Unit B-Chapter 2-Lesson 2

How Do Solutions Form?

Forming Solutions

• A solution is a mixture in which the particles of different substances are evenly distributed and are too small to see with the naked eye.
• A solution appears as a single substance.
• The formation of a solution is a physical change.
• The substances that make up the solution retain many of their original properties.

Example:

• When sugar is dissolved in water, its sweet taste remains.

A solvent is a substance that dissolves other materials

A solute is a substance that is dissolved.

Example:

• In a solution of Kool-Aid, the water is the solvent and the sugar flavoring powder is the solute.

All solutions have solvents and solutes.

Types of Solutions

Some common examples of solutions are:

• perfumes
• cooking extracts
• gasoline
• air
• sterling silver
• tooth fillings
• carbonated beverages (such as soda)

• In a solution, the solvent or solute can be solid, a liquid, or a gas.
• Metal alloys are solutions of solids in solids.
• The metals are melted and mixed, and when they harden, the resulting substance looks uniform.
• These alloys are useful because they combine the properties of different metals.

Examples:

Carbonated beverage = carbon dioxide (solute) + water (solvent)

Brass = copper (solute) + zinc (solvent)
Dental Fillings = mercury (solute) + silver (solvent)

A dilute solution describes a solution with a small amount of solute compared to the amount of solvent

Example:

• Kool-Aid with more water than flavoring.

A concentrated solution describes a solution with a large amount of solute compared to the amount of solvent.

Example:

• Kool-Aid with extra flavoring mixed with the water.

Dissolving Faster

• Because the solution process depends on contact between particles of the solvent and particles of the solute, any action that increases the number of collisions between the solvent and the solute particles tends to increase the rate of dissolving.
• Both stirring and heating the solution increase the rate of collisions.
• Breaking the solute into smaller pieces increases the rate of disolving by increasing the surface area of the solute,
• Icreased surface area allows more solvent particles to come in contact with more solute particles.
• Heating the solvent increases the speed of the solvent particles, and they collide with the solute with greater force, knocking particles away from the solute.
• The increased motion of the solvent particles acarries away more solute particles, leaving fresh surface areas exposed.
• Particles in a heated liquid are spaced farther apart, so there is more space between them for solute particles.
• In general, more solute dissolves in a solvent at higher temperatures than at lower temperatures.

Unit B-Chapter 2-Lesson 1

How Does Matter Change State?

States of Matter

Matter exists in three states:

• Solid
• Liquid
• Gas

A solid has a definite shape and definite volume
Example: Ice

A liquid has a definite volume, but no definite shape
Example: Water

A gas has no definite shape or volume.  It will occupy the volume of whatever container it is in.
Example:  Steam

• In a solid, particles of matter are very close together and are held together by the attraction of the particles for one another.
• When a solid, such as ice, is heated, its particles move faster and farther apart.  When the substance reaches its melting point, the solid changes to a liquid.
• Eventually the particles gain enough energy to escape.  When the particles reach this point, the substance becomes a gas.
• All three states of matter exist on earth.

Melting and Boiling

• Although most substances normally exist on Earth in just one state, all materials can exist as solids, liquids, or gases.

Example:
On the surface of Venus, which is very hot, lead would be a liquid rather than a solid as it is on Earth.

• The state of a substance depends on its temperature and the amount of attraction between its particles.
• The temperature at which a substance changes from a solid to a liquid state is called its melting point. 
• Melting occurs because particles gain heat.
• When the particles in a liquid lose energy, they move more slowly. 
• If the substance is cool enough, the particles slow down to the point where the liquid becomes a solid.
• The temperature at which a liquid changes to a solid is called its freezing point.
• In pure substances, melting and freezing occur at the same temperature.

Boiling and Evaporation

• If a liquid is heated enough, all the particles in the liquid eventually will have enough energy to break free at the surface. (The liquid changes to gas)
• The temperature at which this occurs is called the boiling point.
• Different substance have different boiling points.
• A substance can change from liquid to a gas through evaporation.
• Evaporation is the change in state from a liquid to a gas at the surface of a liquid.
• Evaporation can occur at any temperature because some of the particles at the surface always have sufficient energy to escape.
• However, evaporation takes place more quickly in hotter liquids.
• The change of state from a gas to a liquid is called condensation.

Unit A-Chapter 4-Lesson 5

What Are The Features of Water Biomes?

Saltwater Biomes

The saltwater biome is a water biome that has a high salt content
The saltwater biome is the largest of all the earth's biome.

• it can be divided into three zones:

1. Shallow Ocean Zone
2. Ocean Surface Zone
3. Deep Ocean Zone

• The shallow ocean zone along the coasts makes up only a small part of the saltwater biome.
• Sunlight reaches the sea bottom in this zone, and the water temperature remains relatively constant
• Sunlight penetrates the top few hundred meters of the ocean surface zone.  Here, photosynthesizing plankton are the primary producers; consumers include tuna, sharks, whales, and ocean birds.
• Plankton are microscopic, free floating organisms that serve as food for larger organisms.
• The deep ocean zone consists of everything deeper than 100 meters.
• Too little sunlight penetrates the cold waters of the deep ocean zone to support photosynthetic organisms.
• Most animals in the deep ocean eat other animals or feed on detritus that drifts from the sunlit waters above.

Freshwater Biomes

Freshwater biomes have a low salt content and can be divided into two types:

1. those with standing water, such as lakes and ponds
2. those with flowing water, such as rivers and streams

• Lakes are usually larger and deeper than ponds and may be deep enough to have a colder, deeper layer that receives little or no sunlight.
• Most organisms live in the upper, sunnier part of the lake.
• Producers include floating and shallow-water plants.
• Consumers include fish, insects, frogs, beavers, and birds.
• Decomposers live at the bottom of the lake.

• Rivers and streams have moving water.
• The quick flow of water oxygen to the water, which allows certain organisms such as trout to live there.
• Insect larvae, algae, and worms live on rocks in the streams.

• Water plants are able to take root in areas of a stream where water flows more slowly.

Estuaries

• In an estuary biome, fresh water from the rivers or streams mixes with slat water from the ocean.
• Water in an estuary is usually warmer than ocean water and contains less salt.
• Salt content changes with tides; During high tides, more ocean water flows in, so the water is saltier than when the tide is out.

• Estuaries are important breeding grounds for fish, shellfish, and birds.
• Fish and shellfish release their eggs in estuaries because there is plenty of plankton available on which the hatchlings can feed.

• Migratory birds such as geese and ducks rest and feed in estuaries.

Unit A-Chapter 4- Lesson 4 Notes

What Are The Features of Land Biomes?

Biomes

Biomes are large geographic regions with a particular kind of climate and community.

The plant communities that grow in any biome largely determine the types of animal communities that live there.

A particular type of biome may occur in a number of places around the world.

Climate changes with latitude. 

• Biomes near the equator have warm, relatively unchanging climates
• Biomes at mid-latitudes have marked seasonal changes.
• Biomes near the poles have the coldest climates with the shortest summers and longest winters.

Altitude affects climate; temperatures drop as altitude increases.

Land Biomes

Tundra
The tundra is the northernmost and coldest biome.

During summer months only a few centimeters of ground thaw; the ground below remains frozen year-round.

Permafrost is ground that is permanently frozen.

Most tundra palnts are small.

Examples of animals in the tundra include ducks, geese, caribou, and lemmings.

Taiga
The taiga is a forest biome just south of the tundra, characterized by conifers.

The taiga is also called the coniferous forest biome because it is dominated by coniferous tress such as spruce, pine, and fir.

Examples of animals in the taiga include moose, black bears, and elk.

Temperate Deciduous Forest

The temperate deciduous forest is a forest biome characterized by trees that lose their leaves each year.

Examples of trees include maples, beeches, and oaks-that lose their leaves in autumn.

Temperate deciduous forest have four distinct seasons.

Examples of animals in the temperate deciduous forest include deer, snakes, birds, and insects.

Grassland

The grassland is a biome characterized by few trees and many grasses.

The soil is fertile becuase each year the tops of grasses die and decompose returning nutrients to the soil.

Many cereal grains are produced on the grasslands.

Examples of animals include coyotes, bison, rabbits, and praire dogs.

Tropical Rain Forest

The tropical rain forests are biomes that have much rainfall and high temperatures all year.

Tropical rain forests are found near the equator. 

More species of organisms live in the rainforests than in any other land biome.

Fruits, nuts, and spices come from the rainforest-as well as cacao, which is used to make chocolate.

Examples of tropical rain forest animals include parrots, monkeys, sloths, snakes, frogs, and butterflies.

Desert

The desert is a biome with little rainfall and usually high daytime temperatures.

Some deserts may be sandy; others rocky.

Desert organisms have adaptations, cuch as water storage abilities, that help them survive extremely dry conditions.

Scorpion

Examples of desert animals include roadrunners, scorpions, meerkat, ans ostrich.

Unit A-Chapter 4-Lesson 3 Notes

What Happens When an Ecosystem Changes?

Environmental Changes

• Change is a natural part of the history of any ecosystem.
• Changes may be long-term-for example, the result of fires, droughts, and floods- or long-term, as a result of climatic change.
• All organisms have a certain range of tolerance for conditions such as:

1. Environmental temperature
2. Amount of moisture 
3. Amount of light

• Organisms cannot usually survive in conditions that are outside their range of tolerance.
• In any ecosystem, populations change as conditions change.
• New communities of organisms, which are better adapted to new conditions in that ecosystem, may replace original communities.

Competition

   
• Organisms can live in an ecosystem only as long as it meets their needs for food, water, shelter, and other essentials. 
• Organisms that live within an ecosystem often compete for similar resources.
• This competition occurs among different kinds of organisms, as well as among members of the same species.
• Competition helps regulate population size because as competition for resources increases, population size decreases.
• When resources are limited, organisms that are well-adapted to the conditions in an ecosystem will be best able to compete for resources and survive.
• Some animals solve the problem of limited resources by migrating.
• The snowy owl, for example, inhabits the Arctic tundra, but when the population of lemming-their main food source-falls, it may migrate great distances in search for food. 
• In the winter, snowy owls are sometimes sighted as far south as Illinois.

People Affect Ecosystems

• Ecosystems change naturally, but human activities such as cutting down trees and draining wetlands can speed up the change.
• People can also change the ecosystems by introducing new species that out-compete native species.
• Conservation of resources and restoration practices can help to reduce and repair ecosystem damage.

Unit A-Chapter 4-Lesson 2

How Are Materials Recycled?

Oxygen-Carbon Dioxide Cycle

• Water is one of the most important materials required by an organism.

Photosynthesis, green plants use energy from the sun to convert carbon dioxide and water into sugar and oxygen.

• Photosynthesis = Carbon dioxide + Water + Energy ->Sugar + Oxygen

Respiration is an energy-producing process in which a cell combines oxygen with sugars and gives off carbon dioxide and water.

• Respiration = Sugar + Oxygen -> Carbon Dioxide + Water + Energy

• Plants carry out both photosynthesis and respiration.

The Nitrogen Cycle

• All living things need nitrogen to make proteins. 
• Although 80% of the air consists of nitrogen gas, few living things can use nitrogen in this form.
• Nitrogen gas must first be changed into one of a variety of nitrogen compounds and cycled through the environment.

Nitrogen gas can be converted into forms usable by living things in two ways:

1. Nitrogen-fixing bacteria that grow in the root nodules of legume plants such as peas, soybeans, and clover combine nitrogen in the air with hydrogen to form nitrogen compounds that plants can use to make proteins.
2. Lightning can cause nitrogen gas to combine with oxygen in the air to form nitrogen compounds that return to the earth in rain or snow.

When the compounds of protein are broken down during decomposition, nitrogen is returned to the air as nitrogen gas.

Pollution Affects the Cycles

• Human activities can disturb the natural recycling of oxygen and carbon dioxide. 
• The burning fossil fuels, for example, results in increased levels of carbon dioxide in the air.
• Excess carbon dioxide and other "greenhouse" gases absorb infrared radiation coming from the  earth's surface and trap this heat in the atmosphere, which could result in an eventual overall increase in the earth's average temperature.

Unit A-Chapter 4-Lesson 1 Notes

How Do Organisms Interact?

Interactions Within Ecosystems

All living and nonliving parts of an ecosystem interact.

Some interactions are direct, such as when a person picks a peach from a peach tree and eats it.
Other interactions are indirect.  A honeybee and a person may have no direct interactions, but the honey bee might have pollinated the peach flower and so played a role in the production of the peach.

To survive in a particular ecosystem, organisms must be adapted to the environmental conditions of that ecosystem.

A healthy ecosystem is one which the living and nonliving parts are balanced.

Producers, Consumers, and Decomposers

Green plants are producers; using energy from the sunlight to make their own food through the process of photosynthesis. 

Organisms that cannot make their own food are called consumers.  Consumers may be herbivores, carnivores, or omnivores.

A herbivore is a consumer that eats only plants or other producers.

A carnivore is a consumer that eats only animals

An omnivore is a consumer that eats both producers and consumers.

A decomposer is an organism that obtains energy by consuming dead organisms and the wastes of living organisms.

In general, plants are producers, and animals are consumers.

However, one special producer is not a plant; its a type of bacteria that grows on the ocean floor.
This type of bacteria depend on sulfur-containing bacteria(sulfides) from deep ocean vents to release energy and make food.

Food Webs

Food chains describe how energy moves in an ecosystem from one organism to another.  

Green plants (producers) are the bottom link in a food chain.  Consumers make up the next links, followed by decomposers.

Different food chains combined form a food web.

Energy Pyramids

An energy pyramid is a model that shows how energy is used in a food chain or an ecosystem.

The amount of energy available to a certain group of organisms depends on which level of the energy pyramid it is on. 

Less energy is available at any level in the pyramid  than in the level below.  The top of the pyramid has the least amount of energy.