Evolution – Unit 7 Lecture Notes

Vocabulary flashcards summarizing key people, concepts, and terms related to Darwinian evolution and natural selection.

Evolution

Evolution is how living things change over time, leading to new forms of life. It's a widely accepted idea explaining how all diverse life on Earth has come to be.

Scientific Theory (in biology)

In biology, a scientific theory is a very strong and proven explanation for how nature works. It's built on many facts and observations that have been tested over and over, like the Theory of Evolution.

Charles Darwin

Charles Darwin was a scientist who came up with the main idea of evolution by natural selection. He wrote a famous book called "On the Origin of Species" after traveling the world on the HMS Beagle and studying many years.

HMS Beagle

The HMS Beagle was the ship where Charles Darwin worked as a naturalist during his five-year journey around the world (1831–1836). His discoveries on this trip, especially in the Galápagos Islands, were key to him developing his theory of evolution.

On the Origin of Species

This is Charles Darwin's very important book, published in 1859. Its full name is "On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life". In it, he shared all his evidence for evolution and explained how natural selection makes it happen.

Natural Selection

Natural selection is a main way evolution happens. It's when living things with helpful traits for their environment are more likely to survive, reproduce, and pass those traits to their children. Over many generations, these helpful traits become more common in the group, changing it over time.

Fitness

In evolution, fitness means how well an individual organism can survive and have babies in its environment, passing its genes to the next generation. It's about how many successful offspring an organism produces, not how strong it is.

Adaptation

An adaptation is any trait (like a body part, how it works, or a behavior) that an organism inherits and that helps it survive and reproduce better in its environment. Adaptations make an organism a better fit for where it lives.

Struggle for Existence

The Struggle for Existence is a key idea in Darwin's theory. It refers to the constant competition among living things for limited resources like food, water, space, and mates. This competition decides which individuals survive and reproduce.

Overproduction

This is when organisms produce more offspring than the environment can support. Because resources are limited, this overproduction leads to competition, meaning only some of the offspring will survive to have their own babies. Thomas Malthus's ideas about population growth influenced this concept.

Variation

Variation means the natural differences found among individuals within the same group of living things. These differences (in genes, body, or behavior) are essential for evolution because they give natural selection something to work with; some variations will be more helpful for survival.

Survival of the Fittest

This phrase, used by Charles Darwin, means that organisms best suited to their environment (the 'fittest') are the ones most likely to survive and pass on their traits. It describes the result of natural selection over time.

Descent with Modification

Descent with Modification was Darwin's way of explaining evolution. It means all living things are connected to a common ancestor, and over long periods, they gradually change and adapt to different places. This is why we see so many different kinds of life today, like the finches on the Galápagos Islands with their different beaks.

Common Descent

This is the idea that all living things on Earth, from tiny bacteria to large animals, came from one single, shared ancestor if you go back far enough in time.

LUCA (Last Universal Common Ancestor)

LUCA stands for Last Universal Common Ancestor. It's the organism (or group of organisms) from which all life we know today has descended. LUCA isn't the 'first' life, but it's the point in history where all life's family trees connect.

Artificial Selection

Artificial selection is when humans intentionally choose which plants or animals to breed to get specific traits they want. For example, breeding dogs for certain looks or crops for bigger yields. Darwin used this idea to help explain how natural selection works in nature.

Jean Baptiste Lamarck

Jean Baptiste Lamarck was an early thinker about evolution. He had a theory, now known to be incorrect, called the inheritance of acquired characteristics. He thought that traits an animal gained during its life (like a stronger arm from using it) could be passed on to its children.

Inheritance of Acquired Characteristics

This was Lamarck's mistaken idea that traits an organism develops during its life (like strong muscles from exercise) can be passed down to its children. We now know that only traits written in an organism's genes can be passed on.

Thomas Malthus

Thomas Malthus was an economist whose ideas greatly influenced Charles Darwin. Malthus argued that human populations grow faster than food supplies, leading to struggle and scarcity. This made Darwin think about how competition for resources drives survival and reproduction in nature.

James Hutton

James Hutton was a geologist who said that Earth was shaped by very slow forces like erosion and volcanoes over incredibly long periods, not by sudden big events. His ideas suggested Earth was much older than people thought, which helped Darwin understand how slow changes could lead to evolution.

Charles Lyell

Charles Lyell was a geologist who wrote a famous book called "Principles of Geology". He strongly supported the idea of uniformitarianism, which means the same processes we see shaping Earth today have been doing so for a very long time. His work convinced Darwin that Earth was extremely old, which was key for his theory of gradual evolution.

Uniformitarianism

Uniformitarianism is a core idea in geology. It states that the natural laws and processes we see happening on Earth today (like erosion, volcanoes, and earthquakes) have always been working in the same way and at similar speeds throughout Earth's long history. This idea of slow, continuous change deeply influenced Darwin's view of evolution.

Alfred Russel Wallace

Alfred Russel Wallace was a naturalist who, entirely on his own, came up with the same idea of natural selection as Charles Darwin. When he sent his findings to Darwin, it pushed Darwin to finally publish his own theory in "On the Origin of Species". Wallace also largely developed the study of biogeography.

Biogeography

Biogeography is the study of where different plants and animals live around the world. It looks at why certain species are found in certain places. Alfred Russel Wallace was a pioneer in this field, and his observations confirmed how species adapt to their local areas, supporting the idea of evolution.

Speciation

Speciation is the process where a new species forms from an existing one. This often happens when groups of organisms become separated and then change over time to fit different environments, eventually becoming so different they can no longer reproduce with each other. A great example is the different finches and tortoises on the Galápagos Islands.

Niche

A niche is an organism's unique job or role in its environment. It includes everything about how an organism lives, what it eats, where it lives, and how it interacts with other species. When organisms move into different niches, it drives adaptation and the formation of new species over time.