This course presents the principles of evolution, ecology, and behavior for students beginning their study of biology and of the environment. It discusses major ideas and results in a manner accessible to all Yale College undergraduates. Recent advances have energized these fields with results that have implications well beyond their boundaries: ideas, mechanisms, and processes that should form part of the toolkit of all biologists and educated citizens.
Celebrating Science & Humanity
Darwin Day is a global celebration of science and reason held on or around Feb. 12, the birthday anniversary of evolutionary biologist Charles Darwin.
On this website you can find all sorts of information about Charles Darwin and the International Darwin Day Foundation. If you are hosting a Darwin Day event, you can post information about it on our events listing. You can also locate Darwin Day programs near you by searching our events section.
We also have resources for hosting Darwin Day events, including promotional support and a list of potential Darwin Day presenters.
Click here to read more about the history of the International Darwin Day Foundation.
Darwin Day News
We need you to take action to help us honor Charles Darwin! Click through to learn how you can help.
Life history covers three main classes of traits in organisms: age and size at maturity, number and size of offspring, and lifespan and reproductive investment. Organisms must make tradeoffs among these traits that typically cause them to come to evolutionary equilibrium at intermediate values. Life history traits are evolutionary solutions to the ecological problems of the risk of mortality and the acquisition of food, and they are expressed in reaction norms that determine the particular traits that an organism will exhibit when its genes encounter a specific environment during development.
Sexual Selection is a component of natural selection in which mating success is traded for survival. Natural selection is not necessarily survival of the fittest, but reproduction of the fittest. Sexual dimorphism is a product of sexual selection. In intersexual selection, a sex chooses a mate. In intrasexual selection, individuals of one sex compete among themselves for access to mates. Often honest, costly signals are used to help the sex that chooses make decisions.
Speciation is the process through which species diverge from each other and/or from a common ancestor. There are several definitions of species, most of which focus on reproductive isolation and/or phylogenetic similarities. This can cause some controversy. Speciation can result from geographical separation or ecological specialization. There are stages of speciation in which organisms cluster first into distinct populations before finally becoming different species.
The Tree of Life must be discovered through rigorous analysis. Genetic information is crucial because appearances can be deceiving, and species that look similar can prove to be genetically very dissimilar and not share recent common ancestors. Two criteria, used to determine what the “correct” Tree is, are simplicity and whether the tree maximizes the probability of observing what we actually see.
We can use methods of genetic analysis to connect phylogenic information to geographical histories. Human migration has left genetic traces on every continent, and allows us to trace our roots back to Africa. Molecular genetic methods allow us to determine whether or not trait states were ancestral, which can have profound implications for fundamental biological ideas.
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.
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 fossil record holds a lot of evolutionary information that can…
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…