Unit 2 CBA Review/Study Guide

Unit 2 Lesson 1 What Makes Earth a Habitable Planet?

A habitable planet has abiotic (nonliving) factors and characteristics that are “just right” for allowing life to exist. In

our solar system, Earth is the only known planet at this time with factors that are just right for allowing life to exist. Factors that allow life on Earth:

liquid water

distance from Sun (93 million miles or 150 million km)

- if Earth was closer it would be too hot - if Earth was further away it would be too cold

temperature (0 OC - 100 OC) that allows for liquid water

to exist thicker atmosphere that protects us from harmful solar

radiation

Earth’s atmosphere also contains elements and

compounds (in a gaseous form), such as nitrogen (N), oxygen (O2), and carbon dioxide (CO2), needed to sustain life

Unit 2 Lesson 2 Review/Study Guide

Dichotomous Keys

Biologists -scientists who study life and living organisms. Sometimes biologists may observe an organism that is not known to them. To help identify the unknown organism, biologists use a tool called a dichotomous key. Dichotomous key: is a series of choices (paired statements) based on observations of physical characteristics. The choices start with broad questions in which the object fits into one of two categories. The next choice subdivides each of the broad questions. Each set of questions becomes more specific until the name of the object is reached.

3

1 Which of the following is most helpful for identifying an organism using a dichotomous key? A Its average lifespan

B Its sources of food

C Its habitat

D Its physical structures

2 A drawing of a leaf and a dichotomous key are provided.

What leaf is shown in the drawing?

A Liquidambar

B Magnolia

C Pine

D Redbud

3 An illustration of two insects is provided.

Which of the paired statements could be used to distinguish the insects using a dichotomous key? A Has 6 legs Has 8 legs B Large hind legs Small hind legs C 2 pairs of spots on wing cover 3 pairs of spots on wing cover D Antennae absent Antennae present

Unit 2 Lesson 3 Review/Study Guide

Microhabitats

Biotic factors = living things in an environment (plants/animals) Abiotic factors = nonliving things in an environment (sunlight, air, soil, water, temperature, rocks, etc.) Habitat -the environment, or natural home, of plants, animals, and other organisms

Microhabitat -smaller in size or a more specialized habitat *The area under a dead tree, a portion of a drainage ditch, shade under a tree, or other small areas are examples of microhabitats. Even though microhabitats are small areas, they are complex and a challenge to study. Environmental conditions such as the amount of light, availability

of food, temperature, and moisture determines the variety of organisms found in microhabitats. Entomologists -scientists who study insects and their relatives. A Berlese funnel trap is used to collect organisms living in leaves, ground cover, and the soil. A bright, warm light is placed above the funnel to encourage the organisms to move. Once they fall into the trap, it is easier to observe the organisms and record information.

Other tools useful for studying microhabitats can include: hand lens, insect trap, thermometer, digital camera, ruler, tweezers, and hand shovel.

Berlese Funnel Trap

Unit 2 Lesson 4 Review/Study Guide

Environments and Organisms

Biome -a large region of the world that is distinguished by similar climate and organisms.

There are 6 major land biomes of the world: tundra,

taiga, temperate forest, tropical rain forest, grassland, and desert.

o Tundra : Located in an Arctic area of extremely cold temperature 25 cm or less precipitation per year Receives the least amount of sunlight of all biomes Ground is frozen most of the time (permafrost) Poor soil quality Plants include: low growing grasses, shrubs, mosses Animals include: migratory birds, wolves, polar bears,

foxes, and caribou

The Tundra has the least variety of plants and animals of all 6 biomes.

o Taiga :

Also called the coniferous forest Located just south of the Tundra 25 cm – 125 cm of precipitation per year Poor soil quality Plants include: pine trees, spruce trees, fir trees and

hemlock Animals include: moose, elk, bears, beavers, deer, birds,

lynx and fox

o Temperate Forest :

Also called the deciduous forest Located eastern and western regions of U.S., eastern

Europe, and western regions of Asia 75 cm – 125 cm of precipitation per year Soil quality is rich with organic matter Plants include: oak trees, hickory trees, elm trees and

maple trees Animals include: deer, bears, snakes, rabbits, squirrels,

and variety of birds and insects

o Tropical Rain Forest : Located generally along the equator More than 200 cm of precipitation per year Receives the greatest amount of sunlight of all biomes Poor soil quality Plants include: giant trees, vines, and flowers Animals include: monkeys, squirrels, bats, snakes, birds,

rodents, and insects The Tropical Rain Forest has the greatest variety of plants

and animals of all 6 biomes.

o Grasslands: Also call Prairies, Pampas, and Savannahs Located throughout the world 25 cm – 75cm precipitation per year Very rich soil Plants include: primarily grass Animals include: prairie dogs, mice, bison, foxes, zebras,

gazelles, hyenas, and wildebeests

o Desert :

Located throughout the world Less than 25 cm of precipitation per year Receives a large amount of sunlight (though some deserts

are cold) Poor soil quality Plants include: cacti, small shrubs, and wildflowers Animals include: jackrabbits, rodents, bats, snakes,

toads, and insects

Climograph –graph used to communicate the average

monthly temperature and precipitation in one graph.

o The bar graph represents the precipitation data using the

left y-axis

o The line graph represents the temperature data using the

right y-axis

Below are 2 of the 6 example climographs you have in your notes. Make sure you can interpret the amount of precipitation and the temperature for any given month.

Tundra

Least variety of organisms

o The tundra has the least variety of species due to the very short growing season, low precipitation,

and extremely harsh temperatures.

Tropical Rain Forest

Greatest variety of organisms

o The tropical rain forest has the greatest variety of species due to the year-round growing season, high precipitation, and warm temperatures.

Texas is a very large state and contains a variety of

ecoregions. Ecoregions -areas of similar environmental conditions such as climate and landforms. Smaller than biomes, ecoregions are home to distinct species and natural communities of organisms.

o A diverse ecoregion will have a large numbers of individual

organisms and variety of species.

1 Which conclusion is best supported by the information provided in the Biome S

and Biome T tables?

A Both biomes receive the largest amount of precipitation in the warmer months.

B Biome T receives more solar radiation than Biome S.

C Biome T is less likely to have a wide variety of plants due to the climate.

D Biome S is most likely a desert, and Biome T is most likely grassland. 2 Which biome is likely to have the greatest variety of plants and animals?

A Tundra

B Desert

C Temperate forest

D Tropical rain forest

3 Which climograph would support the greatest variety of organisms?

A

B

C

D

Unit 2 Lesson 5 Review/Study Guide

Flow of Energy

The Sun is the ultimate source of energy. The Sun is where the energy for ecosystems originates. During photosynthesis, plants produce sugar (chemical energy) that is stored for later use. Animals consume plants and use the chemical energy obtained from sugar to go about their daily activities.

Feeding relationships in an ecosystem: Producers/plants (also called autotrophs): make their own food using the energy of the sun Consumers/animals (also called heterotrophs): get their food by eating other organisms

- herbivores are consumers that eat producers (plant-eaters)

- carnivores are consumers that eat other consumers (meat-

eaters) - omnivores are organisms that feed on both producers and

consumers (plant and meat-eaters)

Decomposers (fungi/bacteria/earthworms, etc.) are organisms that break down dead tissue, returning chemicals and nutrients to the ground

Food chain -a simple model that shows the path of energy from

the Sun to the producer to a series of consumers in an ecosystem. The arrows in a food chain indicate the flow of energy.

Food webs -a combination of overlapping food chains and also represent the flow of energy.

Food webs are a more realistic model since they show many possible feeding relationships.

Energy

Source

producer

1st -level

consumer

herbivore

2nd

-level

consumer

carnivore

Energy pyramid -used to show the amount of energy, or food

that is available to another organism at the next level of a food chain. It is a visual model reminding us that producers at the bottom of the pyramid have greater energy available than the other organisms.

10,000

Units

1000

Units

100

Units

10

Units

10% Rule

Organisms use 90% of the energy they

obtain from their energy source during

life processes.

For this reason, only about 10% of the

energy present at one feeding level is

passed to the next feeding level.

This is known as the 10% rule.

4 If there are 100,000 units of energy available from the kelp, approximately how much energy is available for the sea otters?

A 1 unit

B 100 units

C 1000 units

D 10,000 units

Unit 2 Lesson 6 Review Study Guide

Biodiversity

Biodiversity -the variety of plants and animals in an ecosystem. Sustainability -ecosystem’s health and ability to survive over a long period of time.

An increase in diversity of an ecosystem increases the

chance of survival of the organisms that the ecosystem or habitat supports. Organisms have more “resources”.

Increase biodiversity = increase sustainability

Decrease biodiversity = decrease sustainability

Unit 2 Lesson 7 Review/Study Guide Cycling of Matter

What would happen if trash were not collected and people did not recycle any materials? The world would be a mess. We would have more trash than living space, and we would be depleting Earth’s natural resources. Eventually we could run out of the resources we depend on to live. Think WALL-E.

Conservation -the wise use of natural resources. Without conservation efforts, reserves of these resources will quickly dwindle. The ways to conserve are referred to as “The Three R’s”. Reduce –to use less

Reuse –recovering items that would have been thrown away an finding another use for them Recycle – to convert into reusable material

Earth’s processes naturally recycle matter.

Water Cycle Water falls to Earth as precipitation, collects on the surface and in the ground, evaporates into the atmosphere, turns back into liquid water as condensation (cloud formation), and then returns as precipitation. The water is used over and over.

The Carbon Cycle

Several important processes are part of the carbon cycle: Photosynthesis: plants take in carbon dioxide from the environment (then release oxygen back into the atmosphere). Respiration: most organisms get energy by combing oxygen from the air with food in a process known as cellular respiration. Carbon dioxide is released back into the environment as a waste product.

Decomposition: decomposers (earthworms, isopods, bacteria, etc.) break down the wastes or remains of other living things into smaller molecules. The products of decomposition are simple molecules, such as carbon dioxide and water. The burning of fossil fuels and wood also release carbon dioxide into the atmosphere.

The Nitrogen Cycle

The nitrogen cycle has many steps:

Fish produce waste in the form of ammonia.

There are bacteria that break down ammonia into nitrites.

Different bacteria further break down nitrites into nitrates.

Plants take in the nitrates to carry out life processes and

when the plants die, the nitrates are released in the decomposition process.

This cycle happens over and over again. A very similar process occurs in a terrestrial (land) environment.

1 As material in a compost bin decomposes, the organic

matter-

A remains unchanged in form and composition.

B will always degrade into toxic material.

C is broken down into useful compounds such as

carbon.

D eventually is completely destroyed.

2 Plants use nitrogen for —

A decomposition.

B photosynthesis.

C producing glucose.

D growth and productivity.

3 Nitrogen in the water is changed into a useable form by —

A plants.

B animals.

C bacteria.

D producers.

Unit 2 Lesson 8 Review/Study Guide

Variations within Populations Stimulus –a change that causes an adjustment by an organism (anything an organism can sense).

External stimulus – comes from outside the body(use of the

five senses) Internal stimuli – comes from inside the body (hunger,

thirst, pain, etc.) Response –a change in behavior, physiology, or appearance of an organism (a reaction). Innate behavior – behavior an organism is born with (rattlesnake rattling tail, young offspring nursing, young sea

turtles heading towards ocean, baby birds hatching from their eggs, etc.)

Migration –seasonal movement of animals from one place to another.

Hibernation –a deep sleep in which body systems reduce to minimal levels.

Learned behavior –behaviors that an organism learns from

observation or direct experience (prey learning to stay away from rattlesnake, young offspring learning to hunt, teaching a dog a trick.)

1 Roots grow downward in the soil in response to -

A the external stimuli gravity .

B the internal stimuli gravity.

C the external stimuli the sun.

D the internal stimuli the sun.

2 Thirst is -

A a learned behavior.

B an internal stimuli.

C a form of migration.

D a form of hibernation.

Unit 2 Lesson 9 Review/Study Guide

Many of today’s ideas about evolution are based on the work of Charles Darwin. In the 1850's, Darwin described how organisms might change over time (adapt). Most of these ideas came from observations Darwin made during the five years he worked as a naturalist on the research ship H.M.S. Beagle. A part of his journey, Darwin observed and studied 13 different species of finches living on the Galapagos Islands.

As a result of his studies, he discovered that when species reproduce, the survivors will pass on favorable traits to their offspring. If an offspring did not receive the favorable trait, the offspring will likely die before passing on an unfavorable trait. Natural selection -process by which organisms change over time as those with traits best suited to an environment pass their traits to the next generation Adaptation -an activity or action that helps an organism survive

its environment or surroundings. Examples of adaptations can include:

Spiny/waxy leaves of a plant to prevent water loss

fur color of an animal to blend in to its environment (camouflage)

physical structure of bird beaks to better obtain food

hard shell of a crab to protect it from its predators, etc.

1 Several years of drought affect a population of plants in

southwest Texas. Which of the following characteristics would you expect to see more frequently in the plants over

the next several generations?

A Abundant broad leaves

B Waxy coating on leaves

C Flowers blooming regularly

D Tall, narrow stems

2 A population of birds walks along the shores of a swampy

area eating small crabs. Climactic changes cause the water level in the area to increase. Which genetic variation in the

bird population will be at an advantage leading to greater survival in the area?

A Longer legs for wading

B A thicker coat of feathers

C Shorter, stronger beaks

D Sharper talons on the feet

3 Mudskippers are a species of fish which, over thousands of

generations, have developed adaptations that allow them not only to survive outside of the water, but to actually

travel from one water source to another. What environmental condition most likely led to these

adaptations?

A Lower temperatures

B Frequent droughts

C Larger predators

D Increased precipitation