Celebrating Science & Humanity


Portrait By: G. Richmond

 

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 Profile: Dr. Robert Stephens

Dr. Robert Stephens came up with the idea for Darwin Day in 1993 and co-founded the Darwin Day Program. Read his interview with Humanist Network News editor Maggie Ardiente on the early days of Darwin Day.

Lecture 24: Climate and the Distribution of Life on Earth

This lecture provides an overview of the physical aspects of earth

Lecture 25: Interactions with the Physical Environment

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.

Lecture 26: Population Growth: Density Effects

The growth of populations is held in check by several factors. These can include predators, food and other resources, and density. Population density affects growth rate by determining how likely is it that an organism will interact with a member of its own species compared to an organism of a different species. Population growth studies rely on the mathematics of logs and exponents.

Lecture 27: Interspecific Competition

Competition among species, or inter-specific competition, can have an even greater effect on selection than competition within species (intra-specific competition). This is often the case in lower density populations. Different species can have positive, neutral, or negative effects on each other

Lecture 28: Ecological Communities

The idea of ecological communities has changed tremendously over the past 40 years. The classical view stated that there were so many different species because evolution packed them tightly into the available niches. The modern view emphasizes the idea of trophic cascades, or top-down control in food chains. This emphasized the importance of predation in ecology, although it downplayed the significance of food webs, which showed the interrelated nature of ecosystems better than simple food chains.

Lecture 29: Island Biogeography and Invasive Species

Geography is very important in ecology. Two major systems have been designed to model this, island biogeography and metapopulations. The idea of metapopulations is more recent, and has emerged as the dominant theory. Metapopulations are populations in multiple neighboring areas. The population of a species in any individual area may go extinct, but the metapopulation still survives. The theory of metapopulations has gained momentum in recent years because of its applications to epidemiology, the study of diseases.

Lecture 30: Energy and Matter in Ecosystems

The movement of matter and energy around the planet is very important, and its study draws on geology, and meterology in addition to chemistry. Energy tends to flow upwards from plantlike producers to herbivores to carnivores before being decomposed by detritovores and cycling back into energy usable by producers, in addition to the photosynthesis or chemosynthesis used by producers to produce energy. Like energy, compounds vital to life such as carbon, nitrogen, and phosphorous flow around the planet in cycles.

Lecture 31: Why So Many Species? The Factors Affecting Biodiversity

One can look at biodiversity from several perspectives. An ecological point of view tries to determine how necessary diversity is for an ecosystem to function. An economic point of view tries to capture the value of the “services” nature provides for mankind. An evolutionary point of view shows how artificial the human “right” to dominance is. Finally, a personal point of view captures the emotional basis for the values that humanity place on biodiversity.

Lecture 32: Economic Decisions for the Foraging Individual

There are several ways to examine the behaviors of organisms when they forage or hunt for food or mates. These behaviors become more complex in higher organisms, such as primates and whales, which can hunt in groups. Foragers and hunters have been shown to examine the marginal cost and marginal benefit of continuing an action and then adjust their behaviors accordingly. They are also able to handle risk by hoarding resources.

Lecture 33: Evolutionary Game Theory: Fighting and Contests

The economic concept of game theory can be readily applied to evolution and behavior. By analyzing encounters between organisms as a mathematical “game,” important information such as fitness payoffs and the proportions of “strategies” played by each group within a population can be inferred. While oftentimes these games are too simplified to apply directly to actual examples in nature, they are still useful models that help to convey important concepts.