Early Study of Evolution

Early Study of Evolution

Middle School

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Learning Objectives

• Define variation and adaptation and their role in how species change over time.

• Explain how genetic variation helps a population survive and reproduce in its environment.

• Describe natural selection, where helpful traits become more common over many generations.

• Explain the difference between the scientific ideas of Lamarck and Darwin.

• Describe how fossil evidence supports the modern theory of evolution.

Key Vocabulary

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Evolution

Evolution is the process of change in species over very long periods of time.

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Variation

Variation refers to the natural differences that exist between individuals that belong to the same species.

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Genetic Variation

Genetic variation describes the differences in genes found among individuals within a single population of organisms.

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Adaptation

An adaptation is an inherited trait or special characteristic that helps an organism survive and reproduce.

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Natural Selection

Natural selection is the process where organisms with advantageous traits are more likely to survive.

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Advantageous Trait

An advantageous trait is a characteristic that increases an organism's chances of survival and reproduction.

Key Vocabulary

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Fossil

The preserved remains or traces of an organism that lived in the distant past.

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Population

A group of organisms of the same species that live together in the same area.

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Inheritance

The process by which genetic information and traits are passed from parents to their offspring.

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Scientific Theory

A well-tested explanation for a wide range of observations and confirmed through experimental results.

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Early Ideas and Classification

Carolus Linnaeus

• He developed the first scientific system for classifying organisms based on their shared characteristics.

• His work helped to organize and describe the vast diversity of life found on Earth.

• However, his system did not offer an explanation for how this diversity came to be.

Jean-Baptiste Lamarck

• He proposed that organisms could acquire traits through the use or disuse of body parts.

• Lamarck suggested these acquired traits could then be passed on to their future offspring.

• While incorrect, he introduced the key idea that species can change gradually over many generations.

Multiple Choice

What was the primary goal of the classification system created by Carolus Linnaeus?

• To organize and describe the diversity of life based on shared features.

• To explain how organisms could acquire new traits during their lifetime.

• To prove that all species have remained unchanged since their creation.

• To determine the age of different organisms found on Earth.

Multiple Choice

What important idea did Jean-Baptiste Lamarck introduce that was not addressed by Carolus Linnaeus's system?

• A method for organizing organisms into different groups.

• An explanation for how species might change over many generations.

• The concept that organisms share certain characteristics.

• A system for giving every organism a unique scientific name.

Multiple Choice

A blacksmith develops strong arm muscles from years of hammering metal. According to Jean-Baptiste Lamarck's theory of acquired traits, what would be expected in his children?

• They would be born with stronger than average arm muscles.

• They would have no change in their muscles compared to other children.

• They would need to become blacksmiths to develop strong muscles.

• They would be skilled at hammering without needing to learn.

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Evidence from Rocks and Fossils

Layers of Rock

• Geologist Charles Lyell studied the Earth’s naturally formed layers of rock and the fossils within them.

• He concluded that the Earth's geological features changed slowly and gradually over a very long time.

• His work suggested that the Earth was millions of years old, providing the necessary timeline for evolution.

Evidence of Extinction

• Mary Anning was a fossil collector who discovered and reconstructed the bodies of many ancient animals.

• Her work provided crucial evidence that some animal species from the past were now completely extinct.

• This proved that life on Earth had changed significantly, supporting the theory of evolution.

Multiple Choice

What major scientific theory is supported by evidence from rock layers and the discovery of extinct species in fossils?

• The theory of evolution

• The theory of plate tectonics

• The law of universal gravitation

• The theory of relativity

Multiple Choice

What was the primary significance of Charles Lyell's conclusion that the Earth's geological features changed slowly over a very long time?

• It provided the vast timeline necessary for the slow process of evolution to occur.

• It proved that all fossils found in rock layers are from extinct species.

• It showed that volcanic eruptions were the main cause of geological change.

• It helped Mary Anning locate fossils more easily.

Multiple Choice

A scientist discovers a fossil of an unknown, extinct sea creature deep within the Earth's oldest rock layers. What is the most logical conclusion the scientist can draw from this discovery?

• Life on Earth has changed over a very long period, as shown by ancient, extinct species.

• This creature must have been one of the last species to evolve.

• The Earth's geological features must have formed very rapidly.

• This discovery proves that all modern animals evolved from this one creature.

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Darwin's Journey of Discovery

• Charles Darwin was a naturalist on a five-year voyage on the HMS Beagle.

• He observed the incredible diversity of life around the world.

• He found giant Glyptodon fossils that resembled smaller, modern armadillos.

• Darwin wondered if armadillos evolved from giant Glyptodons over long periods.

Multiple Choice

What was Charles Darwin's key observation about the fossils he found in South America?

• He discovered that armadillos were the largest animals in South America.

• He found fossils of animals that were completely unrelated to any living species.

• He observed that fossils of giant Glyptodons looked similar to modern armadillos.

• He proved that Glyptodons and armadillos were the exact same species.

Multiple Choice

Why was the similarity between Glyptodon fossils and living armadillos significant to Darwin?

• It proved that all ancient animals were much larger than modern animals.

• It suggested a possible evolutionary link between the ancient and modern animals.

• It showed that the environment in South America had not changed over time.

• It indicated that Glyptodons and armadillos competed for the same food.

Multiple Choice

What broader conclusion about life on Earth is supported by Darwin's findings with Glyptodons and armadillos?

• Living organisms may have descended from extinct species that once lived in the same area.

• Animals that live in the same area always evolve to look identical.

• Fossils can only be used to understand the size of ancient animals, not their relationships.

• Evolution only happens in species that live in South America.

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Evidence from the Galápagos Islands

• Organisms on the Galápagos Islands differed from those on mainland South America.

• This led Darwin to believe that species can change over time.

• He observed different finch species that came from one common ancestor species.

• Their different beak shapes are adaptations for eating specific types of food.

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Multiple Choice

What important idea did Darwin develop after observing the organisms on the Galápagos Islands?

• That species can change over time

• That all birds on the islands were identical

• That organisms on islands and the mainland are the same

• That finch beaks are all shaped the same

Multiple Choice

What is the relationship between the different beak shapes of the Galápagos finches and their environment?

• They are adaptations for eating different types of food.

• They are used to attract different mates.

• They are the result of different weather patterns.

• They are for building different kinds of nests.

Multiple Choice

Based on the evidence, what is the best explanation for why one common ancestor finch species evolved into many different species on the Galápagos Islands?

• The variety of available food sources on the islands supported the evolution of different beak shapes.

• The original ancestor finch was able to fly between the islands and the mainland.

• The finches on the islands had no predators, so they could change without risk.

• The mainland did not have enough food, so the finches had to leave.

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Genetic Variation

• Genetic variation is the diversity of inherited traits due to different genes.

• Variation is necessary for populations to adapt to environmental changes.

• High variation increases a population's chance of surviving environmental changes.

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Multiple Choice

Which statement best defines genetic variation?

• The traits an organism acquires during its lifetime.

• The process of a population moving to a new area.

• The way all members of a population look identical.

• The diversity of inherited traits within a population.

Multiple Choice

What is the main reason why genetic variation is necessary for a population?

• It prevents any changes from occurring in a population.

• It makes all individuals in a population identical.

• It allows a population to adapt to environmental changes.

• It guarantees that the environment will remain stable.

Multiple Choice

If a population has high genetic variation, what is the most likely outcome if its environment changes suddenly?

• The population is more likely to survive the environmental change.

• All individuals in the population will remain exactly the same.

• The population will stop having any genetic differences.

• The population will become less adapted to the environment.

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Natural Selection: The Mechanism of Evolution

• Natural selection is the process that drives evolution in a population over time.

• Some genetic variations give organisms an advantageous trait, helping them survive and reproduce.

• Organisms with these helpful traits are more likely to reproduce and pass them on.

• Disadvantageous traits decrease survival chances and become less common over many generations.

Multiple Choice

What is natural selection?

• The process that drives the evolution of species.

• A process where an individual organism changes its traits to suit an environment.

• The way organisms choose their partners for reproduction.

• A method for classifying different types of animals.

Multiple Choice

What happens to advantageous traits within a population over many generations?

• They are passed to offspring and become more common over time.

• They cause an organism to have fewer offspring.

• They disappear completely in the next generation.

• They have no effect on the survival of the species.

Multiple Choice

In a population of giraffes, some have slightly longer necks than others. If the main food source becomes leaves on taller trees, what would be the most likely result for the population over time?

• The trait for long necks would become more common in the population.

• The giraffes would all learn to stretch their necks longer in their lifetime.

• The trait for short necks would become more common in the population.

• The population of giraffes would immediately stop evolving.

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From Hypothesis to Scientific Theory

Hypothesis

• A hypothesis is a proposed explanation for an observation that can be tested through experimentation.

• It is an educated guess that has not yet been supported by a lot of evidence.

• Darwin hypothesized that species adapt to new environmental conditions over many generations.

Scientific Theory

• A scientific theory is a well-tested explanation for a wide range of observations and evidence.

• It is repeatedly confirmed through many experiments and is widely accepted as scientifically true.

• Darwin's idea became the theory of evolution, explaining how and why life on Earth changes.

Multiple Choice

What is a hypothesis?

• A proposed explanation for an observation that can be tested.

• A well-tested explanation for a wide range of observations.

• A scientific fact that has been proven to be true without doubt.

• An observation that is difficult to understand or explain.

Multiple Choice

What is the primary difference between a scientific theory and a hypothesis?

• A theory is a well-tested explanation, while a hypothesis is a proposed explanation that has not yet been widely confirmed.

• A hypothesis is a proven fact, while a theory is just an educated guess.

• A theory is used for a single experiment, while a hypothesis explains a wide range of observations.

• A hypothesis is a well-supported idea, while a theory is a simple observation.

Multiple Choice

Based on the relationship between a hypothesis and a theory, what must have happened for Darwin's initial hypothesis to become the theory of evolution?

• His proposed explanation was repeatedly tested and confirmed with a wide range of evidence.

• His hypothesis was a very popular and widely discussed educated guess.

• His idea was too complicated to be tested with a single experiment.

• His observation was accepted as true without needing any further evidence.

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Common Misconceptions

Misconception	Correction
Traits acquired during a lifetime are inherited.	Only genetic traits stored in DNA are passed to offspring.
Evolution is 'just a theory' and not a fact.	A scientific theory is a well-supported explanation based on evidence.
Individual organisms can evolve during their lifetime.	Populations evolve over generations, not individuals.
Organisms choose to adapt when they need to.	Adaptation occurs by chance through natural selection, not by choice.

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Summary

• Early scientists and Charles Darwin’s observations provided key evidence for the theory of evolution.

• Genetic variation provides the essential raw material for natural selection to act upon.

• Natural selection is the mechanism driving evolution by favoring advantageous genetic traits.

• This process leads to adaptation, explaining the diversity of life on Earth.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

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