BIOLOGY NOW WITH PHYSIOLOGY - CHAPTER 11: Evidence for Evolution

Flashcards covering key definitions, types of evidence, and examples related to the topic of evolution, including natural and artificial selection, fossils, homologous and vestigial traits, DNA, biogeography, and embryonic development.

What is evolution?

A change in the inherited characteristics of a group of organisms over generations.

Do individuals or populations evolve?

Populations evolve; individuals do not.

What is artificial selection?

Artificial selection is brought about by selective breeding, where humans allow only individuals with certain inherited characteristics to mate.

How does selective breeding lead to artificial selection?

Selective breeding involves humans choosing individuals with desired inherited characteristics to mate, which over generations leads to populations with specific traits, a process called artificial selection.

Define natural selection.

Natural selection is the process by which individuals with advantageous inherited characteristics for a particular environment survive and reproduce at a higher rate than individuals with other, less useful characteristics.

In natural selection, who or what 'chooses' the winners?

The environment 'chooses' the winners.

What is an adaptation in an evolutionary context?

An adaptation is an evolutionary process by which a population becomes better matched to its environment over time through natural selection.

List the six types of evidence for evolution.

1. Direct observation of evolution through artificial selection, 2. Fossil evidence, 3. Shared characteristics among living organisms, 4. Similarities and differences in DNA, 5. Biogeographic evidence, 6. Common patterns of embryo development.

What are fossils?

The mineralized remains or impressions of formerly living organisms.

How does the fossil record provide evidence in support of evolution?

The fossil record enables biologists to reconstruct life's history on Earth, showing the evolution of species over time and providing examples of how new groups of organisms arose from previously existing ones.

How does the depth at which a fossil is found relate to its age?

Older fossils are typically found in deeper, older rock layers.

What is a transitional fossil?

Transitional fossils are evidence of species with similarities to both the ancestral group and the descendant species, illustrating evolutionary intermediate steps.

Give an example of a sequence of whale ancestors that illustrates transitional fossils.

Pakicetus (land, waded), Ambulocetus (semiaquatic, crocodile-like), Rodhocetus (streamlined, flipper-like limbs), and Dorudon (fully aquatic) are transitional fossils illustrating whale evolution. Indohyus is an extinct whale 'cousin'.

What peculiar feature of Indohyus suggested its close relationship to whales?

The ear bone of Indohyus looks more like a whale ear bone than that of any other land mammal.

What adaptation in Indohyus’s leg bones suggested a water-dwelling lifestyle?

Indohyus had thick leg bones, a feature seen in modern shallow water animals, which helps them prevent floating and allows them to dive quickly.

What is a common ancestor?

A single organism from which many species have evolved.

What does it mean for a group of organisms to share common descent?

Common descent means that a group of organisms share a common ancestor.

What are homologous traits, and how do they support the theory of common descent?

Homologous traits are similar features in species that have common descent (inherited from a common ancestor), even if these features have evolved to look different over time. Their underlying similarity points to a shared evolutionary origin.

What are vestigial traits, and how do they support the theory of common descent?

Vestigial traits are features inherited from a common ancestor but are no longer used or appear as reduced/degenerated parts with no apparent function (e.g., vestiges of hind limbs in whales). Their presence suggests a common ancestry with organisms where the trait was functional.

Are vestigial structures also homologous structures? Explain.

Yes, vestigial structures are a type of homologous structure because they are inherited from a common ancestor, even if their function has been lost or reduced.

How does the universal use of DNA and a common genetic code across all living organisms support the theory of common ancestry?

All living organisms on Earth, from bacteria to redwood trees and humans, use DNA and decipher it using the same genetic code, which is strong evidence that all living things evolved from a common ancestor.

What does DNA sequence similarity indicate about species?

DNA sequence similarity is a measure of how closely related two DNA molecules are to each other, which in turn indicates the evolutionary relatedness between species.

How do similarities and differences in DNA sequences support evolution?

Increased similarity in the DNA sequences of genes between more closely related organisms—and decreased similarity between less closely related organisms—provides strong evidence for a shared evolutionary history and subsequent divergence.

What is continental drift (or plate tectonics), and how has it influenced the distribution of species?

Continental drift is the slow movement of Earth's massive tectonic plates. This process has separated landmasses over millions of years, leading to the unique geographic distribution of species and their fossils across different continents.

What was Pangaea, and when did it begin to split up?

Pangaea was a single giant continent formed by all of Earth's landmasses approximately 250 million years ago (mya). It began to split up around 200 mya.

What does the biogeography of a species refer to?

The biogeography of a species refers to the geographic locations where its fossils will be found, and where the species currently lives.

How does biogeographic evidence support evolution?

The distribution of species and their fossils across continents reflects their evolutionary past, showing how species diverged as landmasses separated. For example, ancestral fossils of a species found globally from the Pangaea era, even if the living species is now restricted to a single continent.

How do similarities in embryonic development among species provide evidence for evolution?

Embryonic development can mirror early developmental stages of ancestral forms. Shared patterns among diverse species (such as gill slits and tails in early fish, reptile, bird, and human embryos) result from descent from a common ancestor.

Are similar structures among species during early embryonic development considered homologous structures? Explain.

Yes, similar structures during early embryonic development are homologous because they are inherited from a common ancestor that possessed these fundamental features.

Compare and contrast artificial selection and natural selection, naming two similarities and explaining their main difference.

Similarities: Both result in changes in the inherited characteristics of a population over generations, and both lead to beneficial traits becoming more common in a population. Difference: In artificial selection, humans actively select which individuals reproduce based on desired traits, whereas in natural selection, the environment itself 'chooses' which individuals survive and reproduce more successfully based on their adaptable traits.

Name four common characteristics shared by all mammals.

Mammals maintain a stable body temperature, have backbones, breathe air, and nurse their young from mammary glands.

Which example illustrates evolution by natural selection: a) adapting to cold weather, b) a gene mutation for increased blood oxygen in high-altitude people, or c) improving running distance through training?

b) Many people living in the high-altitude, oxygen-poor region of Tibet have a gene mutation that increases their blood oxygen supply.

Which of the following is NOT an example of evolution by natural selection: a) peppered moths changing color due to industrial soot, b) MRSA (methicillin-resistant S. aureus) infection, c) developing large, round tomatoes, or d) herbicide-resistant morning glories?

c) The agricultural industry has developed varieties of tomatoes with characteristics, such as large size, uniform red coloration, and roundness (this is an example of artificial selection).

Birds and insects both have wings for flying. What type of trait are these wings in this example?

An adaptive trait. (Although analogous, the question's focus is on function, making 'adaptive' the best fit among the choices).

If a homologous trait is no longer useful in a specific organism, what term is used scientifically to describe it?

Vestigial.