great

solvent

SOLUTE• The substance

being dissolved

solvent

solute

What do you think? Is seawater solution or mixture? What is the solute and what is the

solvent?

Review -Solutions and MixturesWhen molecules of one

substance are evenly dispersed among the molecules of another

substance, it is called…

When two or more substances are intermingling, yet retain their individual characteristics, it is

called…

Water + sugarCan you visually tell there are two

different molecules – water and sugar?

yes

Oil + vinegar

Can you visually tell there are two different molecules – oil and vinegar?

solution

mixture

What is an example of a

mixture?

What is an example of solution?

no

In water-sugar solution, what is solute?

In water-sugar solution, what is solvent?

sugar

water

SalinityIs the total quantity (or concentration) of all

dissolved inorganic solids called ions

• In seawater there are several dissolved salts such as NaCl (sodium chloride) and KCl (potassium chloride)

• Salinity of seawater measures concentration of NaCl, KCl and other dissolved salts

• Salinity is expressed in parts per thousand (symbol ‰ )• The ocean’s average salinity is 35 ‰• Mouths of the rivers entering ocean has salinity near zero• Regions like Red Sea has Salinity more than 40 • To convert salinity to percentages you divide by 10 (for

oceans 3.5%)• Salinity is measured by salinometer (based on the

conductivity of water)

Colligative Properties

• Properties of a liquid that may be altered by the presence of a solute

• The properties are: raising boiling point, decrease freezing temperature, crates osmotic pressure, electrically conductive, slowed evaporation.• Example:• In seawater the solute is NaCl, KCl and other salts• The dissolved salts in the ocean cause saltwater to have a

higher boiling temp than does regular water• As the salinity increases the water resist freezing

Why are seas salty?Salts come from various sources

• Fresh water: from minerals and chemical eroding and dissolving into fresh water which then flows into the oceans

• Waves and surf: help with erosion into the sea• Hydrothermal vents (possible volcanos): bring

minerals into the ocean from the ocean floor • Storms, precipitation and evaporation all have effect

on the amount of salinity that is in the ocean• Salinity and sea water seem to be at a constant (chemical

equilibrium)• Although pH is relatively stable, it changes with depth. It is

due to the amount of Co2 which tends to vary with depth.

Review What is salinity?

Is the total quantity (or

concentration) of all dissolved

inorganic solids called ionsHow is salinity

expressed?Parts per thousand (‰)

What is the average salinity of the ocean?

35 ‰

Name example of salt dissolved in the

ocean?NaCl, KCl

What are colligative properties?

Properties of a liquid that may be

altered by the presence of a solute How does solute (salt)

effect the boiling temperature of the

seawater?

How does solute (salt) effect seawater

freezing ?

The boiling temperature of

seawater is higher than

regular water

Increased salinity causes

seawater to resist

freezing Name 3 examples where oceans get their saltiness?Fresh water,

waves and surf, hydrothermal

vent and volcanoes,

storms, precipitation

and evaporation

Diffusion and osmosisIs the tendency for a liquid, a gas, or a solute to

flow from an area of high concentration to an area of low concentration

Diffusion

A great example of diffusion is movement of molecules across a cell

membrane

High concentra

tion of molecule

Low concentra

tion of molecule

Movement of molecules from high to low

Heat can speed up

the rate of diffusion

Diffusion and osmosis

is diffusion of water through a semipermeable membrane from an area of lower concentration of water to the area of higher

concentration of water

Osmosis

Semipermeable membrane only allows some molecule cross

• High concentration of molecule (e.g. sugar)

• low water concentration

• Low concentration of molecule (e.g. sugar)

• high water concentration

Osmosis = Movement of water molecules from high to low

Membrane will not let molecules of solute across

Diffusion and osmosisArea with higher concentration of

solute (e.g. sugar) is

considered

HYPERTONIC

Area with lower concentration of

solute (e.g. sugar) is

considered

HYPOTONIC

hypertonic

hypotonic

Diffusion and osmosis

Hypertonic = high solute, low

water

Hypotonic =low solute,

high water

Let’s assume cell membrane allows movement of both, solute and waterDiffusion

• Movement of solute from high solute concentration to low solute concentration

• From hypertonic to hypotonic

Osmosis• Movement of water from

area of high water concentration to area of low water concentration

• From hypotonic to hypertonic

diffusion

osmosis

Becomes isotonic(iso=sa

me)

Becomes isotonic(iso=sa

me)

In isotonic solution• No change

In hypotonic solution

• Water enters cell

• Cells swell and burst

In hypertonic solution• Water moves

outside of the cells

• Cells shrivels

Cells in solutions

Passive and active transportPassive

transport• No energy

needed• Molecules

move via diffusion

• Movement from area of higher concentration to lower concentration

Active transport

• Needs energy• Movement

from area of lower concentration to higher concentration

high

low

low

high

energy

ReviewWhat is

diffusion?

What is osmosis?

Movement of liquid, gas or solute from

hypertonic to hypotonic

The area on left is?

The area on right is?

hypotonic – low solute concentration and high water

concentrationhypertonic – high solute concentration and low water

concentration

Movement of water from high

water concentration to

low water concentration

diffusion

osmosis

What is semipermeable

membrane?Membrane that allows only some molecules

to cross

What happens to cells when they are placed in

1.hypotonic or 2.hypertonic solution?1. Cells swell and

burst2. Cells shrinkWhat is passive

transport?

What is active transport?

Diffusion across membrane from high to

low concentration, needs no energy

Movement of molecules across membrane from

low to high concentration, needs energy


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