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Evolution & Morphology General Zoology, 18 January 2008 Donald Winslow Readings from Hickman et al. 2008: Ch. 6 pp 105-113, 115-130,132-134 Ch. 9 pp 186-190,

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Presentation on theme: "Evolution & Morphology General Zoology, 18 January 2008 Donald Winslow Readings from Hickman et al. 2008: Ch. 6 pp 105-113, 115-130,132-134 Ch. 9 pp 186-190,"— Presentation transcript:

1 Evolution & Morphology General Zoology, 18 January 2008 Donald Winslow Readings from Hickman et al. 2008: Ch. 6 pp , , Ch. 9 pp ,

2 Founders of evolution Lamarck—inheritance of acquired traits Lyell—uniformitarianism & gradualism Malthus—exponential growth & limitation Darwin—natural selection, speciation Wallace—independently developed theory of evolution by natural selection & inspired Darwin to publish.

3 Charles Darwin Voyage on H.M.S. Beagle, Galapagos Natural selection & adaptation –Population growth & limits to growth –Competition and heritable variation –Differential survival & reproduction –Gradual adaptation & speciation Reproductive barriers & speciation

4 Evidence for evolution Fossil record –Marine organisms on mountaintops Geological time & dating—isotope decay Evolutionary trends—horses Homology of vertebrate forelimbs (Fig 6.14) “Ontogeny recapitulates phylogeny.” –Haeckel

5 Flying Great Egret (Ardea alba). Photo by Karen Bays. Bird wings are homologous to a human’s arms.

6 Ontogeny & phylogeny Pharyngeal gill slits Paedomorphosis Heterochrony

7 Microevolution Population genetics Gene pool Allele frequencies Hardy-Weinberg equilibrium

8 Forces that change allele frequencies Mutation Genetic drift Nonrandom mating—e.g. assortative mating Migration Selection (natural, artificial, sexual) –Relative fitness –Stabilizing, directional, & disrupting selection

9 Bright plumage of male Northern Cardinal— A result of sexual selection.

10 Measuring genetic variation Protein polymorphism & heterozygosity Gel electrophoresis Quantitative characters Dark-eyed Junco (Junco hyemalis) color variants

11 Macroevolution Allopatric & sympatric speciation Hybridization, extinction Adaptive radiation (diversification) Gradualism, punctuated equilibrium Mass extinction Levels of selection –Genic, individual, kin, group, species

12 Morphology Biological hierarchy Grades of organization & body plans Describing locations on animal bodies Body cavities & germ layers Developmental patterns Histology Body size

13 Biological hierarchy Cell Tissue Organ Organ system Organism Population Community Nine-banded armadillo

14 Grades of organization Protoplasmic (e.g. protozoa) Cellular (e.g. colonial protists, sponges) Tissue (e.g. jellyfish) Organ (e.g. flatworm) Organ system (e.g. molluscs, arthropods) Luna moth

15 Body plans Unicellular protists vs multicellular animals –Protozoa vs Metazoa Cell-level vs tissue-level organization –Porifera vs Eumetazoa Radial symmetry vs bilateral symmetry Sac vs “tube-within-a-tube” digestive tracts Acoelomate, pseudocoelomate, coelomate

16 Describing location on animal Anterior/posterior Dorsal/ventral Medial/lateral Distal/proximal Frontal, sagittal, and transverse planes

17 Body cavities Blastocoel Gastrocoel (archenteron) Pseudocoel Coelom

18 Germ layers Endoderm Mesoderm Ectoderm

19 Developmental patterns Cleavage—radial or spiral Gastrulation (germ layer formation) Diploblastic or triploblastic Protostome or deuterostome Metamerism (segmentation)

20 Histology Blood plasma and interstitial fluids Tissues Endoderm  epithelium of digestive tract Ectoderm  skin & nervous tissue Mesoderm  connective tissue, muscles, viscera –Connective tissue: »collagen, blood, lymph, cartilage, bone, fat

21 Advantages & disadvantages of large body size Predators can subdue larger prey, But larger prey can’t hide as easily. Larger animals have efficient metabolism, But use more energy. Larger animals have longer generations.

22 Humpback whale


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