Science of Zoology and Evolution of Animal Diversity Chapter 1 Science of Zoology and Evolution of Animal Diversity Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

ZOOLOGY—STUDY OF ANIMALS Life began over 600 million years ago Evolution of -multicellularity, coelom, vertebrae, homeothermy

Fundamental Properties of Life Does Life Have Defining Properties? What is life? No simple definition The history of life shows extensive and ongoing change called evolution Answer must be based on the common history of life on earth

General Properties of Living Systems Chemical Uniqueness: Living systems demonstrate a unique and complex molecular organization Small molecules are assembled into macromolecules: Nucleic Acids Proteins Carbohydrates Lipids

General Properties of Living Systems Although living systems are composed of the same kinds of atoms obeying the same fundamental laws of chemistry as nonliving matter, the organizational structure of the macromolecules makes them unique

General Properties of Living Systems Complexity and Hierarchical Organization: Living systems demonstrate a unique and complex hierarchical organization In living systems there exists a hierarchy of levels that includes: Macromolecules Cells Organisms Populations Species

General Properties of Living Systems Reproduction: Living systems can reproduce themselves At each level of the biological hierarchy living forms reproduce to generate others like themselves: Genes replicated to produce new genes. Cells divide producing new cells. Organisms reproduce, sexually or asexually, to produce new organisms Populations may fragment to produce new populations Species may split to produce new species

General Properties of Living Systems Possession of a Genetic Program: A genetic program provides fidelity of inheritance DNA: Long, linear, chain of nucleotides containing genetic information Sequence of nucleotide bases in DNA determines the order of amino acids in proteins Genetic Code: correspondence between base sequences in DNA and the sequence of amino acids in a protein

General Properties of Living Systems Metabolism: Living organisms maintain themselves by acquiring nutrients from their environments Metabolic processes include: Digestion Energy production (Respiration) Synthesis of required molecules and structures by organisms

General Properties of Living Systems Metabolism is often viewed as an interaction of destructive (catabolic) and constructive (anabolic) reactions The most fundamental anabolic and catabolic chemical processes used by living systems arose early in the evolutionary history of life

General Properties of Living Systems Development: All organisms pass through a characteristic life cycle Development describes the characteristic changes that an organism undergoes from its origin to its final adult form

General Properties of Living Systems Environmental Interaction: All animals interact with their environments Ecology: The study of organismal interaction with an environment All organisms respond to environmental stimuli

General Properties of Living Systems Movement: Living systems and their parts show precise and controlled movements arising from within the system Living systems extract energy from their environments permitting the initiation of controlled movements

General Properties of Living Systems Movements at the cellular level are required for: Reproduction Growth Responses to stimuli Development in multicellular organisms On a larger scale: Entire populations or species may disperse from one geographic location to another over time

Life Obeys Physical Laws The complex molecular organization in living cells is attained and maintained only as long as energy fuels the organization Survival, growth, and reproduction of animals require energy that comes from breaking complex food molecules into simple organic waste

Zoology As Part of Biology Animals originated in the Precambrian seas over 600 million years ago Characteristics of Animals: Eukaryotes: cells contain membrane-enclosed nuclei Heterotrophs: Not capable of manufacturing their own food and must rely on external food sources Cells lack cell walls

Principles of Science The scientific method may be summarized as a series of steps: Observation Question Hypothesis Formation Empirical Test Controlled Experiment Includes at least 2 groups Test Group Control Group Conclusions Accept or reject your hypothesis Publications

Principles of Science Hypothesis: Potential answers to questions being asked Derived from prior observations of nature or from theories based on such observations Often constitute general statements about nature that may explain a large number of diverse observations If a hypothesis is very powerful in explaining a wide variety of related phenomena, it attains the level of a theory

Principles of Science Powerful theories that guide extensive research are called paradigms The refutement and replacement of a paradigm is known as a scientific revolution Two major paradigms that guide zoological research: Darwin’s Theory of Evolution The Chromosomal Theory of Inheritance

THEORY OF EVOLUTION Charles Darwin and Alfred Wallace In 1859, Darwin published On the Origin of Species THEORY OF EVOLUTION

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Theories of Evolution and Heredity Common Descent All forms of life descended from a common ancestor through a branching of lineages Life’s history has the structure of a branching evolutionary tree, known as a phylogeny Serves as the basis for our taxonomic classification of animals

Theories of Evolution and Heredity Multiplication of Species The evolutionary process produces new species by splitting and transforming older ones Gradualism Large differences in anatomic traits that characterize diverse species originate through the accumulation of many small incremental changes over very long periods of time

Theories of Evolution and Heredity Natural Selection A creative process that generates novel forms from the small individual variations that occur among organisms within a population Adaptation An anatomical structure, physiological process, or behavioral trait that evolved by natural selection and improves an organism’s ability to survive and leave descendants

Theories of Evolution and Heredity Darwin's theory of natural selection faced a major obstacle when first proposed because it lacked a successful theory of heredity Neo-Darwinism Describes Darwin’s theories as modified by incorporating the Chromosomal Theory Of Inheritance

Theories of Evolution and Heredity Mendelian Heredity and the Chromosomal Theory of Inheritance Foundation for current studies of genetics and evolution in animals Genetic Approach Mating populations of organisms that are true-breeding for alternative traits Following hereditary transmission of those traits to offspring

FOSSIL RECORD Hard parts fossilize best Stratification provides chronological information FOSSIL RECORD

Figure 1_10a

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Figure 1_10c

-elaboration of molars Figure 1_14 Evolution of horses -increased size -elaboration of molars -loss of toes

Common descent Bones of vertebrate limbs HOMOLOGY

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WHAT IS A SPECIES? Descend from a common ancestor Exhibit reproductive compatibility WHAT IS A SPECIES?

HOW DO NEW SPECIES APPEAR? Allopatric speciation Adaptive radiation HOW DO NEW SPECIES APPEAR?

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WHEN DOES EVOLUTION OCCUR? Gradualism v. Punctuated Equilibrium WHEN DOES EVOLUTION OCCUR?

Industrial melanism (dark pigmentation) in peppered moths of England NATURAL SELECTION

Changes in frequencies of variant forms of genes within populations. Ex.-blood type MICROEVOLUTION

Figure 1_31 Selection

Population bottleneck Figure 1_29 Population bottleneck

Figure 1_30 Sexual selection