Every species on earth has an environmental range in which it can live. Usually it flourishes in the central portion of this range. Organisms contain a host of adaptations that allow them to manipulate their environments to remain within their preferred range. Plants and animals differ in the nature of these adaptations, which include the control of water, temperature, pH, and ion concentration.
This lecture provides an overview of the physical aspects of earth’s biomes. Temperature, water, latitude, and altitude all come into play. Regions with similar levels of these climatic features tend to have similar life-forms living there. These same climatic features can also affect weather patterns, which in turn affect life by altering habitats and ecosystems. On a large enough scale, such as El Niño, these weather patterns can affect life all over the earth.
While there are many differences between modern science and philosophy, there are still a number of lessons in modes of thought that scientists can take from philosophy. Scientists’ ideas about the nature of science have evolved over time, leading to new ideas about falsifiability, creativity, revolutions, and the boundaries and limits of what can be accomplished by different types of science.
There is a distinct possibility that humans are currently part way through an evolutionary transition between individuals and groups. The conflict between these two units of selection and levels of organization, between biology and culture, may explain some of the tensions in modern human life. Examples of selfishness and altruism exemplify how these types of selection act on humans.
Midterm Exam 1 covers the first half of the course.
Evolution plays an important though underutilized role in medicine. Evolution guides how our bodies respond to various treatments, how pathogens will respond to treatments, and how pathogens’ responses will change over time. Pathogens oftentimes will evolve to an intermediate level of virulence where they become strong enough to infect a host and reproduce, but not so strong as to kill the host before it can spread the pathogen.
Coevolution happens at many levels, not just the level of species. Organelles such as mitochondria and chloroplasts serve as good intracellular examples. Other living things make up a crucial component of an organism’s environment. Coevolution can occur in helpful ways (symbiosis) and in harmful ways (parasitism). Many factors can influence coevolution, such the frequency and degree of interaction.
The fossil record holds a lot of evolutionary information that can’t be seen on shorter time scales, although the more recent fossil record is more complete. Among other things, the fossil record demonstrates that extinctions can open up ecological space for new speciation and radiation, and that life forms tend to begin small and evolve to be bigger over time.
Geology and climate have shaped the development of life tremendously. This has occurred in the form of processes such as the oxygenation of the atmosphere, mass extinctions, tectonic drift, and disasters such as floods and volcanic eruptions. Life, particularly bacteria, has also been able to impact the geological makeup of the planet through metabolic processes.
The history of life and evolution has been characterized by several key events. These events can be grouped as new hierarchal levels of selection coming into play, as biological units coming together in symbiosis and specialization, or in a number of other ways. Other important events are situations of conflict resolution or information transmission, from the genetic to the cultural level.
