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:
Evolution & Morphology General Zoology, 18 January 2008 Donald Winslow Readings from Hickman et al. 2008: Ch. 6 pp , , Ch. 9 pp ,
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.
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
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
Flying Great Egret (Ardea alba). Photo by Karen Bays. Bird wings are homologous to a human’s arms.
Bright plumage of male Northern Cardinal— A result of sexual selection.
Measuring genetic variation Protein polymorphism & heterozygosity Gel electrophoresis Quantitative characters Dark-eyed Junco (Junco hyemalis) color variants
Macroevolution Allopatric & sympatric speciation Hybridization, extinction Adaptive radiation (diversification) Gradualism, punctuated equilibrium Mass extinction Levels of selection –Genic, individual, kin, group, species
Morphology Biological hierarchy Grades of organization & body plans Describing locations on animal bodies Body cavities & germ layers Developmental patterns Histology Body size
Biological hierarchy Cell Tissue Organ Organ system Organism Population Community Nine-banded armadillo
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
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
Describing location on animal Anterior/posterior Dorsal/ventral Medial/lateral Distal/proximal Frontal, sagittal, and transverse planes
Body cavities Blastocoel Gastrocoel (archenteron) Pseudocoel Coelom
Germ layers Endoderm Mesoderm Ectoderm
Developmental patterns Cleavage—radial or spiral Gastrulation (germ layer formation) Diploblastic or triploblastic Protostome or deuterostome Metamerism (segmentation)
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.