Characteristics Of Living Organisms
Overview
How do you tell something that is alive from something that is not? A rock and a mushroom, a candle flame and a cell: each pair can look similar at a glance, yet only one of each is truly living. Biologists settle the question with a checklist of seven life processes that every living organism, from a single bacterium to a blue whale, carries out.
In this lesson you will learn those seven characteristics and the precise definition of each, captured by the well known memory aid MRS GREN. By the end you will be able to define every process in exam language and decide, with reasons, whether any given thing counts as a living organism.
Objectives
- Describe the characteristics of living organisms by describing: (a) movement as an action by an organism or part of an organism causing a change of position or place (b) respiration as the chemical reactions in cells that break down nutrient molecules and release energy for metabolism (c) sensitivity as the ability to detect and respond to changes in the internal or external environment (d) growth as a permanent increase in size and dry mass (e) reproduction as the processes that make more of the same kind of organism (f) excretion as the removal of the waste products of metabolism and substances in excess of requirements (g) nutrition as the taking in of materials for energy, growth and development
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Lesson Evaluation
Congratulations on completing the lesson on Characteristics Of Living Organisms. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- In the mnemonic MRS GREN, what does the letter N stand for? A. nutrition B. nervousness C. nitrogen D. nutrients Answer: A
- Which process is defined as a permanent increase in size and dry mass? A. respiration B. growth C. excretion D. nutrition Answer: B
- Removal of undigested food from the gut is called: A. excretion B. egestion C. secretion D. respiration Answer: B
- Which characteristic is the ability to detect and respond to changes in the environment? A. movement B. sensitivity C. reproduction D. nutrition Answer: B
- Respiration is best described as: A. breathing air in and out B. chemical reactions in cells that release energy from nutrients C. taking in food D. removing carbon dioxide only Answer: B
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