Butler 6 Cycles in Nature Test Review

Rhythms of Life

100

100: What term describes internal timing systems that keep organisms in sync with the environment?

• (Answer expected: Biological clocks)

200

200: What are daily rhythms called for animals active during the day?

• (Answer expected: Diurnal)

300

300: Name one environmental cue that resets biological clocks so organisms don't get out of step.

• (Answer expected: The sun / light / weather)

400

400: Give an example of an annual rhythm and explain why it happens yearly.

• (Answer expected: Migration — occurs yearly due to seasonal changes; or hibernation/estivation tied to seasons)

500

500: Explain lunar rhythms and give one example of a tidal rhythm organism behavior.

• (Answer expected: Rhythms controlled by the moon; example — crabs coming out at low tide)

Hibernation & Estivation

100

100: What is the term for deep sleep that helps animals survive cold winter months?

• (Answer expected: Hibernation)

200

200: During hibernation an animal’s metabolism and body temperature do what?

• (Answer expected: Metabolism slows and body temperature drops)

300

300: What is estivation and when does it occur?

• (Answer expected: Deep sleep/adaptation to hot, dry months of summer)

400

400: Which of these animals are listed as true hibernators in the text: bears, bats, or ground squirrels? Explain briefly.

• (Answer expected: Ground squirrels and bats are true hibernators; bears sleep but are not true hibernators because they wake up to loud noises)

500

500: Describe two similarities and one key difference between hibernation and estivation.

• (Expected: Similarities — both are deep sleeps, both are adaptations, both reduce heartbeat and metabolism; difference — hibernation is for cold months, estivation is for hot/dry months)

Nitrogen Cycle

100

100: What gas makes up nearly 78% of Earth's atmosphere but cannot be used directly by most plants?

• (Answer expected: Nitrogen)

200

200: What process or organisms change atmospheric nitrogen into forms plants can use? Name one natural way.

• (Answer expected: Nitrogen fixation by bacteria or by lightning)

300

300: What is the name of the step where ammonium becomes nitrates usable by plants?

• (Answer expected: Nitrification)

400

400: Explain why bacteria are the most important part of the nitrogen cycle (two reasons).

• (Answer expected: Bacteria perform fixation, nitrification, ammonification, and denitrification — they convert nitrogen into usable forms and recycle it from dead matter and waste)

500

500: Describe what could happen to an aquatic ecosystem if too much nitrogen runs into it.

• (Answer expected: Excess nitrogen causes algal blooms; at night/algal decay they use up oxygen, causing low oxygen (hypoxia) and killing aquatic animals)

Carbon & Oxygen Cycle

100

100: What process do plants use to convert CO₂ and water into carbohydrates (sugars)?

• (Answer expected: Photosynthesis)

200

200: During respiration, animals release which gas back into the atmosphere?

• (Answer expected: Carbon dioxide)

300

300: Explain why photosynthesis and respiration are balanced on Earth over time.

300: Explain why photosynthesis and respiration are balanced on Earth over time.

400

400: Give two ways humans add carbon dioxide into the atmosphere shown in the diagram.

• (Answer expected: Auto and factory emissions / burning fossil fuels)

500

500: Describe how dead organisms can eventually contribute to fossil fuels.

• (Answer expected: Dead organisms and waste are buried and compacted over long time, forming fossils and fossil fuels that store carbon)

Water Cycle

100

100: What is the process that changes liquid water to water vapor (gas)?

• (Answer expected: Evaporation)

200

200: What process occurs when water vapor cools and becomes liquid droplets to form clouds?

• (Answer expected: Condensation)

300

300: What term describes water released from plant leaves into the atmosphere?

• (Answer expected: Transpiration)

400

400: List the sequence of the main steps of the water cycle from water heating to return to large bodies of water.

• (Answer expected: Evaporation → Condensation → Precipitation → Runoff/Collection)

500

500: Explain why the total amount of water on Earth stays roughly the same even though water changes forms and locations.

• (Answer expected: Water cycles through evaporation, condensation, precipitation, runoff, and collection — nutrients and water are recycled; the state and location change but total quantity stays nearly constant)