#1: Exchange Between Organisms + Environment

These flashcards cover key concepts regarding the exchange of materials between organisms and their environment, focusing on surface area to volume ratios and adaptations for exchange.

What is the significance of surface area to volume ratio in organisms?

It determines the efficiency of exchange processes; larger organisms need adaptations to increase their surface area to volume ratio for effective material exchange.

What are the two main ways materials are exchanged between organisms and their environment?

Passively (diffusion and osmosis) and actively (active transport requiring metabolic energy).

How do larger organisms increase their surface area to volume ratio?

By evolving flattened shapes or specialized exchange surfaces with large areas, such as lungs in mammals or gills in fish.

What is the relationship between metabolic rate and material exchange in organisms?

Organisms with a high metabolic rate exchange more materials and thus require a larger surface area to volume ratio.

Why is diffusion alone insufficient for larger organisms?

As size increases, volume grows faster than surface area, making diffusion too slow to meet the needs of cells within.

List four materials that need to be exchanged between organisms and their environment.

Respiratory gases (oxygen and carbon dioxide), nutrients (glucose, fatty acids, amino acids, vitamins, minerals), excretory products (urea), and heat.

What characteristics do specialized exchange surfaces possess?

Large surface area relative to volume, very thin structure for short diffusion distances, and selectively permeable membranes.

How is the external environment different from the internal environment of an organism?

The external environment varies significantly from the internal environment where tissue fluid is found surrounding cells.

What is the formula for calculating the surface area to volume ratio of a sphere?

Surface area = 4πr² and Volume = 4/3πr³.

Name a factor that can affect the rate of diffusion of substances into cells.

Concentration gradient, surface area, and thickness of the exchange surface.