Unit 4 Test Review PDF

**Unit 4 Test Review** **Guiding Questions:** - - - - - Behavioral, physical or physiological. An organism would go through a behavioral change by its habits in the way it is for example or hibernating like a bear during a cold season. An organism would go through a physical change by...

**Unit 4 Test Review** **Guiding Questions:** - - - - - Behavioral, physical or physiological. An organism would go through a behavioral change by its habits in the way it is for example or hibernating like a bear during a cold season. An organism would go through a physical change by having physical characteristics to help survive in its environment. For example having thicker skin like a seal for extreme temperatures in water can help it withstand the cold. **Define:** Environment The surrounding in which an organism lives and operates. --------------- --------------------------------------------------------------------------------------------------------------- Adaptations The process of change where an organism becomes better suited to its environment. Behavioral Natural responses unconsciously that organisms have adapted to do in order survive easier in its environment. Physiological Maintain homeostasis for an organism to survive in the environment in which it exists Homeostasis Self balancing process in an organism to maintain stability internally. Xerophytes A plant that doesn\'t require water to maintain itself. What is the difference between physical, behavioral, and physiological adaptations? Give examples. +-----------------------------------------------------------------------+ | Behavioral: Wolves hunting in packs, to make their hunting more | | efficient, and safer as they are wolves to defend themselves if one | | gets hurt. | | | | Homeostasis: A human shivering when it\'s cold outside, so it makes | | our body move and stabilizes the body\'s internal temperature. | | | | Physiological:A skin of snake to camouflage itself from predators and | | prey. | +-----------------------------------------------------------------------+ What is diffusion? --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Diffusion helps the movement of substances in and out of cells. The molecules from high concentration to a low concentration are moving until equilibrium is reached. Even when the equilibrium is reached the molecules are still moving even though they are balanced status. --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- What factors increase the rate of diffusion? +-----------------------------------------------------------------------+ | The factors that increase the rate of diffusion are temperature, | | increasing surface area, decreasing the thickness of the diffusion | | surface, and maintaining a concentration gradient. | | | | The shorter the distance that needs to be traveled the faster the | | diffusion rate. | | | | If the temperature is high there is most likely more movement in the | | molecules so the diffusion rate is increased. | | | | If the solvent is dense it could slow down the diffusion rate. | | | | A substance with less mass will likely have a faster diffusion rate. | | | | In a cell if there is larger surface area buta thin membrane vs a | | smaller surface area but thick membrane the diffusion rate would be | | faster with the larger surface area. This is because a larger surface | | area provides more space for the molecules to pass through the | | membrane any given time. This means that the molecules can diffuse | | simultaneously making the diffusion rate faster. | | | | Concentration gradient: Determines the rate of diffusion. | | | | - - - - | +-----------------------------------------------------------------------+ The adaptation in the figure above is found in larger organisms, not smaller ones such as single-celled amoeba. Why do you think that is? ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Larger organisms such as humans and animals have these adaptations to support their size and body functions that simple diffusion can\'t achieve. Single celled organisms such as amoebas that absorb the nutrients and oxygen in the environment around them don\'t require what large organisms need which is organs and organs systems to transport nutrients efficiently throughout the bodies. Simple diffusiuon wouldnt work in this example because since it is a large organism; a human more cells need oxygen and nutrients meaning it requires diffusion. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- **True or False:** All adaptations are visible *False* The larger the surface area, the faster the rate of diffusion *True* The thicker a surface/membrane is, the longer it takes for diffusion *True* All organisms have specialized structures to aid diffusion *False* Single celled organisms such as amoebas don\'t require diffusion but instead rely on simple diffusion. What is a concentration gradient? ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The concentration gradient is when the particles are moving from a high concentration to a low concentration. The concentration gradient is the one that drives the molecules into areas until the equilibrium is reached. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- What is the surface area to volume ratio and how does it relate to organism size? -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- The surface area to volume ratio is a way to compare the surface area of an object organism compared to its volume. This is something is useful to know as the larger the surface area to volume ratio is the faster diffusion can happen. -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Why do larger organisms need specialized structures? ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Since they can\'t rely on just simple diffusion as smaller structures can, they need to rely on specialized organs and organ systems to provide nutrients and oxygen to their entire bodies. In larger organisms there are more cells meaning that more organs are required to supply oxygen and nutrients into them.The specialized systems help overcome the limitations of diffusion by transporting materials closer to the cells. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Why do cells have to divide as they grow? ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Cells divide because as they grow, their surface area to volume ratio decreases, making it harder for them to exchange nutrients and waste efficiently. A high diffusion ratio to volume is key for nutrients and oxygen to be efficiently transported in and out the cell for its survival. ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------