organism
Definition
An organism is a biological entity that is capable of independent growth, reproduction, functional activity, and continual change through metabolism. Organisms are classified into three domains: Bacteria, Archaea, and Eukarya.
Bacteria are the simplest organisms. They are single-celled and have no nucleus. Archaea are also single-celled, but they have a different type of cell structure than bacteria. Eukarya are the most complex organisms. They have cells with a nucleus and other specialised structures.
All organisms share certain characteristics. They are made up of cells, they use energy, they reproduce, they grow, and they respond to their environment.
How can the word be used?
Cells are the basic unit of life.
Different forms of the word
Noun: A living thing that is made up of cells and that can reproduce.
Adjective: Relating to or characteristic of organisms.
Etymology
The word "organism" comes from the Greek word "organon", which means "tool" or "instrument". It was first used in English in the 17th century.
The word "organism" originally referred to a living thing that is made up of different parts that work together. However, it has since come to be used to refer to any system that is made up of different parts that work together, such as a machine or a society.
Question
What is an organism?
AQA Science Exam Question and Answer
Question:
Describe the process of adaptation in organisms and how it contributes to their survival in changing environments. Support your explanation with a specific example of an adaptation and its benefits.
Answer:
Adaptation is a biological process where organisms undergo changes over generations to better suit their environment and improve their chances of survival and reproduction. This phenomenon is essential for the long-term persistence of species in changing conditions. An example of adaptation can be seen in the giraffe's neck length.
In areas with tall trees, giraffes with slightly longer necks had an advantage in accessing food, as they could reach leaves that were out of reach for shorter-necked giraffes. Over generations, this selective advantage led to the gradual evolution of giraffes with longer necks. This adaptation increased their access to food resources, enhancing their chances of survival and reproduction.
Adaptations can also involve various aspects of an organism's physiology, behaviour, or morphology. For instance, the Arctic fox's white fur coat during winter helps it blend into the snowy environment, providing camouflage while hunting. These adaptations allow organisms to exploit specific niches, respond to environmental changes, and successfully compete for resources.
In summary, adaptation is a dynamic process that enables organisms to adjust to their surroundings and optimise their survival. Through natural selection, advantageous traits become more prevalent in populations, enhancing their fitness in changing environments.