Coping with Environmental Variation: Energy

This set of flashcards covers key concepts regarding energy acquisition in autotrophs and heterotrophs, photosynthesis processes, adaptations to environmental changes, and the ecological significance of various plant and animal strategies.

What are autotrophs?

Organisms that assimilate radiant energy from sunlight or from inorganic compounds to convert energy into chemical energy stored in organic molecules.

How do heterotrophs obtain energy?

They obtain energy by consuming organic compounds from other organisms.

What is the main difference between holoparasites and hemiparasites?

Holoparasites have no photosynthetic pigments and rely entirely on other plants, while hemiparasites can photosynthesize but still obtain nutrients from a host.

What is chemosynthesis?

A process where energy from inorganic compounds is used to produce carbohydrates, important in certain ecosystems.

Which organisms primarily perform photosynthesis?

Some archaea, bacteria, protists, and most algae and plants.

What are the two major steps of photosynthesis?

1. Light reaction: harvesting light to split water and make ATP and NADPH. 2. Dark reaction: fixing CO2 in the Calvin cycle to synthesize carbohydrates.

What is the light compensation point?

The point at which CO2 uptake is balanced by CO2 loss due to respiration.

What happens to stomates during low water availability?

They close, which restricts CO2 uptake.

How does nitrogen content in leaves affect photosynthesis?

Higher nitrogen levels are correlated with higher photosynthetic rates due to their association with photosynthetic enzymes.

What is photorespiration?

A process where Rubisco catalyzes a reaction with O2, breaking down carbon compounds and releasing CO2.

What is one proposed benefit of photorespiration?

It may protect plants from damage under high light levels.

What plants use the C4 photosynthetic pathway?

Many grass species including corn, sugarcane, and sorghum.

What distinguishes the C4 pathway from the C3 pathway?

C4 pathway involves CO2 uptake and the Calvin cycle occurring in different parts of the leaf, reducing photorespiration.

What is Crassulacean acid metabolism (CAM)?

A process where CO2 uptake and the Calvin cycle are separated temporally, allowing stomates to open at night.

Why do CAM plants have thick, fleshy leaves?

To minimize water loss in arid environments.

What is one strategy of heterotrophs in obtaining energy?

Feeding strategies vary; some invest little energy for low-energy food, while predators invest significant energy for high-energy meals.

What adaptations do multicellular animals have for digestion?

Specialized tissues and organs for absorption, digestion, transport, and excretion.

How do migrating warblers adapt their diet?

They consume different diets in various parts of their ranges, increasing fat absorption efficiency with high fat diets.

What tool usage has been observed in chimpanzees?

They have been known to make tools since the 1920s for access to food.

What is a unique tool-making behavior observed in crows?

Crows on South Pacific islands use tools to extract insects from decomposing trees.

What information can isotopic composition provide about diets?

It can be used to infer the diets of organisms based on the isotopic signatures of their food sources.

Why might tool making have energetic costs?

It requires energy to produce tools, which may offset the benefits of easier access to high-energy foods.

What does the efficiency of fat absorption indicate in migrating warblers?

It suggests that they adapt their feeding strategies based on the energy content of their diet.

What role do nutrients play in photosynthesis?

They affect the efficiency of photosynthesis, particularly nitrogen, which is vital for many photosynthetic enzymes.

How do herbivorous primates' digestive systems compare to omnivorous humans?

Herbivorous primates tend to have longer digestive tracts adapted to their diet.

What are the implications of climatic patterns on C4 plant distribution?

Climatic patterns should predict regions where C4 plants dominate based on their photosynthetic efficiency in high temperatures.