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Individuals ESC 556 week 4 Indiviudal • Basic unit • Individuals vary in their conditions • Asexual reproduction Unitary vs. Modular organisms • Unitary organisms • Determined form • Form and sequence • Modular organisms • • • • • • • Units that can produce similar units Sessile Plants – leaves & flowers Genet Much greater variation Time sequences apply to each module Death results from external factors Ecological Physiology • Internal adjustments to external changes • Resist/tolerate • Regulation & Adaptation • Migration • A lot of different environments • Homeostasis – sea to freshwater & land • Conformation & regulation • Eury vs. steno • Poikilo vs. homoio • Ectotherms vs. endotherms Resistance and Tolerance • Stress response • Response curve • Individual differences • Tolerance vs. resistance • Deserts, arctic/antarctic, wavy shores DESERTS • Low densities of life and biodiversity • Dry / daily temperature fluctuations • Conserve water and control temperature • Xerophytes • Seeds at dry periods • Allelopathy • Animals – small & active at night • • • • Snakes & Lizards Metabolic water Insulation Tolerant of dehydration and body temperature fluctuations adaptation • Evolutionary changes over time • Survive competition & complex environmental variables • Long vs. short term adaptation (acclimatization) METABOLIC rate • Amount of energy used per unit time • Growth, reproduction, body maintenance, locomotion • Metabolic rates vary • Basal metabolic rate vs. daily energy expenditure • Life style and body size • Ectotherms – poikilothermic • Endotherms – homoiothermic • 25-30 X METABOLIC rate • Body size • Large organisms • Relative to their body mass METABOLIC rate • Ectotherm strategy – Low energy system • Low resting metabolic rate, torpor, serpentine shapes • Very abundant and diverse • Endotherms – High energy system • Independent of environmental conditions • Foraging at night, inhabiting high latitudes • Lower production efficiency • Assimilation efficiency • 20-90% • Respiration, growth & reproduction • Growth & reproduction efficiency Locomotion • Inertia & drag • Reynolds number • Aquatic organisms • Locomotory activity • Reduction in sinking rates – spines/body extensions behaviour • Survive and reproduce • obtain food, avoid predation, find mates & resources • Respond by growth (plants) or locomotion (animals) • Energetic consequences and requirements Sedentary or mobile • Sessile organisms • • • • • • Low energy but risky Protective mechanisms Tolerating environmental conditions or stable habitat selection Food capture indirect Sexual reproduction difficult Dispersal at any life stage • Mobile organisms • • • • • Escape mechanisms Taxic behaviour & dispersal Food search Sexual reproduction easier Dispersal at any life stage Behavioral mechanisms • Response to biotic and abiotic stimuli • Growth – sexual reproduction • Costs and benefits • Plants • No nervous system – chemical coordination • Tropisms • Phototropism, geotropisms • Nasties • Non-directional movements of part of a plant dIspersal and migration • Passive vs. active dispersal • Individual activities population level consequences • Seasonal, diurnal or tidal cycles effects • Migration: movement of groups of individuals • Key points • Minimize intraspecific competition • Colonize new niches • Response to variation in conditions and resources Avoidance and dispersal • Avoid competition between future generations and parents • Adverse conditions, resource limitations, competition • Spatial avoidance • Temporal avoidance • • • • Diapause Hibernation Aestivation Migration Behavioral mechanisms • Animals • Nervous system • Chemical responses • Innate behaviours • Genetically-based – taxes, kineses & instinctive behaviour • • • • Learned behaviour – habituation & conditioning Imprinting Feeding behaviour Social behaviour – e.g. altruism Reproduction • Genetic material transfer from parental generation to progeny • Asexual • Single parent • Mitosis - Clones • Mutation • Types • • • • • Fission Sporulation Budding Fragmentation Vegetative propagation mitosis reproduction • Sexual Reproduction • Two parents • Fusion of haploid gametes • Energetically costly • Broadcast fertilization • Meiosis • Recombination • Advantages • Variation • • • • Sperm & ova vs. + & Dioecious Hermaphrodites Parthenogenesis Life Cycles and Life history strategy • Zygote of one generation to the next • Alternation of generations • Sporophyte and gametophyte generations Life Cycles and Life history strategy • Cyclic polymorphism Life Cycles and Life history strategy • Parasite life cycles Life Cycles and Life history strategy • Life history • Growth, differentiation, reproduction • Abiotic and biotic interactions • Evolutionary processes • Plasticity • Size • Growth & Development Rates • Reproduction • Storage mechanisms • Dormancy Size • Species, individuals, life stages • Advantages of increased size • • • • Higher competitive ability reproductive success Increase success as a predator Decrease predation risk Reduced surface:volume ratio • Better homeostatic control • Bergmans’s rule • Disadvantages of increased size • Preferred food items • Greater energy requirement Growth and Development Rates • Development: differentiation of morphological and physiological processes • Development vs. growth • Different rates and strategies of development • Early • Arrested Reproduction • Diverse strategies reproduction • Iteroparous vs. semelparous reproduction • Method of fertilization & parental care • Broadcast fertilization • Copulation Storage Mechanisms • Irregular supply of resources • Accumulation during abundance • Fats, starch, glucose • Food stores Dormancy • Periods of adversity • Minimal metabolic activity • Facultative vs. obligate • Forms • • • • Resting spores or buds Diapause Hibernation Aestivation • Resistant external coat • Synchorinization • Predictive vs. consequential strategies Feeding strategies and mechanisms Autotrophic Heterotrophic Photosynthetic All green plants + green & purple sulphur bacteria Few: e.g. purple nonsulphur bacteria Chemosynthetic Nitrogen cycle bacteria Most bacteria, parastiic plants, all fungi + animals Feeding strategies and mechanisms • Photoautotrophs • • • • Light Nutrients Water Carbon Dioxide • Terrestrial plants • Water & Nutrients • Aquatic plankton • Light & Nutrients • Insectivorous plants & nitrogen fixing nodules (legumes) • Photoheterotrophs Feeding strategies and mechanisms • Heterotrophs • Holozoic • Symbiotic • Parasitic • Feeder types • • • • Microphagous Macrophagous Fluid feeders Saprophytes Holozoic nutrition Symbiotic nutrition • Mutualism • Corals • Ruminant mammals • Commensalism ParasitiC Nutrition • Ectoparasites & Endoparasites • Obligate vs. facultative Microphagous Feeders • Pseudopodia & food vacuoles • Cilia • Filter feeders • Setose/ciliary mechanisms Macrophagous Feeders • Scraping & boring • Tentacular • Whole ingestion • Biting and chewing • Detritus Fluid feeders • Sucking – proboscis • Piercing & sucking
