Evolution Flashcards
What is evolution?
A process that results in changes in the genetic material of a population over time.
Who is Charles Darwin?
Charles Darwin was a British naturalist who developed the theory of evolution by natural selection. His work explained how species change over time through a process where the best-adapted individuals survive and reproduce. His famous book, On the Origin of Species (1859), revolutionized our understanding of biology and life on earth.
Darwin’s journey on HMS Beagle and how he came to his conclusion.
Charles Darwin traveled on the HMS Beagle from 1831 to 1836, exploring places like South America, the Galápagos Islands, and Australia. He observed plants, animals, and fossils, noting how species varied between environments. In the Galápagos, he noticed differences in finches’ beak shapes depending on their diets. This led him to realize that species adapt to their environments over time through a process he later called natural selection, forming the basis of his theory of evolution.
Georges Cuvier: fossils and catastrophism.
Studied fossils and proposed that species went extinct due to sudden, catastrophic events. This showed Darwin that life changes over time and species are not permanent.
James Hutton: geologic forces.
Suggested that Earth’s features formed gradually over long periods through slow processes like erosion. This gave Darwin the idea that changes in nature could also happen slowly over time.
Charles Lyell: uniformitarianism.
Built on Hutton’s ideas, arguing that the same natural processes shaping Earth today worked in the past. This helped Darwin see that slow, consistent changes could shape life as well.
Jean-Baptiste: theory of acquired characteristics.
Believed organisms could pass on traits they developed during their lifetime. Although this was incorrect, it got Darwin thinking about how traits are inherited and change over time.
Thomas Malthus: human population growth.
Wrote about how limited resources lead to competition among humans. This inspired Darwin to see how competition in nature could lead to survival of the fittest, key to natural selection.
Descent with modification.
That all living things share a common ancestor, but over time, species change and adapt to their environments. These changes, or modifications, are passed down through generations, leading to the diversity of life we see today.
Selective breeding (artificial selection).
When humans choose specific plants or animals with desired traits to breed, their offspring inherit those traits. For example, farmers breed cows that produce more milk or dogs with certain looks or behaviors. This process shows how traits can change over generations, similar to natural selection.
8 concepts of natural selection.
Organisms produce like organisms. There is stability in the process of reproduction.
Individuals in a species have differences in traits (like size or color). Which is known as variation.
Organisms compete for limited resources like food, water, and shelter.
More offspring are born than can survive.
Which individuals will survive and reproduce and which will not is determined by how well suited an organism is to its environment.
Some traits give individuals an advantage in surviving and reproducing.
Individuals with characteristics that are not well suited to their environment either die or leave few offspring.
Individuals with the best traits for their environment are more likely to survive and reproduce.
The fossil record.
Fossils show a timeline of past life and how species have changed over time, with older fossils being more primitive and newer ones more complex.
Biogeography.
The study of where species live around the world. Similar species found in different places suggest they share a common ancestor but adapted to different environments.
Homologous structures.
Similar body parts in different species (like wings in bats and arms in humans) that have a common origin, showing they evolved from a common ancestor.
Embryology.
The study of embryos shows that many different species look similar in early development, suggesting they share common ancestors.
Biological molecules.
Similarities in DNA, proteins, and other molecules across species show they are related and evolved from a common ancestor.
What is LUCA?
Last Universal Common Ancestor, which is the most recent common ancestor of all life on Earth. It is the organism from which all living things today are descended.
How does this organism lead to all life on earth today?
This organism had basic life functions like DNA, proteins, and a way to make energy, which are found in all living things today. Over time, its descendants evolved into the wide variety of life forms we see now, including plants, animals, fungi, and bacteria.
Examples of evolution in progress.
Peppered Moths: In England, during the Industrial Revolution, dark-colored moths became more common because they were better camouflaged against pollution-darkened trees, while light-colored moths were easier for predators to spot.
Darwin’s Finches: On the Galápagos Islands, finches’ beak shapes evolved based on the type of food available. Some birds developed larger beaks to crack hard seeds, while others had smaller beaks for eating insects.
Extinctions.
When species die out, it can open up ecological spaces for new species to evolve and fill those roles.
Adaptive radiation.
A single species evolves into many different forms to adapt to different environments. For example, Darwin’s finches evolved different beak shapes to feed on different food sources in the Galápagos Islands.
Convergent evolution.
Unrelated species evolve similar traits because they face similar environmental challenges. For example, the wings of birds and bats look similar but evolved independently.
Divergent evolution.
A single species evolves into different species due to different environments or selective pressures. For example, wolves evolving into various dog breeds.
Coevolution.
Two species evolve in response to each other. For example, flowering plants and their pollinators, like bees, evolve together to benefit each other.
Punctuated equilibrium.
Evolution happens in rapid bursts, followed by long periods of little change. Fossil records show species changing suddenly in some periods, then remaining stable for long times.
