Science 7Science 7

Unit 1Unit 1 : : Interactions Interactions within ecosystemswithin ecosystems

Section 1.1 – Levels of LifeSection 1.1 – Levels of Life

• Organism : living things

• Individual : one organism

• The first 3 levels of life are: – individual -- population -- community

Population vs. CommunityPopulation vs. Community

Population : a group of individuals of the same species, living together in one place at one time.

CommunityCommunity

• Community: is made up of all the populations that live in one area

( = not all the same).

• Members of a community interact with one another in different ways.– Can you give me some examples?

• Species : a group of organisms who can successfully reproduce among themselves.

• Habitat : a particular place where a species lives.

Living VS Non-livingLiving VS Non-living

• Biotic = all living things (ex: plants, humans, animals)

• Abiotic = lifeless things ( ex: soil, water, sun)

AdaptationAdaptation

• AdaptationAdaptation: an inherited characteristic that helps an organism survive and reproduce in its environment.

Section 1.2 –Section 1.2 –EcosystemsEcosystems

EcosystemsEcosystems

• The interactions between abiotic (non-living) features of an area and the biotic community that lives in that area.

- Ecosystems contain individuals, populations, and communities.

Abiotic-Biotic Interactions in an Abiotic-Biotic Interactions in an ecosystemecosystem

• 1) The Sun – why is it important?

The SunThe Sun

• Provides light

• Provides heat / warmth

• Provides energy

• Provides food for plants (photosynthesis)

Abiotic-Biotic Interactions in an Abiotic-Biotic Interactions in an ecosystemecosystem

2) Water – why is it important in an ecosystem?

WaterWater

• Plants need water to grow

• Helps with digestion, breathing, and circulating food particles throughout the body

• Provides a habitat for certain species

WaterWater

• Most organisms are made up of 50% to 95% water

• Humans are made up of 70% water

Abiotic-Biotic Interactions in an Abiotic-Biotic Interactions in an ecosystemecosystem

• 3) Air – what is its function in an ecosystem?

AirAir

• Contains oxygen, which animals breathe

• Provides carbon dioxide, which plants use to make their own food.

• Provides a habitat / way of travel for insects and animals

Abiotic-Biotic Interactions in an Abiotic-Biotic Interactions in an ecosystemecosystem

• 4) Soil – why is it important?

SoilSoil

• Provides a habitat for insects and animals

• Provides a ground for humans to build houses and buildings on

• Contains minerals and other nutrients for plants

• Where we find roots for most plants

• Keeps plants and trees in place

Finding ways to travelFinding ways to travel

• Are most plants, trees and flowers planted by humans?

• If they are not planted by humans, how do plants manage to start growing?

Finding ways to travelFinding ways to travel

• Their seeds are transported by:– Wind– Water– Animals

– Many plants have special adaptations that help their seeds spead to new areas.

1.3 Sampling Ecosystem Populations

How can we count every type of species or organisms in an ecosystem?

Is it harder to count organisms in a smaller ecosystem or in a larger ecosystem?

Sampling

Sampling = method used to estimate population size in ecosystems

How is it calculated?

Choose a small area that is representative of the ecosystem.

Then count the features of that smaller area (plants, trees, animals, insects)

Multiply the result by the size of the whole area.

Example

If there are 10 cows per square meter in a field.

The field is 20 meters square. Multiply 20 by 10 (200) to find out

how many cows approximately should be in the field.

Quadrat

Biologists use many ways to sample ecosystems.

The most popular is the quadratquadrat.

Quadrat

Is a square tool used to measure and observe a small and representative section of a larger area.

Features inside the quadrat are counted and used to estimate the number of features in the whole ecosystem.

Section 1.4Section 1.4

Climates and BiomesClimates and Biomes

What is the weather like today?

– Look outside, what’s the weather like?

– What is the forecast calling for tomorrow? And what about the rest of the week?

What’s the difference…

• …between weatherweather and climateclimate?

– Give me some examples of weather and climates.

Weather

– refers to the local conditions that change from day to day, or even from hour to hour.

• Example: rain in the morning, but sunny in the afternoon.

Climate

– refers to the average weather pattern of a region.

• Example: in northern Canada, it is very cold, the winters are long & harsh, and the summers are short & cool

Climate

– To know the climate of a region, we take an average of the weather over a longer period of time, such as 30 or 40 years.

• We use temperature, precipitations, pressure, humidity, and the number of sunny days per year.

Climate

– Earth can be divided into distinct regions based on climate.

• Example: regions around the equator are very warm, and regions close to the poles are very cold

Climate

– Similar climates have similar types of soil and get similar amounts of yearly precipitations.

– This encourages similar types of plants to grow in them.

Biome

• A biomebiome is a large area with characteristic climate, soil, plants, and animals.

• Each type of biome can be found in different parts of the world.

Biome

• In an airplane…

– if you flew over a region unknown to you, and you saw elephants, giraffes, and lions… where do you think that would be?

– Africa (savannah biome)

Biomes

• In an airplane…

– if you flew over a region unknown to you, and you saw deer, foxes, owls, moose, and seagulls... where do you think that would be?

• Canada (forest biome)

Biomes

• In an airplane…

– if you flew over a region unknown to you, and you saw an area with cactuses, camels, and sand… where do you think that would be?

• The Australian Outback (desert biome)

Biomes

– Biomes are the 5th level of living (or biological organization).

– Biomes contain many ecosystems.

Biomes

• The land on Earth can be divided into 6 major biomes.

– Unlike ecosystems, there are not many different types of biomes

in the world.

The World’s Biomes

• Tundra• Boreal forest• Temperate forest• Tropical rain forest• Grassland• Desert

Canada’s Biomes

• Tundra• Boreal forest• Temperate forest• Grassland

In New-Brunswick…

• Which biome(s) can we see in N.B.?– Boreal forest– Temperate forest

The World’s Biomes• Tundra• Boreal (Coniferous)forest• Temperate (Deciduous)forest• Tropical rain forest• Grassland• Desert• Temperate Rainforest (Western North

America), • Prairie Grasslands (North America), • Savannah (African Serengeti),

The Desert Biome

• Deserts cover about 1/5 of the Earth’s surface

• They occur where rainfall is less than 50 cm/year.

Soil in the desert

• Most deserts have a specialized vegetation, and a specialized vertebrate and invertebrate animals.

• Soils often have abundant nutrients because they need only water to become very productive and have little or no organic matter.

Weather in the desert

– Disturbances are common in the form of occasional fires or cold weather, and sudden, infrequent, but intense rains that cause flooding.

Animals in the desert

• There are few large mammals in deserts because most are not capable of storing sufficient water and standing the heat.

• The dominant animals of warm deserts are vertebrates, such as reptiles. Mammals are usually small.

• Deserts often provide little shelter from the sun for large animals.

Tropical Forest Biome

• Tropical forests are characterized by the greatest diversity of species.

• They occur near the equator.

Tropical Forests

• One of the major characteristics of tropical forests is their distinct seasonality: rainy season and dry season

Soil in Tropical Forests

• Soil is nutrient-poor and acidic. Decomposition is rapid and soils are subject to heavy leaching.

Weather in Tropical Forests

• Temperature is on average 20-25° C and varies little throughout the year.

• Precipitation is evenly distributed throughout the year, with annual rainfall exceeding 2000 mm.

Animals in Tropical Forests

• Animals include numerous birds, bats, small mammals, and insects.

• Flora is highly diverse.– Trees are 25-35 m tall, with big

trunks and shallow roots, mostly evergreen, with large dark green leaves. Plants such as vines,ferns, mosses, and palms are present.

Temperate Forest Biome

– Temperate forests occur in eastern North America, northeastern Asia, and western and central Europe.

Temperate Forests

• Well-defined seasons with a distinct winter characterize this biome.

• Moderate climate and a growing season of 140-200 days during 4-6 frost-free months distinguish temperate forests.

Soil in Temperate Forests

• Soil is fertile, enriched with decaying litter.

Weather in Temperate Forests

• Temperature varies from -30° C to 30° C.

• Precipitation (75-150 cm) is distributed evenly throughout the year.

Animals in Temperate Forests

• Animals include: squirrels, rabbits, skunks, birds, deer, mountain lion, bobcat, timber wolf, fox, and black bear.

Flora in Temperate Forests

• Flora is characterized by 3-4 tree species per square kilometer.

• Trees are distinguished by broad leaves that are lost every year and include such species as oak, maple, elm, willow, etc.

Boreal Forest Biome

• Boreal forests, represent thelargest biome.

Boreal Forest Biome

• They can be found in Europe, Asia and North America (Alaska and Canada).

• Seasons are divided into short, moist, and moderately warm summers and long, cold, and dry winters.

Soil & Weather in Boreal Forests

• Soil is thin, nutrient-poor, and acidic.

• Temperatures are very low (colder).

• Precipitation is primarily in the form of snow, 40-100 cm annually.

Flora in Boreal Forests

• Flora consist mostly of cold-tolerant evergreen conifers with needle-like leaves, such as pine, fir, and spruce.

Animals in Boreal Forests

• Animals include: hawks, moose, bear, lynx, fox, wolf, deer, hares, chipmunks, and bats.

Boreal Forests

• Current extensive logging (cutting down trees) in boreal forests may soon cause their disappearance.

Tundra Biome

• Tundra is the coldest of all the biomes.

Tundra

• Tundra is a treeless plain.

• It is frost-molded landscapes, extremely low temperatures, little precipitation, poor nutrients, and short growing seasons.

Characteristics of Tundra

• Extremely cold climate • Low biotic diversity • Simple vegetation structure • Limitation of drainage (water)• Short season of growth and

reproduction • Energy and nutrients in the form of

dead organic material

Animals of the Tundra

• Well adapted to handle long, cold winters and to breed & raise young quickly in the summer.

• Many animals hibernate or migrate during the winter because food is not abundant.

• Reptiles and amphibians are few or absent because of the extremely cold temperatures.

Animals of the Tundra

• Mammals: mountain goats, sheep, elk, caribou, hares and squirrels

• Birds: ravens, falcons, loons, snow birds, and gulls

• Insects: beetles, grasshoppers, butterflies, mosquitoes, flies, moths, blackflies

• Fish: cod, flatfish, salmon, and trout

Weather of the Tundra

• The average winter temperature is -34° C , but the average summer temperature is 3-12° C which allows this biome to sustain life.

• Rainfall may vary in different regions of

the arctic. Yearly precipitation, including melting snow, is 15 to 25 cm.

Soil of the Tundra

• A layer of permanently frozen subsoil called permafrost exists, consisting mostly of gravel and finer material.

• When water saturates the upper surface, ponds may form, providing moisture for plants.

• There are no deep root systems, but still a wide variety of plants that can resist the cold climate.

Grassland Biome

– Grasslands are characterized as lands dominated by grasses rather than large shrubs or trees.

Grassland (Prairies)

• http://www.ucmp.berkeley.edu/glossary/gloss5/biome/grassland.html

Which Biome is this?

• Grassland

Which Biome is this?

• Temperate Forest

Which Biome is this?

Desert

Which Biome is this?

• Boreal Forest

Which Biome is this?

• Temperate Forest

Which Biome is this?

• Desert

Which Biome is this?

Grassland

Section 1.5Section 1.5The biosphereThe biosphere

The The BiosphereBiosphere

The The biospherebiosphere refers to all of refers to all of the places on Earth where life the places on Earth where life can exist and interact with the can exist and interact with the physical environment.physical environment.

The 3 parts of the biosphereThe 3 parts of the biosphere

1.1. The The hydrospherehydrosphere is all the water on is all the water on Earth, including oceans, rivers, and Earth, including oceans, rivers, and lakes.lakes.

2.2. The The lithospherelithosphere is the solid mineral is the solid mineral material that covers the Earth, material that covers the Earth, including the soil.including the soil.

3.The 3.The atmosphereatmosphere is the air that is the air that surrounds both the hydrosphere and surrounds both the hydrosphere and the lithosphere.the lithosphere.

• The biosphere is a giant ecosystem. The biosphere is a giant ecosystem.

• The biosphere is the 6The biosphere is the 6thth level of living. level of living.

Chapter 2:Chapter 2:

How organisms How organisms interactinteract

2.1 Food Chains2.1 Food Chains

What are food chains?What are food chains?

– A food chain is a model which shows A food chain is a model which shows how energy is stored in food passes how energy is stored in food passes from organism to organism.from organism to organism.

– In a food chain, arrows show the In a food chain, arrows show the direction in which energy flows direction in which energy flows through the chain.through the chain.

Food Chains - examplesFood Chains - examples

Sun Sun →→ Grass Grass →→ Grasshopper Grasshopper →→ Bird Bird → → CatCat

Food Chains - examplesFood Chains - examples

Sun Sun →→ Grass Grass →→ Cows Cows →→ HumansHumans

Energy FlowEnergy Flow

How does energy move through a food How does energy move through a food chain?chain?

At each step along the chain, energy is At each step along the chain, energy is taken in by an organism.taken in by an organism.

Some of this energy fuels the organism, Some of this energy fuels the organism, and it is burned up and released as and it is burned up and released as heatheat..

Energy Flow Energy Flow (continued)(continued)

Some energy is stored in the Some energy is stored in the organism’s body tissues, while some organism’s body tissues, while some energy cannot be used and passes energy cannot be used and passes out of the animal as waste.out of the animal as waste.

EnergyEnergy Flow Flow

For example:For example:– A cow eats several kilograms of grass in A cow eats several kilograms of grass in

one day. However, the cow does not one day. However, the cow does not gain mass equivalent of the grass it gain mass equivalent of the grass it eats.eats.

– Why not?Why not?

Energy Flow:Energy Flow:

Energy flow is the movement of Energy flow is the movement of energy, starting from the Sun, and energy, starting from the Sun, and passing from one organism to the passing from one organism to the next.next.

In a food chain, very little energy In a food chain, very little energy that is stored in one organism is that is stored in one organism is passed on to the next organism.passed on to the next organism.

The Role of Organisms in The Role of Organisms in Food ChainsFood Chains

1)1) ProducersProducers: :

– produce food for themselves and produce food for themselves and others, using the Sun’s energy and others, using the Sun’s energy and nutrients in soil and air.nutrients in soil and air.

– Producers make life possible for all Producers make life possible for all other organisms.other organisms.

– Examples: plants, algaeExamples: plants, algae

2.2. ConsumersConsumers::

– consume (eat) the food made by the consume (eat) the food made by the producers.producers.

– Consumers come in all sizes and Consumers come in all sizes and shapes.shapes.

– Examples: fish, animals that eat other Examples: fish, animals that eat other animals.animals.

The organism next to the producer The organism next to the producer always feeds on plants or algae.always feeds on plants or algae.

3) 3) HerbivoresHerbivores::

– Plant-eating animals.Plant-eating animals.

– Examples: cows, rabbits, deerExamples: cows, rabbits, deer

4) 4) CarnivoresCarnivores::

– Meat eating organisms.Meat eating organisms.– Eat the producers, and other consumers.Eat the producers, and other consumers.– Examples Examples : lynx, cod, dragonflies: lynx, cod, dragonflies

5) 5) OmnivoresOmnivores::

– Eat plants & meat.Eat plants & meat.– Examples Examples : bear, human, raccoon: bear, human, raccoon

6)6) Predators: Predators:

– Are animals that kill and eat other Are animals that kill and eat other animals.animals.

– Usually only eat meat, but some will eat Usually only eat meat, but some will eat anything if food is in short supply.anything if food is in short supply.

– ExamplesExamples: wolves, hawks, sharks: wolves, hawks, sharks

7) 7) PreyPrey: :

– Is the animal being eaten by another.Is the animal being eaten by another.

Review for quiz 2.1Review for quiz 2.1

AnswersAnswers

p. 47 #1. p. 47 #1. a) a) ProducerProducer: make food for themselves and others, using : make food for themselves and others, using

the Sun’s energy and nutrients in soil and air.the Sun’s energy and nutrients in soil and air.

b) Cb) Consumeronsumer: consume (eat) the food made by the : consume (eat) the food made by the producers.producers.

c) c) OmnivoreOmnivore: organisms that eat plants & meat.: organisms that eat plants & meat.

d) d) PredatorPredator: animals that kill and eat other animals.: animals that kill and eat other animals. Usually only eat meat, but some will eat anything if food is in short Usually only eat meat, but some will eat anything if food is in short

supply.supply.

→ → The definitions are also in your notes, or on pages The definitions are also in your notes, or on pages 38-40 in the textbook. 38-40 in the textbook.

p. 47 #2.p. 47 #2. Grass Grass → insect → small bird→ insect → small bird Grass → hare (rabbit) → snakeGrass → hare (rabbit) → snake Grass Grass → hare → eagle→ hare → eagle Grass Grass → deer → lynx→ deer → lynx Grass → mouse → snakeGrass → mouse → snake Grass → mouse → eagleGrass → mouse → eagle Seeds → small bird → eagleSeeds → small bird → eagle Seeds Seeds → mouse → snake→ mouse → snake

Answers will vary. If you are unsure, raise your Answers will vary. If you are unsure, raise your hand, and I will come check. hand, and I will come check.

p. 60 #1.p. 60 #1.

ProducerProducer: grass, plants, leaves, seeds, : grass, plants, leaves, seeds, mushrooms, fruit, vegetables, algae, aquatic mushrooms, fruit, vegetables, algae, aquatic plants, …plants, …

Consumer - herbivoreConsumer - herbivore: hare, horse, cow, : hare, horse, cow, cetain insects, deer, …cetain insects, deer, …

Consumer - carnivoreConsumer - carnivore: lynx, lion, eagle, : lynx, lion, eagle, snake, wolf, frog, shark, …snake, wolf, frog, shark, …

→ → Many different examples exist.Many different examples exist.

p. 60 #4.p. 60 #4.

If one (or more) organism (s) in an ecosystem If one (or more) organism (s) in an ecosystem are removed, there will be a shortage of food are removed, there will be a shortage of food for the consumers. for the consumers.

If the consumer cannot find food, it will die of If the consumer cannot find food, it will die of hunger and may disappear himself.hunger and may disappear himself.

* Your answers will vary. If you need help, raise * Your answers will vary. If you need help, raise your hand and I will come over to verify your your hand and I will come over to verify your answer.answer.

2.1 - Food Webs2.1 - Food Webs

A A Food WebFood Web is a combination of many is a combination of many different food chains, showing the different food chains, showing the relationships between and among many relationships between and among many different producers and consumers in an different producers and consumers in an ecosystem.ecosystem.

Food Web- exampleFood Web- example

Section 2.3 Section 2.3

Energy Transfer and Energy Transfer and Pyramid of NumbersPyramid of Numbers

2.3 – Food Pyramid2.3 – Food Pyramid A A Food PyramidFood Pyramid is a model representing the numbers of is a model representing the numbers of

organisms consumed at each successive level of the organisms consumed at each successive level of the pyramid.pyramid.

The size of the level indicates the number of organisms at The size of the level indicates the number of organisms at that level. There are always more animals being eaten that level. There are always more animals being eaten than are eating.than are eating.

To find out how much energy is being transferred from one To find out how much energy is being transferred from one level of the pyramid to the other, we look at the total of all level of the pyramid to the other, we look at the total of all the organisms in the ecosystem. the organisms in the ecosystem.

As you move up the pyramid, there are less organisms. As you move up the pyramid, there are less organisms. The most energy is found at the base, where the The most energy is found at the base, where the producers are.producers are.

Food Pyramid- exampleFood Pyramid- example

2.4 - Succession2.4 - Succession

How Ecosystems Change over TimeHow Ecosystems Change over Time

The gradual process by which some The gradual process by which some species within an ecosystem replaces species within an ecosystem replaces other species is called other species is called successionsuccession..

Primary SuccessionPrimary Succession

Primary successionPrimary succession is the gradual growth is the gradual growth of organisms in an area that was previously of organisms in an area that was previously bare –like a rocky slope. bare –like a rocky slope.

Organisms to first appear (called Organisms to first appear (called primary primary speciesspecies) are those that can cling to the rock ) are those that can cling to the rock and grow, such as mosses and lichens. and grow, such as mosses and lichens.

Other organisms use the nutrients to begin Other organisms use the nutrients to begin to grow.to grow.

Examples of areas in which a Examples of areas in which a community has never lived before community has never lived before would be:would be:

new lava or rock from a volcano that makes new lava or rock from a volcano that makes a new island or a new landscapea new island or a new landscape

a sand bar that arises from shifting sands in a sand bar that arises from shifting sands in the oceanthe ocean

exposure of igneous rock surfaces by a exposure of igneous rock surfaces by a land slideland slide

a meteor makes a depression that fills with a meteor makes a depression that fills with rainwater or fresh water from underground rainwater or fresh water from underground streams.streams.

Secondary SuccessionSecondary Succession

The gradual growth of organisms in an area The gradual growth of organisms in an area after a disturbance, such as a fire, or when a after a disturbance, such as a fire, or when a large tree falls, is known as large tree falls, is known as secondary secondary successionsuccession..

Examples of secondary succession include:Examples of secondary succession include: • • A farmer’s fieldA farmer’s field • • a vacant city lota vacant city lot • • a newly forested areaa newly forested area • • a strip minea strip mine

Chapter 3

Section 3.1:

Cycles of the biosphere

The Water Cycle

The Water Cycle

• An apple is composed of what percentage of water? – 84% water

• A carrot is composed of how much water? – 88%.

• What about a tomato? – 94%

• The human body is about 70% water.

The Water Cycle

• All living things require water.

• Water is used for life processes such as supplying food throughout an organism’s body in a form it can use in its cells, and carrying away wastes from those cells.

The Water Cycle

• Water cycle: is the continuous movement of water through the biosphere.

• There are 4 main processes in the cycle:– Evaporation– Transpiration– Condensation– Precipitation

The Water Cycle

1. Evaporation:– Is the process of changing a liquid into a

vapour. Liquid water evaporates to form invisible water vapour.

– Example: when laundry in hung in the sunlight, the water evaporates until the laundry is dry.

The Water Cycle

– As well, solid water (ice) can change directly into water vapour without going through the liquid stage (=sublimation).

– Example: Ice cubes will shrink in size if the ice-cube tray is left in the freezer for too long. The solid ice cube shrinks as it sublimates into invisible water vapour.

The Water Cycle

2. Transpiration:

– Is the process in which water that is taken in through a plant’s roots evaporates from the plant’s leaves, stem, and flowers.

The Water Cycle

3. Condensation:– Is the process of changing a vapour into

liquid.

– Warm air contains water vapour. As air cools, it is able to hold less and less water.

– Condensation happens when air becomes so cool that it can no longer hold as much vapour, and liquid water is released.

The Water Cycle

• The liquid forms clouds, fog, or dew.

The Water Cycle

4. Precipitation:– Is the process in which liquid water

forms from condensation occurring inside clouds, and then falls as rain, freezing rain (sleet), snow, and hail.

The Water Cycle

• The first two processes – evaporation and transpiration – move water up from the Earth into the atmosphere.

• The second two – condensation and precipitation – return water to Earth.

The Water Cycle

• Ground water: is water in the soil.

– Plant roots can grow down to reach ground water. People can reach ground water by digging wells.

• Run-off water: is water that runs off the ground into lakes, rivers, or streams.

The Carbon Dioxide and Oxygen Cycle

• Another major cycle constantly occurs on Earth.

• The carbon dioxide and oxygen cycle: is the process by which carbon dioxide and oxygen are cycled and recycled in the biosphere.

Respiration

• Respiration: is the oxygen-using process that takes place in the cells of living things to get the energy out of food.

• When you breathe, you take in oxygen. Your body cells use this oxygen, to release energy from food.

Respiration

• All living things – both animals and plants – must respire (breathe) all the time.

• Fish, algae, and plants in the water also breathe.

• So do decomposers – bacteria, fungi, and moulds.

Respiration

• In addition to energy, respiration has two other products: carbon dioxide and water.

• Carbon dioxide is a gas made up of carbon dioxide and oxygen.

• Plants need carbon dioxide, along with other substances, to make their own food (=photosynthesis).

The Cycle of life

• The water cycle and the carbon dioxide and oxygen cycle are continuous processes in our environment. Without them, there would be no life on Earth.

• But humans can break or interrupt these cycles.

• Technology can be used to recreate or fix these damaged cycles that are necessary for so many organisms.