Level | Examples | Special consideration |
Ecosystem | Rain forest, desert, fresh water lake, digestive tract of animal for bacteria | Includes all living organisms and non living matter such as air, water and minerals |
Community | All species in an ecosystem | Only includes living things from bacteria, to fungi, to plant to animal |
Population | All individuals of a single species | Includes only individuals from a specific species such as a plant, an animal, a bacterial colony |
Organism | One single individual | Serves as a representative of the species and describes overall form and function of an organism |
Organ system | A specialized functional system of an organism | The nervous system or immune system of an animal |
Organ | A specialized structural system of an organism | The brain or the thymus of an animal |
Tissue | A specialized substructure of an organ | The nervous tissue and epithelial tissue are both part of the brain |
Cell | A single cell | A neuron, a skin cell, a root cell, bacteria, yeast, paramecium |
Molecule | A single large or small molecule such as a protein, DNA, sugar or fatty acid | Molecules are the smallest part of biological systems; they can be studied for their chemical, physical properties, but are of particular interest for their usefulness in biological systems. |
Monday, October 5, 2009
Bioethics Part 4: The Hierarchy of Life
In a post below we considered one commonly referenced hierarchy of being. Now let's examine and discuss this one. Note that the chart below doesn't classify "DNA (a molecule)" or "cells" as people. People are "organsims."
Excerpt:
The structure of living organisms including those of entire populations and ecosystems is organized in a hierarchical fashion that allows a systematic exploration of the question ‘What is life?’. In the biological sciences, the following structural levels are recognized:
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2 comments:
Thanks for the science content. Without getting into the technicals, I would caveat that you have to look at higher plants and animals to be sure to see every level.
To state unambiguously that science proves that life begins at conception can be described as nothing other than a deliberate lie.
This hierarchy is based on empirical observations and the contributions of many scientists over time. There conclusions were subject to review by their peers. It's a product of enlightenment.
The biases of the previous hierarchy are obvious. It's from a specific culture. Everything is based on its usefulness to man, and it regards some people as more special than others.
In other news, one of the scientists Bush kicked off his bioethics panel just one the Nobel prize. Among other things, telomeres relate to aging, cancer, and were used to definitively show evolutionary changes between humans and other primates.
"There conclusions were subject to review by their peers. It's a product of enlightenment."
Unlike my spelling.
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