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Evolution, and Zoology Theory of Evolution by Natural Selection
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| Date | 07.12.2018 | | Size | 3.38 Mb. |
| - 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 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
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- Members of this group
- Variety of color patterns
- Habitats
- Body forms
- Feeding habits
- Eretmodus
- Nip algae with chisel-like teeth
- Tanganicodus
- Insect pickers
- Brood their young
- Dogtooth cichlid
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
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
- 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
- Darwin in 1840,
- after his return
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
- (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
- 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
- Sirenia
- (Manatees
- and relatives)
- 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
- 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
- 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
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
- (a) A flower mantid in Malaysia
- (b) A stick mantid in Africa
- If an environment changes over time
- 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
- 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
- Linnaeus (classification)
- Hutton (gradual geologic change)
- Lamarck (species can change)
- Malthus (population limits)
- Cuvier (fossils, extinction)
- Darwin (evolution, nutural selection)
- Wallace (evolution, natural selection)
- Hutton proposes his theory of gradualism.
- Malthus publishes “Essay on the Principle of Population.”
- Lamarck publishes his theory of evolution.
- Lyell publishes Principles of Geology.
- Darwin travels around the world on HMS Beagle.
- Darwin begins his notebooks on the origin of species.
- Darwin writes his essay on the origin of species.
- Wallace sends his theory to Darwin.
- The Origin of Species is published.
- Mendel publishes inheritance papers.
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
- Comparative embryology
- Reveals additional anatomical homologies not visible in adult organisms
- 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
- 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
- Some similar mammals that have adapted to similar environments
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
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 - 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
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