Levels of turkpopmuzigi.comlogical Organization

There is a hierarchy of scale between small and large in living things, which has an organized structure (PageIndex[1]).Atoms are the smallest, most fundamental units of matter.There is a nucleus surrounded by electrons.Atoms combine to form molecules, which are chemical structures made up of two or more atoms joined together by chemical bonds.Plants, animals, and many other types of organisms have organelles, structures created when molecules come together in specific ways.They are the structures that exist within cells and perform specific functions.A cell is a part of every living being, as discussed more fully below.


The cells of multicellular organisms combine to form tissues, which consist of groups of similar cells that operate in the same way.There are organs that are collections of tissues that have the same function.Organs can be found in animals as well as in plants.There are several types of organ systems, each consisting of structurally related organs.In vertebrates for example, the circulatory system transports blood throughout the body and to and from the lungs; it includes organs such as the heart and blood vessels.Each living organism is an individual living being.A forest tree, for instance, is an organism.

Species living in a specific area are collectively defined as a population.A community is a collection of different populations inhabiting one location.Trees, flowers, insects, and other populations in a forest form its community.In other words, the forest is an ecosystem.There are many elements in an ecosystem, including living organisms and non-living components such as the nitrogen in the soil or rainwater. .The sphere includes the lands, the seas, and the atmosphere.

Components of Prokaryotic Cells

A prokaryotic cell is a simple, one-celled (unicellular) organism without a nucleus or other membrane-bound organelle.We will see very shortly how this is different in eukaryotes.A prokaryotic nucleoid is found in the center of the cell, where the DNA is located (Figure (PageIndex{1})).


Animal Cells versus Plant Cells