Evolution, Bacteria, Archaea, and Eukaryotes
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Based on the concept of molecular homology, which of the following comparisons would likely show the highest percentage of identical amino acids?

  • Yeast protein kinase vs. human p53 protein
  • Human hemoglobin vs. gorilla hemoglobin (correct)
  • Human collagen vs. chimpanzee hemoglobin
  • Chicken hemoglobin vs. human p53 protein

The distribution of marsupials in Australia and South America is best explained by:

  • Continental drift and the migration of marsupials via a land connection between the continents. (correct)
  • A single migration event from Australia to South America.
  • Convergent evolution due to similar environmental conditions.
  • Independent creation events on each continent.

If a species of bird colonizes a remote island, which of the following evolutionary patterns is most likely to occur?

  • The island population will revert to ancestral traits that were lost in the mainland population.
  • The island population will remain genetically identical to the mainland population due to constant gene flow.
  • The island population will evolve in isolation, potentially leading to unique adaptations and speciation. (correct)
  • The island population will immediately go extinct due to limited resources.

Scientists discover a new species of flightless bird on an isolated island. Which of the following pieces of evidence would best support the hypothesis that this bird evolved from a flying ancestor?

<p>The bird's DNA shares significant sequence similarity with the DNA of flying birds. (C)</p> Signup and view all the answers

Considering both molecular data and biogeography, which of the following scenarios would provide the strongest evidence for common ancestry between two distantly located species?

<p>The species have homologous genes with slight sequence variations and their current distributions align with known patterns of continental drift. (A)</p> Signup and view all the answers

Which of the following analogies best represents the relationship between microevolution and macroevolution?

<p>Microevolution is the seed, while macroevolution is the fully grown tree. (D)</p> Signup and view all the answers

If a biologist is studying the change in allele frequencies in a population of butterflies over several generations, which area of evolutionary study is the biologist focused on?

<p>Microevolution. (D)</p> Signup and view all the answers

Imagine a population of birds where beak size is heritable. Birds with larger beaks can more easily crack open tough seeds, especially during droughts. What evolutionary mechanism is most likely at play if the average beak size increases in the population over several generations?

<p>Natural Selection. (D)</p> Signup and view all the answers

Which of the following best describes the role of mutation in the process of evolution?

<p>It provides the raw genetic variation upon which other evolutionary forces act. (A)</p> Signup and view all the answers

Darwin and Wallace both were influenced by Malthus' ideas on population. How did Malthus' work contribute to their development of the theory of natural selection?

<p>Malthus' work highlighted the struggle for existence due to limited resources, suggesting that not all individuals survive. (D)</p> Signup and view all the answers

Which of the following best describes the relationship between evolution and the diversity of life?

<p>Evolution explains how the diversity of life arose through descent with modification over billions of years. (A)</p> Signup and view all the answers

Why is the term "prokaryotes" considered useful primarily when referring to cell structure rather than evolutionary relationships?

<p>Because the term prokaryotes encompasses organisms with diverse evolutionary histories, making it inaccurate for depicting evolutionary relationships. (C)</p> Signup and view all the answers

What is the primary significance of a phylogenetic tree in the context of evolution?

<p>It presents a visual representation of the evolutionary relationships between different groups of organisms. (C)</p> Signup and view all the answers

If two species are closely related on a phylogenetic tree, what inference can be made about their ancestry?

<p>They share a distant common ancestor and have undergone divergent evolutionary changes. (B)</p> Signup and view all the answers

How does the estimated extinction rate of species that have lived compare to the number of species currently catalogued?

<p>Over 99% of species that have ever lived are estimated to have gone extinct, far exceeding the number of species currently catalogued. (D)</p> Signup and view all the answers

Which discipline provided support that living organisms arose ~3.7 billion years ago?

<p>Astronomy (A)</p> Signup and view all the answers

Diversity of life can be broadly classified into two kinds of organisms, based on cell structure. What are they?

<p>Prokaryotes and Eukaryotes (A)</p> Signup and view all the answers

What is meant by "descent with modification?"

<p>Closely related species descend from a common ancestor and change over time (B)</p> Signup and view all the answers

Which of the following best describes vestigial structures?

<p>Structures derived from an ancestor that no longer possess the original function. (C)</p> Signup and view all the answers

The Tiktaalik fossil is considered a transitional form because it demonstrates:

<p>Intermediate features between fish and tetrapods. (B)</p> Signup and view all the answers

Which of the following is an example of molecular homology?

<p>The similarity in nucleotide sequences of DNA in chimpanzees and humans. (D)</p> Signup and view all the answers

What is the significance of the progressive movement of nostrils to the top of the skull in cetacean fossils?

<p>It provides evidence for the evolution of blowholes in modern whales from land mammals. (B)</p> Signup and view all the answers

Which of the following is the best explanation for convergent evolution?

<p>The independent evolution of similar traits in different lineages due to similar environmental pressures. (B)</p> Signup and view all the answers

How do developmental homologies support the theory of evolution?

<p>They reveal shared ancestry through similar embryonic structures that may develop into different adult structures. (A)</p> Signup and view all the answers

Which of the following comparisons best illustrates homologous structures?

<p>The forelimbs of a human, a bat, and a whale. (D)</p> Signup and view all the answers

Bioluminescence in various organisms is an example of:

<p>Convergent evolution due to similar environmental pressures. (A)</p> Signup and view all the answers

Which of the following is a key difference between homologous and analogous structures?

<p>Homologous structures share a common ancestry, while analogous structures do not. (B)</p> Signup and view all the answers

How does the fossil record provide evidence for evolution?

<p>By demonstrating a sequence of changes in organisms over time, and identifying ancestral organisms. (D)</p> Signup and view all the answers

Which of the following statements accurately reflects Darwin's concept of inheritance?

<p>Inheritance tends to propagate new and modified forms of selected varieties. (A)</p> Signup and view all the answers

What does Darwin infer from the concept of all organic beings descending from a single primordial form?

<p>All life forms are related and share a common ancestry. (D)</p> Signup and view all the answers

Which of the following is NOT considered direct evidence supporting evolution?

<p>The presence of similar selective pressures leading to analogous traits. (A)</p> Signup and view all the answers

Consider two species that live in very different environments but share several similar DNA sequences. What evolutionary relationship is MOST likely?

<p>Though living in different environments today, the species share a comparatively recent common ancestor. (E)</p> Signup and view all the answers

Why are fossils considered useful in understanding evolutionary relationships?

<p>They present a timeline of changes in organisms over time. (D)</p> Signup and view all the answers

Flashcards

Evolution Mechanisms

Evolution's driving forces: natural selection, sexual selection, genetic drift, and gene flow.

Population (in evolution)

A group of organisms of the same species living within a specific geographic area.

Microevolution

Small-scale changes in trait and allele frequencies within a population.

Macroevolution

Evolution on a grand scale, leading to new species and major trait changes.

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Darwin and Wallace

Proposed natural selection and common descent as key evolutionary mechanisms.

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Prokaryotes

Organisms whose cells lack a nucleus or most other organelles.

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Eukaryotes

Organisms whose cells possess a nucleus and other organelles.

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Evolution

The process by which life changes over time; descent with modification.

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Phylogenetic Tree

A diagram that depicts the evolutionary relationships among organisms.

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Origin of life

The diversity of life arises from the evolution of organisms over billions of years from a common ancestor.

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Descent with modification

Closely related species descend from a common ancestor and change over time.

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The age of life

Evidence from astronomy, geology, chemistry and biology strongly suggests that living organisms arose ~3.7 billion years ago

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Mechanisms of Evolution

The cause of life evolution.

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Molecular Homology

Comparing the percentage of identical amino acids in proteins (like p53) to determine evolutionary relationships.

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Biogeography

The study of the distribution of species and ecosystems in geographic space and through geological time.

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Marsupial Distribution

Marsupials exist only in Australia and South America because they descended from a common ancestor in South America and migrated to Australia via Antarctica when they were connected.

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Island Evolution

Organisms evolve differently on islands due to unique climates, resources, and predators compared to the mainland.

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Phylogenetic Tree (Molecular Data)

Using nucleotide sequences of genes to construct a tree depicting the evolutionary relationships between organisms.

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Inheritance (in evolution)

The principle that selected traits tend to be passed on to future generations.

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Common Descent

The idea that all life forms on Earth share a single common ancestor.

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Fossils

Preserved remains or traces of ancient organisms.

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Fossil Record

Using fossils to piece together evolutionary history.

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Transitional Fossil

A fossil that shows a mix of traits from two different groups of organisms.

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Vestigial Structures

Structures present in an organism that have lost their original function over time.

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Homology

Similarities between organisms due to shared ancestry.

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Structural Homology

Similar structural traits between organisms.

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Developmental Homology

Similarities in embryonic development between different organisms.

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Convergent Evolution

The independent evolution of similar traits in different lineages due to similar environmental pressures.

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Analogous Structures

Traits that are similar between organisms but evolved independently, not from a common ancestor.

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Bioluminescence

The production and emission of light by a living organism.

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Embryonic development

Focuses on a specific developmental stage, revealing similarities and differences.

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Study Notes

  • Unit 1 covers evolution, bacteria, archaea, and eukaryotes. The focal point is the evidence supporting evolution

Intro to Evolution

  • Evolution explains the diversity of life and its underlying mechanisms, including micro and macroevolution
  • Charles Darwin and Alfred Wallace are key figures in understanding evolution

Diversity of Life

  • Living organisms are classified into prokaryotes and eukaryotes based on their cell structure
  • Prokaryotes lack a nucleus and most organelles
  • Eukaryotes possess a nucleus and other organelles
  • Approximately 1.24 million species have been cataloged, with an estimated 8.74 million alive today
  • Over 99% of all species that have ever lived are now extinct

Evolution's Explanation

  • Living organisms arose approximately 3.7 billion years ago and have been evolving ever since
  • Evolution is a descent with modification and closely related species can descend from a common ancestor, changing over time
  • A phylogenetic tree depicts the relationships between groups of organisms

Mechanisms Driving Evolution

  • Key driving forces are natural selection, genetic drift, gene flow, and sexual selection
  • Evolution can be viewed as a bus: drivers are the forces, fuel is mutations, and the tracks left behind are the branches on a phylogenetic tree

Microevolution vs Macroevolution

  • Evolution is essentially changes in a population
  • Population refers to a group of organisms of the same species in a specific area
  • Change in the genotype impacts the phenotype
  • Microevolution involves changes in trait and allele frequencies within a population, driven by natural selection and other mechanisms
  • Macroevolution is the evolution of new species, traits and broader groups of organisms
  • Macroevolution results from the combination of microevolution, new mutations, and extensive time

Darwin and Wallace

  • Charles Darwin and Alfred Wallace proposed natural selection as a mechanism for evolution
  • They also proposed the concept of common descent, suggesting all living things are related and share a common ancestor

Evidence for Evolution

  • Multiple lines of evidence support evolution
  • These include the fossil record, homologous structures, convergent evolution, developmental homologies, molecular homologies, and biogeography

Fossil Record

  • Fossils uncover and identify ancestral organisms
  • Arranging fossils by date allows reconstruction of evolutionary scenarios
  • Tiktaalik showed the evolution of tetrapods from fish
    • Tiktaalik serves as a transitional form with intermediate features, such as a skull and wrists

Evolution of Whales

  • Modern whales evolved from land mammals, supported by the fossil record
  • Nostrils progressively moved to the top of the skull, forming blowholes in modern whales
  • Progressive loss of hind-limbs, with some extant whales having vestigial hips, is observed in the fossil record
  • Vestigial structures are derived from ancestors but no longer possess the original function

Homology Explained

  • Homology is similarity in organisms due to shared ancestry
  • Homologies exist at structural and molecular levels
  • Structural homologies are similarities in external or internal structures
  • Developmental homologies are structural homologies appearing during embryonic development
  • Molecular homologies involve similarities in DNA or protein sequences

Structural Homology

  • Closely related species share more similar structures/traits
  • Homologous structures/traits come from a common ancestor
  • Forearms of tetrapods have homologous bones despite different functions

Convergent Evolution

  • Similar traits evolve independently and aren't always evidence of relatedness
  • Analogous structures/traits make determining relatedness difficult
  • Convergent evolution arises when similar selective pressures favor similar traits
  • Streamlined bodies of sharks and dolphins are an example

More About Convergence

  • Bioluminescence, the ability to produce light, is a classic example of convergent evolution, arising independently

Homology vs Analogy

  • Homologous traits are similar traits derived from a common ancestor
  • Analogous traits are similar traits not present in the common ancestor

Developmental Homologies

  • Related organisms possess structural homologies during embryonic development of different structures at adult stages
  • Vertebrate embryos exhibit pharyngeal arches and bony tail (which give rise to different structures)
  • "Ontogeny recapitulates phylogeny" means organism's ancestral lineage is seen throughout its development

Molecular Homologies

  • Molecular homologies are similarities in DNA or protein sequences
  • Closely related organisms share greater similarity in DNA or protein sequences
  • Comparing amino acids shows evolutionary relationships

Molecular Homology Evidence

  • The phylogenetic tree of great apes was created by comparing the nucleotide sequence of genes
  • This tree aligns with the tree built using morphological data
  • Human DNA is more similar to Neanderthal and Denisovan DNA than chimpanzee DNA

Biogeography Explained

  • Biogeography studies of organism distribution across space and time
  • Geographical distribution aligns with evolution and continental drift
  • Marsupials exist primarily in Australia and South America
  • Fossil and genetic evidence indicates marsupials descended from a common ancestor in South America
  • Some marsupials migrated to Australia approximately 50 million years ago via Antarctica

Islands

  • Organisms on islands may evolve differently from their mainland counterparts due to variations in climate, resources, and predators

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Evidence for Evolution PDF

Description

Evolution explains the diversity of life and its mechanisms like micro and macroevolution. Key figures are Charles Darwin and Alfred Wallace. Life is classified into prokaryotes and eukaryotes based on cell structure, arising about 3.7 billion years ago.

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