BILD 3 Unit 2

Describe the prevailing view regarding evolution and species in Europe in the 1800s.

During the 1800s, the prevailing view in Europe was that species were fixed and unchanging, with a belief in a hierarchically arranged scale of life. This perspective was challenged by the emergence of evolutionary theory, particularly through the work of Charles Darwin, who proposed that species evolved over time through natural selection.

Define the hypothesis of gradual and consistent geologic change, name its main

proponent, describe its predictions about the age of the Earth, and discuss the evidence

to support it that Darwin found on his voyage.

theory of uniformitarianism, proposed by Charles Lyell. This hypothesis suggests that the Earth's features were shaped by continuous and gradual processes over long periods. This theory supported Darwin's understanding of deep geological time, allowing for the slow processes of evolution to occur.

Describe the biogeographical patterns Darwin observed on his voyage and explain how

each of them provides support for the theory of evolution.

Darwin observed distinct species on different islands that were similar yet adapted to their unique environments, leading to the concept of adaptive radiation. He also noted the geographical distribution of species, particularly how separate landmasses housed unique species that were closely related. These patterns support evolution by demonstrating how species can diverge and adapt based on their environments over time.

Explain the principle of succession and why it constitutes evidence for descent with modification.

The principle of succession refers to the observation that fossil species in older rock layers are often different from those in newer layers, suggesting a chronological progression of life forms. This pattern supports the theory of descent with modification by indicating that species have evolved over time, with newer species emerging from older ancestral forms.

Describe the process of artificial selection, compare it to natural selection, and explain why it contributed to Darwin’s understanding of evolution.

Artificial selection is the intentional breeding of organisms by humans for desired traits, contrasting with natural selection, where environmental pressures drive survival and reproduction. This process highlighted how selective pressures could lead to significant changes in species over relatively short periods, reinforcing Darwin's ideas about the variability and adaptiveness of traits in evolution.

Give some examples of how organisms have established populations in new habitats via dispersal.

Organisms establish populations in new habitats by dispersing through methods such as wind, water, and animal transport. For example, plant seeds may be carried by the wind to distant locations, while birds can transport seeds in their droppings, leading to the colonization of new areas.

Describe the process of adaptive radiation that led from one mainland species to many

Galapagos finch species with different beaks. Explain how local adaptation can contribute to increased differences between populations.

Adaptive radiation is the process by which a single ancestral species evolves into a variety of forms adapted to different environments. In the case of the Galapagos finches, this led to various species with specialized beak shapes suited for different food sources, illustrating how local adaptations to specific ecological niches can amplify differences between populations.

Describe the two main ideas in Darwin’s Origin of Species.

• Evolution (Descent with Modification): All living species descended from common ancestors, branching out like a great tree of life over long periods of time rather than remaining static.

• Natural Selection: Organisms with random, advantageous physical or behavioral traits are better equipped to survive and reproduce in their environment. Over generations, these favorable traits become more common in the population.