Ecology and Biological Cycles Quiz

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Questions and Answers

What does ecology focus on?

The study of ecosystems only

The structure of biological molecules

The interactions between organisms and their environment (correct)

The genetic makeup of individual species

What does the reductionistic approach in the hierarchy of life imply?

Biological structures do not interact with one another.

Complex biological systems can be understood only by observing the whole.

Complex systems have no individual parts.

A complex system is the result of its individual components. (correct)

Which of the following best describes the scale of ecological study?

Only microscopic and sub-microscopic levels

Only large ecosystems, disregarding individual species

From molecular to global scales (correct)

Primarily person-to-person interactions

Which statement is NOT true about the hierarchy of life?

It focuses solely on cellular biology. Signup and view all the answers

How does ecology include the interactions among organisms?

By examining both biotic and abiotic factors in an environment Signup and view all the answers

What is the primary distinction between a habitat and a niche?

A habitat is the specific location where an organism lives, while a niche defines its role and relationships. Signup and view all the answers

According to the Competitive Exclusion Principle, what largely contributes to the decline of one species in the presence of another?

Differences in adaptability between two species in an identical niche. Signup and view all the answers

Which of the following best defines carrying capacity?

The maximum number of organisms an ecosystem can support, influenced by various factors. Signup and view all the answers

What are the two main factors that support population growth towards its biotic potential?

Biotic factors (biological) and abiotic factors (physical and chemical). Signup and view all the answers

In ecological terms, what is meant by 'source' and 'sink' functions?

Source is the resources needed for survival, while sink refers to waste assimilation abilities of the ecosystem. Signup and view all the answers

What is the process by which nitrates are formed from nitrogen-containing protein molecules in animal waste?

Nitrification Signup and view all the answers

Which substance is primarily washed into the soil from rock during the phosphorus cycle?

Phosphate Signup and view all the answers

What role do denitrifying bacteria play in the nitrogen cycle?

They convert nitrate back to atmospheric nitrogen. Signup and view all the answers

How does phosphorus return to the soil after the death of plants and animals?

It is released during decomposition by bacteria and fungi. Signup and view all the answers

What happens to phosphorus when aquatic organisms die?

It is released into the surrounding water. Signup and view all the answers

Over time, what geological process can expose phosphate rock to the atmosphere?

Upheaval Signup and view all the answers

What essential environmental factor is NOT mentioned as being important for the survival of organisms?

Happiness Signup and view all the answers

What is the primary function of soil bacteria in the nitrogen cycle?

To break down urea and produce nitrates. Signup and view all the answers

Which biome is characterized by a broad-leafed forest and abundant precipitation of at least 75 centimeters annually?

Deciduous Forest Signup and view all the answers

What climate characteristic is typical for the tropical rainforest biome?

Heavy daily rainfall with a dark forest floor Signup and view all the answers

Which type of vegetation is essential for survival in the savanna biome during dry seasons?

Drought- and fire-resistant plants Signup and view all the answers

In which geographical locations are tropical rainforests primarily found?

South America and Central America Signup and view all the answers

What is the average rainfall range for the savanna biome?

100 to 150 centimeters per year Signup and view all the answers

Which of the following are abiotic factors that affect survival and reproduction?

Temperature Signup and view all the answers

Which of the following is a density independent factor?

Natural contamination Signup and view all the answers

What phase comes after the explosive (logarithmic) phase in population growth?

Deceleration phase Signup and view all the answers

Which major factor does NOT influence population size in a density dependent manner?

Natural disasters Signup and view all the answers

What is primary succession?

Succession occurring on previously lifeless areas Signup and view all the answers

In an S-curve, what is the first phase of population growth called?

Establishment phase Signup and view all the answers

What describes biological succession?

Orderly replacement of one community by another Signup and view all the answers

Which of the following factors would be classified as density dependent?

Competition Signup and view all the answers

Study Notes

Ecology

Ecology studies interactions between organisms and their environment.
It explores how organisms interact amongst themselves and with the environment.

Biological Organization / Hierarchy of Life

Complex biological structures and systems define life, using a reductionist approach.
This approach states that a complex system is the sum of its parts.
The study of life ranges from the microscopic scale of molecules and cells to the global scale of the living planet.

Nitrogen Cycle

When animals consume food, amino acids are broken down, forming urea.
Urea is excreted as waste and contains nitrogen.
These nitrogen-containing protein molecules are then broken down (decomposed) by soil bacteria into nitrates, a process called nitrification.
All nitrogen in plants, animals, soil, and water eventually returns to the atmospheric reservoir via denitrifying bacteria.

Phosphorus Cycle

Raindrops dissolve phosphate in rocks, transporting it into the soil where it becomes a plant nutrient.
Phosphorus atoms then pass into plants and animals, and upon death are decomposed by bacteria and fungi.
This releases phosphorus back into the soil, where it can be taken up by other plants or washed into streams.
Aquatic organisms absorb phosphorus, and when they die, it is released back into the water.
Freshwater phosphorus eventually flows into oceans, settling on the seabed and forming part of the sediment.
Over millions of years, sediment can form phosphate rock, which is then exposed to the atmosphere through geological processes like upheaval.
Weathering and erosion release phosphorus from the rock back into the soil.

Law of Tolerance

An organism's survival depends on essential factors in its physical environment.
These factors include water, temperature, oxygen, and nutrients.
These factors can vary and are not constant.

Habitat and Niche

A habitat is the organism’s "address," where it lives.
A niche is the organism's "job" or functional role – what it does, its relationship to food and enemies.

Competitive Exclusion Principle

Two species of plants or animals cannot occupy the same ecological niche indefinitely.
The population of one species will decline to zero due to intense competition for resources, even if they are equally adapted to the niche.

Carrying Capacity

The number of organisms an ecosystem can support.
Determined by factors like food supply, nesting sites, water supplies, and the ecosystem's ability to assimilate waste.

Population Growth and Decline

Biotic (biological) and abiotic (physical and chemical) factors stimulate growth, allowing a population to reach its biotic potential.
Biotic potential refers to the maximum reproductive rate.
Finding food and escaping predators are biotic factors that favor survival and reproduction.
Light and temperature are abiotic factors.

Density Independent Factors

Limit population growth regardless of the number of organisms present in a habitat.
Examples include drought, heat waves, cold spells, storms, floods, and natural contamination like silt.

Density Dependent Factors

Influence population size based on the density of a population.
Major density-dependent factors include predation, competition, parasitism, and disease.

Biological Succession

The gradual replacement of one community of organisms by another in a predictable manner.
Ecosystems are dynamic due to organisms growing and dying, populations fluctuating, and conditions changing over time.

S-Curve

Represents population growth, characterized by four distinct phases.
Establishment phase: The population is small and growing slowly.
Explosive (logarithmic) phase: The population grows rapidly with abundant resources.
Deceleration phase: The population growth slows down due to limited resources.
Dynamic equilibrium phase: The population stabilizes, fluctuating around the carrying capacity.

Primary Succession

The process of succession in previously lifeless areas.
Examples include lava-covered slopes, landslide rubble, and open-pit mine waste heaps.

Deciduous Forest

A broad-leafed forest biome covering parts of North America, Europe, China, Japan, and Australia.
Characterized by high precipitation (at least 75 centimeters) and a fairly long growing season.

Tropical Rainforest

Located in warm equatorial regions with yearly rainfall exceeding 200 centimeters.
Predominantly found in Central America, South America's Amazon and Orinoco, Africa’s Congo River basin, Madagascar, and Southeast Asia.
Heavy daily rainfall during the rainy season.
A dark and poorly vegetated forest floor.
Layered or stratified canopy structure with tree crowns at multiple levels.
Abundant and diverse animal life.

Savanna

Warm-climate grasslands with scattered trees.
Found primarily in South America, Africa, India, and Australia.
Average rainfall of 100 to 150 centimeters per year.
Wet and dry seasons alternate, with fires common during dry spells.
Plants are drought and fire resistant, like baobab and thorny acacia trees.

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Description

Test your knowledge on ecology, biological organization, and the nitrogen and phosphorus cycles. This quiz covers key concepts of how organisms interact with their environments and the essential cycles of nutrients in ecosystems. Dive in to understand the intricate relationships that sustain life on our planet.