There are seven agreed upon characteristics of life, which can be summed up in the following:
1) Order: All living things demonstrate complex organization, structure, and complexity.
2) Regulation: The environment in which the living thing inhabits may change, but homeostasis still allows the organism to keep a constant inner state.
3) Growth and Development: The ability to pass on DNA and to use that DNA to grow into another organism from birth
4) Energy Processing: Organisms take in some form of energy, and can be processed to fuel the organism's functions
5) Response to the Environment: An organism's ability to react to a change in the environment.
6) Reproduction: Organisms are able to reproduce their own kind
7) Evolutionary Adaptation: An organism's ability to pass on it's genes and utilize them in a way that allows for the greatest evolutionary advantage.
What are the three accepted Domains in Classifying life?
In the art of classifying life, the broadest category we can place an organism in would be a domain, which recently made the cross from two to three.
1) Eukarya: Most of what we see is in this domain. Classified by having a nucleus, as well as other cellular structures.
2) Bacteria: Microscopic, prokaryotic and mostly unicellular.
3) Archaea: Recently discovered, also prokaryotic and for the most part, unicellular.
What is Natural Selection?
Natural selection as a concept isn't too difficult, the basic idea being is a given organism with a desireable trait, perhaps acquired through mutation or breeding, this trait will allot the creature with a greater chance of living, and thus allowing it to have offspring with the same traits. Those offspring then have a better chance of living, thus will reproduce themselves (see where this is going?).
The Facts:
-Science is a part of everyday life, such as in problem solving or testing out a new idea.
-While some organisms may not have all the characteristics of life, that doesn't necessarily mean they're not alive.
-Eukaryotic cells are divided into compartments and consist of many internal organelles and structures such as nuclei.
-DNA is crucial to life, as it not only ensures evolution, but also that lifeforms have a universal genetic structure.
-Earth itself is one giant structure, known as the biosphere, which supports all known life.
Some Key Terms:
-Biology: The scientific study of life
-Biosphere: Consists of all the environments on Earth
-Producers: Provide food for the typical ecosystem
-Consumers: Eats the plants and other animals
-Cell: Basic unit of life
-Genes: Units of inheritance
-Evolution: An explanation for the unity and diversity in life, that all things changed over time
-Natural Selection: A key mechanism for evolution, stating that the organisms with the more desirable traits will pass them on
-Hypothesis: a proposed explanation for a set of observations
-Theory: Supported by a large and growing body of evidence
Diagram:
This is a clear demonstration of the cycle of life from a biological system and the concept of energy transfer.
Summary:
This chapter was very brief, but was a basic overview of systems of life, as well as classification. It touched on the layers of biological study, from the ecosystems to structures on a microscopic level- the study of life is a very broad topic. From there it talks about the classification of life which has three domains (see above) and further sub-branches (Kingdoms, Phylum, Class, Order, Family, Genus and Species).
It then moves on to talk about my personal hero, Charles Darwin, a man of great intelligence who originally came up with the theory of Natural Selection. The idea of Natural Selection is that the ones with the desirable traits will continue to live and have children, thus having offspring with the same traits, and eventually this leads to a change of the species as a whole. Or perhaps creating a new one.
Here is a sped-up version of evolution, courtesy of the Simpsons:
http://www.youtube.com/watch?v=faRlFsYmkeY
P.S. Darwin is my homeboy
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