Excites electrons which they used to power biochemical reaction Dark Reaction o

Excites electrons which they used to power

This preview shows page 8 - 11 out of 21 pages.

Excites electrons which they used to power biochemical reaction Dark Reaction o Do not require sunlight directly o CO2 chemically incorporate into carbo… via colvinoben solar cycle C5 Plants o Produces some CO2 via C = H2 o All cillien plants C4 Plants o Increase H2O use inherent in whatever dryer environment o Forward Animal Adaptations to the Environment Homeostasis o Maintenance of a relatively stable internal env. w/ respect to an unstable external env. Generally within very narrow limit Depends upon negative feedback loops o Temperature regulation (thermoregulation) Endothermy – generating heat internally Results in homeothermy – stable internal body temp. o Bird and mammals Can remain active regardless of the env. o Have high energy requirements to produce internal heat Energy less allocated to growth and development (grow slow) Cannot fast when food scarce Need to actively heat the body dictates metabolic rate (BMR) o Smaller the animal, higher the surface area to volume ratio and higher heat loss = higher metabolic rate = more food = short life o As size increases, surface area increases at a slower rate than volume Ectothermy – gain heat from env. Results in paikilothermy o Variable internal temperature All invertebrates, amphibians, reptiles, most fish External env. Dictates activity levels Low metabolic requirements o Energy more allocated to growth than int. temp. Can fast when food scarce
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o Need to passively heat body dictates max body size Bigger you are, the longer you need to heat up Heterotherm Combination of both adaptations o Some sharks, some fish, bees o Counter current heat exchange Torpor Hibernation o Decreased activity level due to cold and/or food scarcity Turtles, bears Estivation o Decreased activity level due to excessive heat and resource scarcity Lung fish Circadian rhythms o Governed by pineal gland (master gland) o 24 hour light/dark cycle governs timing of daily/seasonal physical/physiological activity Day length is often signal to act w/ regard to env. Reproduction, hibernation, birth, etc. Some oceanic organisms responses timed by moon’s cycles Coral reproduction Diurnal o Active during the day o Derive energy from the sun Reptiles o Advantages Can see prey without specialized senses o Disadvantages Visible to predators Need camouflage o Thermoregulation – need to deal with excess heat that you build up during the day Nocturnal o Active at night o Fewer heterotherms o Need specialized senses (smell, sight, or hearing) o No camouflage Crepuscular o Active at dawn and dusk o Ex. Lions o Mix of diurnal and nocturnal adaptations
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Life History Patterns Sexual Reproduction Chart Gamete Production High Low Mate Selection Not selective Very selective - Genetically Novel 50:50 to Births are expendable always choose Competition for Mates High Very Low Parental Investment Low
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