Activator:Compare & Contrast

Food Webs and Food Chains(hint: page 91 Science

textbook)

Activator:Write a paragraph comparing

and contrastingnekton, plankton, and benthos organisms.

(at least 5 sentences)

HYDROSHERE

Yo Dude, where did all this water

come from?

Do you know these Properties of Water?• Polarity – positive or negative charge of a molecule• Cohesion – water molecules like to stick together• Surface tension – a force that acts on the particles at

the surface of a liquid and causes them to held together tightly (like skin on the water)

• Adhesion – water likes to stick to other substances• Solvent – a substance in which another

substance dissolves.• Universal solvent – water dissolves more substances

than any other substance• Density – measure of the mass of a substance per

unit volume (how tightly packed it is)• Buoyancy – ability of a fluid to exert an upward force

on an object in (Does it float?)• Specific heat – amount of energy needed to raise the

temperature of 1 kg of a substance by 1° Celsius (The unit is Joule per kg per degree Celsius (J/kg · °C) ) It takes water a long time to heat up or cool down.

Water Molecules and Polarity• Water (H20) is a simple molecule of two hydrogen (H)

molecules and one oxygen (O) molecule bonded together.

• Oxygen has a stronger attraction than hydrogen does, so oxygen has a strong pull towards its nucleus that pulls electrons closer. This gives the water molecule a small negative charge near the oxygen atom and a small positive charge near each hydrogen atom. This gives the water molecule an uneven charge which is called its polarity.

• This causes water molecules to be attracted to each other. These bonds are called cohesion. They hold water molecules together although they are weak and tend to break easily. (when something is dropped in the water, it goes in)

• Surface tension is an example of cohesion. It is like a skin at the water’s surface. This allows water spiders to scoot across the surface of the water without falling in.

Adhesion• Adhesion is the tendency of water to stick

to other substances. • When you add water to a glass, you can

see it higher on the sides than it is in the middle. This is because the water is sticking to the side of the glass, making it higher.

• This curved surface (shaped like a U) is called a meniscus.

Why is water so special?• Water is a universal solvent since it can

dissolve more substances than any other liquid. This is because of its polarity (uneven positive and negative charges of the water molecule).

• Water molecules attract and bond with ions (negatively charged particles) to make compounds (mixtures).

• This property is why water makes up most of many plants, animals, and other organisms (including people). The essential nutrients we need dissolve in water and travel to the cells to keep us alive.

DENSITY • Density is how tightly packed something is.

Higher density means it is tightly packed, lower density means it is more loosely packed.

• Density changes with temperature. For example, as you heat water the density decreases because the molecules spread out. This is why colder water is on the bottom of the ocean. Sunlight heats water on the top and causes the molecules to become less dense toward the surface.

• Density changes with physical state. Most substances become more dense as they freeze since the particles become packed together. Water expands (becomes) bigger when it freezes. Ice has a greater volume and lower density than water. Ice floats because it is less dense than water.

BUOYANCYBuoyancy happens because there is an

upward force on objects in water causing some of them to float.

If the upward force (buoyant force) is greater than the downward force (gravitational force), it floats.

If something is less dense than water, it will float. (Wood, oil, and wax)

If something is more dense than water, it will sink. (metals)

Metal boats can float because they are made so they have pockets of air. This air helps to lower the density of the boat enough so it will float.

SPECIFIC HEAT• The amount of heat it takes to raise the

temperature of 1 kg of a substance by 1° Celsius.

• The unit is joule per kg per degree Celsius ( J/kg · °C )

• The specific heat of water is very high – 4,184 J/kg · ° C

• This means it takes a long time for water to change temperature.

• This high specific heat of water helps to keep your body at a stable temperature. (98.6° F)

WHAT IS THE HYDROSPHERE?Structure of the Hydrosphere

Hydrosphere – the part of the earth that contains waterSalinity – the concentration of salts dissolved in a liquid (How salty is it?)Glacier – a mass of ice and snow that moves slowly over the EarthGroundwater – water located below the Earth’s surfaceAquifer – a rock layer that stores water and allows water to flow through itWetland – land areas that remain wet for all or most of the yearWatershed – an area of land where rain collects and drains into one collection place, often a lake or an oceanRiver – large, flowing stream of waterTributaries – smaller streams that drain into a riverLake – low area of land into which surface water run-off drains

WHERE IS THE EARTH’S WATER?• Water covers about 71% of the Earth’s surface.

(The other 30% of the Earth’s surface is dirt.)• 97% of the Earth’s water is salt water found in the

oceans.• The remaining 3% is fresh water.• Fresh water is found: *69% frozen in polar ice caps, glaciers, snow,

and permafrost (frozen ground) *30% liquid water in ground water *1% in lakes, wetlands, rivers, and the

atmosphere

OUR GLOBAL OCEAN• All of the Earth’s ocean water is

connected.• Continents divide this ocean into 4 parts:

* Pacific Ocean – largest and deepest, deepest part is Marianas trench (11,033 m deep), at the US west coast

* Atlantic Ocean – second largest, half the volume of the Pacific Ocean, at the US east coast

* Indian Ocean – third largest between Africa, Australia, and Asia

* Arctic Ocean – smallest and much is covered by ice

OUR FRESHWATER RESOURCES• Most of the Earth’s fresh water is frozen

in the polar ice caps• Nearly 1/3 of the Earth’s fresh water is

groundwater• Drinking water often comes from

aquifers• Earth’s surface waters flow through

watersheds as they travel to a low area to collect such as lakes or oceans

• Some major lakes of NC are Lake Mattamuskeet, Lake Phelps, Lake Waccamaw, and Lake Michie

WHAT IS UP WITH THIS OCEAN THING, ANYWAY?

OCEAN RESOURCES AND OCEANOGRAPHY• Natural resources – materials from the

environment that are used by living things• Respiration – oxygen is used to release the

energy stored in food (after breathing)• Photosynthesis – a process by which plants

use light energy from the sun to make nutrients in the form of water and carbon dioxide (H20 + CO2)

• Desalinization – a process used to separate salt from seawater

• Oceanography – study of the physical properties of oceans

• Sonar – (SOund NAvigation and Ranging) method of determining the depth of the ocean using echoes

HOW DO WE GET OXYGEN TO BREATHE?

• Plants and people (as well as anything that breathes air) have a special relationship where we help each other survive

• We need oxygen (O2) to breathe and when we breathe out, we exhale carbon dioxide (CO2).

• Plants need carbon dioxide (CO2) for photosynthesis to produce nutrients to survive. They get rid of oxygen (O2) after photosynthesis.

OOOH, THIS WATER TASTES SALTY!

• In parts of the world where it is hard to get fresh water, people have to get the salt out of the salty ocean water so they have fresh water to drink. This is called desalination.

• Ocean water is boiled. The evaporated water is captured from the air where it is cooled. The salt is left behind.

HOW DEEP IS THE OCEAN?• SONAR is used to find out how deep the ocean

is.• Sonar equipment on a ship sends a sound down

into the water. They see how long it takes for the sound to bounce back from the bottom of the ocean. (The faster the sound comes back, the shallower the water.)

• Since they know how fast sound travels in water, they can tell how deep the water is.

• This helps scientists make maps of the ocean floor. They can find features such as underwater mountains, canyons, and trenches. They can even track tectonic plate movement.

• Scientists also use (ROV’s) remotely operated vessels to see what is very deep in the ocean. These do not have people on board, but they have cameras and other equipment. This helps them gather more detailed information.

WHERE DO ORGANISMS LIVE IN THE OCEAN?MARINE ECOSYSTEMS

Benthos – organisms that live on or near the ocean bottom, sometimes attached to surfacesPlankton – tiny organisms that are moved by ocean currentsNekton – larger free-swimming organisms that don’t depend on currents to move them aroundIntertidal zone – the shoreline area falls between the high tidemark and the low tidemark (gets wet during high tide)Neritic zone – the ocean area that slopes down from the edge of the shoreline toward the ocean floorCoral reef – limestone deposit formed from coral shellsUpwelling – the movement of nutrient-rich waters from the deep ocean into shallow areas, brings nutrients that help some kelp forests thrive.Oceanic zone – made up of the open waters of the ocean (extends from the ocean’s surface to its deepest point)Hydrothermal vents – cracks in the ocean crust that release mineral-rich water that has been heated inside the earthEstuary – special ecosystem where salty ocean water mixes with fresh water from rivers (salinity changes constantly)

WHAT LIVES IN THE OCEAN?

• Organisms that live in the ocean fall into 3 groups. These groups are defined by how they move and where they live in the ocean. Can you describe these groups?

• Group 1 – Benthos• Group 2 – Plankton• Group 3 – Nekton

ANSWERS

I HOPE I AM AT THE TOP OF THE FOOD CHAIN!!FOOD WEBS: LAND AND WATER

Producer – an organism that makes its own foodConsumer – an organism that eats other organismsDecomposer – an organism that breaks down and eats dead organismsTrophic level – each feeding level (example: producer, primary consumer, secondary consumer, decomposer) in an ecosystemFood chain – the flow of energy from one organism to another in an ecosystemFood web – this shows the connected network (web) of food chains within an ecosystemEnergy pyramid – the flow of energy in an ecosystem that shows how energy available to consumers decreases as the trophic levels increase. (Coach, p. 155)

CONNECTIONS BETWEEN LAND AND WATER

Terrestrial food webs show feeding relationships in a land ecosystem.

Aquatic food webs show feeding relationships in a water ecosystem.

For example, if an insect emerges from a stream and is eaten by a bird, energy is transferred from the stream ecosystem to the land ecosystem. P. 154

Grizzly bears eat fish, etc. Can you think of any more?

HOW CAN I TELL IF THIS WATER IS CLEAN?

EVALUATING WATER SYSTEM HEALTHpH – the measurement of how acidic or basic water isTurbidity – how clear water is (high turbidity means unclear water, low turbidity means clear water)Algal bloom – rapid growth of algae caused by too many nutrients in the water (also causes high turbidity)Nitrates – nitrogen compounds used for growth by plants and algae (fertilizer)Bio-indicators – organisms or parts of organisms that are used to check the health of an ecosystem

HEALTHY WATER SYSTEM• A HEALTHY WATER SYSTEM HAS

MODERATE TO COOL TEMPERATURES, HIGH DISSOLVED OXYGEN, LOW ACIDITY (pH), AND CLEAR WATER (LOW TURBIDITY)

• COOLER WATER HOLDS MORE OXYGEN

• CHARTS ON PAGES 159 AND 160

OOOOH, HIGH TECH GADGETS!!!TECHNOLOGY AND THE HYDROSPHERE

Remote sensing – scientists use satellites to monitor all areas of the earth (p. 162)Global positioning system (GPS) – use of satellites to pinpoint locations on the earthGeographic information system (GIS) – mapmaking software that creates different map layers for the same area (Each layer tells something different about the area – location of watershed, for example)

SOMEBODY CLEAN UP THIS MESS!!!

HOW HUMANS AFFECT WATERPollutant – any substance or form of energy that can cause harm to the environment Point-source pollution – if you can point to the source of the pollution (there is proof of only one source of pollution)Non-point-source pollution – pollution that comes from many similar places or a source that is not easily identified (you can’t pinpoint one specific source of pollution)

SOMETHING STINKS, PEW!!PROTECTING WATER RESOURCES

Wastewater – water that runs into city drains Wastewater treatment plants – a facility that processes water to remove wastes and then releases the clean water into a lake or streamSeptic system – a wastewater treatment system for an individual home or farmDrain field – a series of pipes with small holes that are buried under rocks that help to filter the wastewater from a home to make it clean. Small microorganisms also help clean the water so it can go into the ground and be used again.