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Biology Lectures #3.docx

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University of Guelph
BIOL 1070
Wright& Newmaster

th November 7 2011 Evolution: The study of both adaptive and non-adaptive change over time in populations, the origin and extinction of species, and the relationships among living things. Ecology: The study of interrelationships between organisms and both living (biotic) and non-living (abiotic) components of their environments. Physiology: The study of organism structure and function, including homeostasis and encompassing cells, tissues, organs, and body systems. Why be concerned? - Biological impacts o Biodiversity changes, disease, migration - Political and economic impacts o Artic sovereignty, natural resources, environmental policy - Aesthetics o Landscapes, tourism - Culture changes o Traditional hunting practices Outline of Inquiry Case #3 1. How climate change impacts organisms on different time scales (Lecture 16, 17) 2. How climate change impacts plants and lichens. (Lecture 18) 3. Physiological responses to temperature change in animals (Lecture 19, 20, 21) 4. Predicting long-term trends in Artic populations. (Lecture 22, 23) Time domains for temperature change Artic plants and animals have lived in the Artic ecosystem for thousands of year. They must cope with temperature change on many different time scales. - Acute (Minutes to hours) - Chronic (Weeks to years) - Generational (Thousands of years of generations) Example  How would an Artic fox versus an Artic char respond to a 5°C increase in temperature if change were: Acute? Chronic? Generational? - Information we need to know o Unicellular or multicellular? o Endotherm or ectoderm? o Is the animal able to avoid the temperature change? o Are there behavioral responses that the animal can invoke to reduce the impact of the temperature change? o What type of physiological responses are possible and at what level? (cell, tissue, organ, etc.) th November 9 2011 Chronic response: Acclimatization - Adjustment by an individual organism to chronic stress. - Physiological processes or structures change to function more optimally under new conditions. - Change is reversible, and may even be repeated. Clicker Question  D th November 13 2011 What abiotic factors challenge Artic plants? - Air Temperature  Tissue damage due to temperature extremes - Wind Speed  High wind desiccation, wind damage - Snow Cover  Shelter from the wind and insulates temperature extremes - Permafrost Depth  Limit access to resources (nutrients/moisture) - Precipitation/Moisture  Lack of moisture below freezing temperature; air is very dry at low temperatures - Sunlight  Short growing season, high UV - Soil Nutrients  Restricted nutrient availability; slow microbial decomposition and mineralization rates of organic matter constrained by low temperatures - Geo-physical  Scouring by ice, snow pack, spring/summer erosion What are the adaptations of Artic plants? - Hair leaves and stem; small size; small leaves - Increased anoxia tolerance; small size; annual life cycle - Deep pigmentation (absorb more radiant energy); Increased respiration; shorter life cycles; Increased importance of vegetative reproduction - Thick waxy cuticle on leaves - Freeze tolerance (-30 to -196 Celsius); Propylene glycol (antifreeze) in cells; cell wall adaptations - Vegetative reproduction, can recover quickly even if many plants damaged - Morphological adaptations for growing in specialized habitats like rock; use of sheltered microhabitats and south-facing slopes - Different strategies for nutrient uptake, and utilization of different sources of nitrogen; recycling mechanisms; mycorrhizal partners Photosystem II: A protein complex associated with Light-dependent reactions. It is located in the thylakoid membrane of plants, algae, and cyanobacteria. Photons of light to energize electrons that oxidize water to form hydrogen ions and molecular oxygen. The hydrogen ions generated by the oxidation of water help to generate ATP (adenosine triphosphate), which is often called the molecular unit of currency. Clicker Question  D Why do lichens thrive in the Artic? - Grow on bare rock - No roots. Instead, rhizines for attaching to substrate - Can extract moisture and nutrients from the air - Tolerant to freezing - Desiccation tolerant - Fungal partner can utilize low amount of nitrogen - Algal partner can photosynthesize a low light levels - Can be dormant for long periods of time - Asexual reproduction Clicker Question  D November 16 2011 Conformer - Allow internal environment to follow changes in the external environment. Regulator - Regulator maintains a constant internal environment (homeostasis) in the face of varying external environment. Heterothermy: Endothermic at certain times or in a certain tissues, but not at all time or in all tissues. (Example: tuna) Which graph represents ecotherms and endotherms? Graph #1  Ecotherm Graph #2  Endotherm Cost/Benefit Analysis
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