Evolution, and Zoology Theory of Evolution by Natural Selection



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  • Welcome
  • Introduce Zoology
  • Syllabus
  • Lecture
    • Evolution, and Zoology
    • Theory of Evolution by Natural Selection
    • Origin of Species
    • Properties of Life Origins of Life
    • Prokaryotic and Eukaryotic
    • Levels of organization
    • Cell division and inheritance
  • Biology is the study of Life
  • Single cell to multicellular organisms
  • Cell is the basic unit of life
  • Unique plant cell and animal cell
  • Zoology- zoon, animal + logos, to study
    • is the study of Animals
  • Is one of the broadest fields in all of science
    • Variety of animals
    • Complexity of and the processes
  • Specializations in Zoology
  • Anatomy
  • Ecology
  • Genetics
  • Parasitology
  • Physiology
  • Entomology-
  • Ichthyology-
  • Ichthyologist-
  • work to understand structure, function, ecology and evolution of fishes
  • Studies have uncovered an amazing diversity of fishes
  • Cichlid (‘sick-lid’)- freshwater perch-like fishes
  • 1000 species in Africa
  • 300 in South America
  • 3 in India
  • 1 in North America
  • Members of this group
  • Variety of color patterns
  • Habitats
  • Body forms
  • Feeding habits
  • Eretmodus
  • Nip algae with chisel-like teeth
  • Tanganicodus
  • Insect pickers
  • Perissodus
  • Scale eaters
  • Brood their young
  • Dogtooth cichlid
  • The Fontosa
  • Body form

An Evolutionary Perspective

  • Share a common evolutionary past and evolutionary forces that influence their history
    • Resulted in 4 to 100 million species of animals
  • Understand evolutionary process to understand
    • What it is
    • How it originated

Lamarck’s Theory of Evolution

  • Lamarck hypothesized that species evolve
    • Through use and disuse and the inheritance of acquired traits
    • But the mechanisms he proposed are unsupported by evidence
  • Figure 22.4

Fossils, Cuvier, and Catastrophism

  • The study of fossils
    • Helped to lay the groundwork for Darwin’s ideas
  • Fossils are remains or traces of organisms from the past
  • Figure 22.3
  • Darwin’s interest in the geographic distribution of species
    • Was kindled by the Beagle’s stop at the Galápagos Islands near the equator west of South America
  • Figure 22.5
  • England
  • EUROPE
  • NORTH
  • AMERICA
  • Galápagos
  • Islands
  • Darwin in 1840,
  • after his return
  • SOUTH
  • AMERICA
  • Cape of
  • Good Hope
  • Cape Horn
  • Tierra del Fuego
  • AFRICA
  • HMS Beagle in port
  • AUSTRALIA
  • Tasmania
  • New
  • Zealand
  • PACIFIC
  • OCEAN
  • Andes
  • ATLANTIC
  • OCEAN

Darwin’s Focus on Adaptation

  • As Darwin reassessed all that he had observed during the voyage of the Beagle
    • He began to perceive adaptation to the environment and the origin of new species as closely related processes
  • From studies made years after Darwin’s voyage
    • Biologists have concluded that this is indeed what happened to the Galápagos finches
  • Figure 22.6a–c
  • (a) Cactus eater. The long, sharp beak of the cactus ground finch (Geospiza scandens) helps it tear and eat cactus flowers and pulp.
  • (c) Seed eater. The large ground finch (Geospiza magnirostris) has a large beak adapted for cracking seeds that fall from plants to the ground.
  • (b) Insect eater. The green warbler finch (Certhidea olivacea) uses its narrow, pointed beak to grasp insects.
  • In 1844, Darwin wrote a long essay on the origin of species and natural selection
    • But he was reluctant to introduce his theory publicly, anticipating the uproar it would cause
  • In June 1858 Darwin received a manuscript from Alfred Russell Wallace
    • Who had developed a theory of natural selection similar to Darwin’s
  • Darwin quickly finished The Origin of Species
    • And published it the next year

Resistance to the Idea of Evolution

  • The Origin of Species
    • Shook the deepest roots of Western culture
    • Challenged a worldview that had been prevalent for centuries

Descent with Modification

  • The phrase descent with modification
    • Summarized Darwin’s perception of the unity of life
    • States that all organisms are related through descent from an ancestor that lived in the remote past
  • In the Darwinian view, the history of life is like a tree
    • With multiple branchings from a common trunk to the tips of the youngest twigs that represent the diversity of living organisms
  • Figure 22.7
  • Hyracoidea
  • (Hyraxes)
  • Sirenia
  • (Manatees
  • and relatives)
  • Years ago
  • Millions of years ago
  • Deinotherium
  • Mammut
  • Stegodon
  • Mammuthus
  • Platybelodon
  • Barytherium
  • Moeritherium
  • Elephas
  • maximus
  • (Asia)
  • Loxodonta
  • africana
  • (Africa)
  • Loxodonta
  • cyclotis
  • (Africa)

Natural Selection and Adaptation

  • Evolutionary biologist Ernst Mayr
    • Has dissected the logic of Darwin’s theory into three inferences based on five observations
  • Observation #1: For any species, population sizes would increase exponentially
    • If all individuals that are born reproduced successfully
  • Figure 22.8
  • Observation #2: Nonetheless, populations tend to be stable in size
    • Except for seasonal fluctuations
  • Observation #3: Resources are limited
  • Inference #1: Production of more individuals than the environment can support
    • Leads to a struggle for existence among individuals of a population, with only a fraction of their offspring surviving
  • Observation #4: Members of a population vary extensively in their characteristics
    • No two individuals are exactly alike
  • Figure 22.9
  • Observation #5: Much of this variation is heritable
  • Inference #2: Survival depends in part on inherited traits
    • Individuals whose inherited traits give them a high probability of surviving and reproducing are likely to leave more offspring than other individuals
  • Inference #3: This unequal ability of individuals to survive and reproduce
    • Will lead to a gradual change in a population, with favorable characteristics accumulating over generations

Artificial Selection

  • In the process of artificial selection
    • Humans have modified other species over many generations by selecting and breeding individuals that possess desired traits
  • Figure 22.10
  • Terminal
  • bud
  • Lateral
  • buds
  • Brussels sprouts
  • Cabbage
  • Flower
  • cluster
  • Leaves
  • Cauliflower
  • Flower
  • and
  • stems
  • Broccoli
  • Wild mustard
  • Kohlrabi
  • Stem
  • Kale

Summary of Natural Selection

  • Natural selection is differential success in reproduction
    • That results from the interaction between individuals that vary in heritable traits and their environment
  • Natural selection can produce an increase over time
    • In the adaptation of organisms to their environment
  • Figure 22.11
  • (a) A flower mantid in Malaysia
  • (b) A stick mantid in Africa
  • Darwin’s theory explains a wide range of observations
  • Darwin’s theory of evolution
    • Continues to be tested by how effectively it can account for additional observations and experimental outcomes

Evolutionary Processes

  • Organic evolution- change in the genetic makeup of populations over time.
    • Source of animal diversity
    • Explains family relationships within animal groups
  • Charles Darwin
  • Published evidence of evolution 1859
  • Proposed a mechanism
  • Understanding diversity of animal structure and function arose is one of the many challenges
  • i.e cichlid scale eaters of Africa

Animal classification and Evolutionary Relationship

  • Evolution not only explanation why animals appear and function as they do
  • It explains family relationships
  • i.e cichlid species
    • Groups share more of their DNA
    • Thus resemble each other
    • Genetic studies suggest
      • Oldest African cichlid found in Lakes Tanganyika and Kivu
      • These fish invades rivers, lakes Malawi, Victoria and others
      • Most rapid known origin of species of any animal groups

Figure 1.3

  • The Origin of Species
    • Focused biologists’ attention on the great diversity of organisms
  • Figure 22.1
  • Darwin made two major points in his book
    • He presented evidence that the many species of organisms presently inhabiting the Earth are descendants of ancestral species
    • He proposed a mechanism for the evolutionary process, natural selection
  • The Darwinian revolution challenged traditional views of a young Earth inhabited by unchanging species
  • In order to understand why Darwin’s ideas were revolutionary
    • We need to examine his views in the context of other Western ideas about Earth and its life
  • The historical context of Darwin’s life and ideas
  • Figure 22.2
  • Linnaeus (classification)
  • Hutton (gradual geologic change)
  • Lamarck (species can change)
  • Malthus (population limits)
  • Cuvier (fossils, extinction)
  • Lyell (modern geology)
  • Darwin (evolution, nutural selection)
  • Mendel (inheritance)
  • Wallace (evolution, natural selection)
  • 1750
  • American Revolution
  • French Revolution
  • U.S. Civil War
  • 1800
  • 1850
  • 1900
  • 1795
  • Hutton proposes his theory of gradualism.
  • 1798
  • Malthus publishes “Essay on the Principle of Population.”
  • 1809
  • Lamarck publishes his theory of evolution.
  • 1830
  • Lyell publishes Principles of Geology.
  • 1831–1836
  • Darwin travels around the world on HMS Beagle.
  • Darwin begins his notebooks on the origin of species.
  • 1837
  • Darwin writes his essay on the origin of species.
  • 1844
  • Wallace sends his theory to Darwin.
  • 1858
  • The Origin of Species is published.
  • 1859
  • Mendel publishes inheritance papers.
  • 1865

Homology, Biogeography, and the Fossil Record

  • Evolutionary theory
    • Provides a cohesive explanation for many kinds of observations

Homology

  • Homology
    • Is similarity resulting from common ancestry

Anatomical Homologies

  • Homologous structures between organisms
  • Figure 22.14
  • Human
  • Cat
  • Whale
  • Bat
  • Comparative embryology
    • Reveals additional anatomical homologies not visible in adult organisms
  • Figure 22.15
  • Pharyngeal
  • pouches
  • Post-anal
  • tail
  • Chick embryo
  • Human embryo
  • Vestigial organs
    • Are some of the most intriguing homologous structures
    • Are remnants of structures that served important functions in the organism’s ancestors

Molecular Homologies

  • Biologists also observe homologies among organisms at the molecular level
    • Such as genes that are shared among organisms inherited from a common ancestor

Homologies and the Tree of Life

  • The Darwinian concept of an evolutionary tree of life
    • Can explain the homologies that researchers have observed
  • Anatomical resemblances among species
    • Are generally reflected in their molecules, their genes, and their gene products
  • Figure 22.16
  • Species
  • Human
  • Rhesus monkey
  • Mouse
  • Chicken
  • Frog
  • Lamprey
  • 14%
  • 54%
  • 69%
  • 87%
  • 95%
  • 100%
  • Percent of Amino Acids That Are
  • Identical to the Amino Acids in a
  • Human Hemoglobin Polypeptide

Biogeography

  • Darwin’s observations of the geographic distribution of species, biogeography
    • Formed an important part of his theory of evolution
  • Sugar
  • glider
  • AUSTRALIA
  • NORTH
  • AMERICA
  • Flying
  • squirrel
  • Figure 22.17

The Fossil Record

  • The succession of forms observed in the fossil record
    • Is consistent with other inferences about the major branches of descent in the tree of life

Binomial nomenclature

  • Karl von Linne (1707-1778)
  • Named and classified plants into hierarchy of relatedness
  • Binomial Nomenclature- systematic way of naming organisms-
    • Two part name describes each kind of organism
    • First part- indicates the genus
    • Second part indicates the species to which the organism belongs.
    • i.e. Perissodus microlepis
  • The Darwinian view of life
    • Predicts that evolutionary transitions should leave signs in the fossil record
  • Paleontologists
    • Have discovered fossils of many such transitional forms
  • Figure 22.18

What Is Theoretical about the Darwinian View of Life?

  • In science, a theory
    • Accounts for many observations and data and attempts to explain and integrate a great variety of phenomena

Figure 1.4

  • Hierarchy of Relatedness
  • Evolutionary concepts hold the key to understanding
    • why animals look and act
    • Habitat
    • Characteristics

Ecological Perspective

  • Ecology- (Gr. okois, house + logos, to study)
  • Study of the relationships between organisms and their environment
  • Human dependence on animals (food, medicine, clothing)
  • Humans upset the delicate ecological balances that has evolved

In the 1950’s in an attempt to increase the lake’s fishery

  • Nile perch introduced into Lake Victoria
  • Reduced cichlid population from 99% to <1%
  • Most cichlid feed on algae, the algae grew
  • Algae died and decayed
  • Lake depleted of oxygen
  • Introduced nonnative plant (water hyacinth)
  • Water hyacinth has overgrown and resulted in further habitat loss

Figure 1.6 (a)

Figure 1.6 (b)

EC Figure

  • Chapter 1
    • Evolution, Ecology and Zoology
  • Chapter 4
    • Theory of Evolution by Natural Selection
    • Microevolution and Macroevolution
  • Chapter 2
    • Properties of Life Origins of Life
    • Prokaryotic and Eukaryotic
    • Levels of organization
    • Cell division and inheritance
  • Chapter 3
    • Mitotic
    • Meiosis


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