principles of ecology - powerpoint 4

Questions and Answers

What is a primary advantage of the C4 pathway in plants?

It reduces the need for water by minimizing stomatal opening.

It enhances photosynthetic efficiency at high temperatures. (correct)

It functions solely during the night to maximize CO2 uptake.

It requires less ATP compared to the C3 pathway.

How do CAM plants minimize water loss during photosynthesis?

By using PEPcase to store CO2 as a 4-carbon acid at night. (correct)

By absorbing water directly from the air during daylight.

By maintaining stomatal opening throughout the day.

By always keeping stomates closed to retain moisture.

In what type of environment are CAM plants predominantly found?

Arid and saline environments with limited water availability. (correct)

High-altitude areas with dramatic temperature fluctuations.

Cold temperate regions with high rainfall.

Deep aquatic ecosystems with abundant light.

What triggers some plants to switch from the C3 pathway to the CAM pathway?

Conditions becoming arid or saline. Signup and view all the answers

How does the Crassulacean Acid Metabolism (CAM) support photosynthesis in aquatic environments?

By facilitating CO2 uptake at low concentrations. Signup and view all the answers

What is a characteristic feature of plants using the C4 photosynthetic pathway?

They possess a greater water use efficiency. Signup and view all the answers

Which of the following best describes facultative CAM plants?

They switch to C3 when water is plentiful. Signup and view all the answers

What role does high CO2 concentration have on photorespiration?

It reduces photorespiration rates. Signup and view all the answers

What distinguishes CAM plants from C3 and C4 plants during the day?

They restrict stomatal opening to conserve moisture. Signup and view all the answers

What is one significant feature of morphological adaptations in heterotrophs?

They allow for more effective food acquisition. Signup and view all the answers

What is the primary energy yield of heterotrophs when consuming organic compounds?

Fats are the most energy-rich component. Signup and view all the answers

Why do herbivores typically consume more biomass than carnivores?

Animal cells are less energy-rich than plant cells. Signup and view all the answers

What factor primarily influences the energy content derived from food for heterotrophs?

The chemical composition of the food. Signup and view all the answers

How do archaea, bacteria, and fungi digest their food?

They excrete enzymes into the environment to break down organic matter. Signup and view all the answers

What evolutionary advantage is linked to the development of mobility in animals?

Ability to find food sources. Signup and view all the answers

What type of compounds generally serve as poor energy sources for heterotrophs?

Secondary compounds. Signup and view all the answers

Which of the following adaptations in animals reflects their dietary specializations?

Mouthpart morphologies. Signup and view all the answers

What role do microorganisms play in bioremediation?

They break down harmful chemicals in the environment. Signup and view all the answers

What is a common characteristic of all insects regarding food consumption?

All insects possess paired appendages for food manipulation. Signup and view all the answers

Which organisms primarily depend on excreting enzymes for nutrition?

Archaea and bacteria. Signup and view all the answers

What does it imply when both axes of a plot are log-scaled?

It indicates that the relationship between the variables may involve exponential growth. Signup and view all the answers

Why does the heat produced by metabolism proportionally relate to an organism's volume?

Because the number of cells increases with the volume of the organism. Signup and view all the answers

According to the content, what scaling would be expected for metabolic rate in relation to mass?

B is proportional to M2/3 Signup and view all the answers

What primary limitation is indicated to influence the 3/4 scaling of metabolic rate?

The distribution of materials through channels in the body. Signup and view all the answers

Which of the following statements about scaling is true based on the content?

A larger organism would explode if metabolic rates scaled with volume. Signup and view all the answers

What does the equation B∝M2/3 signify in terms of metabolic scaling?

Metabolic rate is tuned down compared to surface area scaling. Signup and view all the answers

What geometric principle is considered when examining the scaling differences between surface area and volume?

Surface area scales with the square of the radius, while volume scales with the cube. Signup and view all the answers

What is the dimensionality of the distribution channels that facilitate materials throughout the body according to fractal geometry?

4D Signup and view all the answers

Which of the following reflects the concept of metabolic scaling accurately?

Heat dissipation limitations affect metabolic rate scaling. Signup and view all the answers

How does the surface area-to-volume relationship impact larger organisms?

It limits their overall size due to heat retention problems. Signup and view all the answers

What digestive adaptation is primarily found in herbivores to help process fiber-rich diets?

Bacterial symbionts Signup and view all the answers

How do ruminants benefit from rumination?

It allows them to digest food faster and safely Signup and view all the answers

Which of the following choices best exemplifies Kleiber's Law?

Metabolic rates scale allometrically with body mass Signup and view all the answers

What is a primary characteristic of heterotrophy in multicellular animals?

They have specialized tissues for digestion Signup and view all the answers

Which factor does NOT influence an animal's digestive adaptations?

Environmental temperature Signup and view all the answers

What is coprophagy and why is it significant in some herbivores?

Re-ingesting feces for enhanced nutrient absorption Signup and view all the answers

What is the relevance of species' body mass in terms of metabolic rate according to Kleiber's findings?

Larger species have a disproportionately lower metabolic rate Signup and view all the answers

Which type of organisms primarily benefit from a relationship with bacterial symbionts?

Herbivores consuming fibrous plant matter Signup and view all the answers

What physiological process corresponds to 'heterotrophy' in organisms?

Breaking down complex food into simpler molecules Signup and view all the answers

Study Notes

Photosynthetic Pathways

C4 Pathway: Uses more ATP but has better efficiency in high temperatures compared to C3 plants; minimizes transpiration losses by utilizing PEPcase to absorb CO2 when stomates are partially open.
Climatic Patterns: C4 plant dominance is predictable by climate, with increased temperature correlating with a higher proportion of C4 species.
Crassulacean Acid Metabolism (CAM): Opens stomates at night to minimize water loss, using PEPcase to fix CO2 into 4-carbon organic acids, stored in vacuoles for daytime use in the Calvin cycle.
CAM Plant Characteristics: Often succulent and found in arid or saline environments but also in humid tropics as epiphytes and some aquatic plants, improving CO2 uptake in low concentrations.
Facultative CAM: Some plants can switch between C3 and CAM pathways based on water availability, optimizing carbon gain when conditions permit.

Heterotrophy

Definition: Heterotrophs convert energy-rich organic compounds (food) into usable chemical energy (ATP).
Food Chemistry: Energy gain varies based on food chemistry, with carbohydrates, proteins, and fats being the most energy-rich; fiber (e.g., cellulose) is difficult to digest for most heterotrophs.
Energy Cost of Feeding: Soil microorganisms require less energy to find low-energy food, while carnivores, like cheetahs, expend more energy for a high-energy meal.
Digestive Adaptations: Variability in digestive systems allows more efficient assimilation of energy and nutrients; herbivores have longer digestive tracts to process fibrous plant materials.
Symbiotic Relationships: Many herbivores rely on bacteria to assist in cellulose breakdown, exemplified by ruminants with specialized stomach compartments for fermentation and rumination.

Metabolism and Scaling

Metabolism Definition: Total energy expenditure for physiological processes, affecting organismal ecology.
Kleiber's Law: Describes the relationship of metabolic rate (heat produced per day) to body mass, demonstrating a log-log scaling where metabolic rate and body size have a linear relationship.
Surface Area vs. Volume: As organisms grow, their volume increases faster than their surface area, posing challenges for heat dissipation from metabolic processes.
Scaling Expectations: The metabolic rate should scale with body mass (M) tuned down by an exponent of 2/3 to prevent overheating.
Fractal Branching: A better scaling of 3/4 arises from the distribution of materials through bodies, influenced by fractal geometries which enhance the efficiency of nutrient and waste transport.

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Description

Explore the intricacies of photosynthetic pathways, including C4 and CAM processes, and their adaptations to environmental conditions. This quiz delves into how different plant species optimize carbon uptake and water usage. Discover the role of heterotrophy in energy conversion in organisms.