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"Starting in the Middle", Part I of Darwin's Dangerous Idea, gets its name from a quote by Willard Van Orman Quine: "Analyze theory-building how we will, we all must start in the middle. Our conceptual firsts are middle-sized, middle-distance objects, and our introduction to them and to everything comes midway in the cultural evolution of the ...
In biology, an identification key, taxonomic key, or frequently just key, is a printed or computer-aided device that aids in the identification of biological organisms. Historically, the most common type of identification key is the dichotomous key , a type of single-access key which offers a fixed sequence of identification steps, each with ...
We add another 9 billion tons or so a year, an amount that has been increasing by 6 percent annually. Essentially, we have increased the concentration of carbon dioxide in the air to higher than it has been in the last several million years. [24] Some of this carbon dioxide is being absorbed by our oceans to create carbonic acid.
The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet's obligate anaerobes. Researchers have identified five other major extinction events in Earth's history, with estimated losses below: [11] End Ordovician: 440 million years ago, 86% of all species lost, including graptolites
Edward Hitchcock's fold-out paleontological chart in his 1840 Elementary Geology. Although tree-like diagrams have long been used to organise knowledge, and although branching diagrams known as claves ("keys") were omnipresent in eighteenth-century natural history, it appears that the earliest tree diagram of natural order was the 1801 "Arbre botanique" (Botanical Tree) of the French ...
This was a major advance in the field of biology since little was known about animal structure up to this point compared to plants. From these conclusions about plants and animals, two of the three tenets of cell theory were postulated. 1. All living organisms are composed of one or more cells 2. The cell is the most basic unit of life
The following two examples show how meaning changes subtly depending on whether I or we is used. When using the membership we, the reader or speaker is automatically drawn into the collective, and the change in viewpoint is significant: If I consume too much, I will run out of resources. If we consume too much, we will run out of resources.
In molecular biology, reading frames are defined as spans of DNA sequence between the start and stop codons. Usually, this is considered within a studied region of a prokaryotic DNA sequence, where only one of the six possible reading frames will be "open" (the "reading", however, refers to the RNA produced by transcription of the DNA and its ...