Ecology Exam 1

Gen Ecology
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flow of energy and nutrients through the physical and biological systems
factors that influence the relative abundance of a species.
rates of birth and death, distribution of individuals
process by which the properties of populations change over generations... "Decent with modification from a single common ancestor"
class of individuals with common characteristics, qualities
two copies of the same allele (gene)
different alleles on each chromosome
the particular combination of alleles present at a locus
the outward appearance of an organism
dominant allele is that which is expressed and masks the other
recessive allele is masked and not expressed
the vertical region where water temperature declines most rapidly-depends on solar radiation input and level of mixing
those that feed on detritis-dead plant and animal matter-takes in food then digest unlike decomposer
the dropping of body temp to approx ambient temp for a part of each day, regardless of the season-Hummingbirds, bats, mice
blood circulation system, found in sharks and tunas and allows them to keep internal temps higher than external ones
animals that regulate body temps by both endothermy and ectothermy-bats bees hummingbirds
development of an egg without fertilizing
-animals can remain active regardless of env temps-animals must consume a lot of food to meet the energy demands of endothermy-->a minor amount of energy goes to growth
-animals can allocate more of their energy to biomass production-animals require fewer calories per gram of body weight so can colonize ares of limited food and water
-maintain body temp by oxidizing glucose in cellular respiration -Oxidation is not completely efficient and some energy is lost as heat-Homeothermic respiration rate is proportional to body mass-the thermoneutral zone is a range os env temps within which the metabolic rates are minimal-Metabolic rate increases beyond the critical temps above and below the thermoneutral zone.-Homeotherms maintain a high level of energy through aerobic respiration---They can sustain high levels of physical activity for long periods
Homeotherms regulate exchange between the body and env by: (3 ways)
1- insulation ----fur, feathers, body fat2-shivering---brown fat oxidation (prevalent in hibernators and human infants)3-Evaporative Cooling-sweating, panting and gular fluttering, wallow in water and wet mud
animals that aquire heat from the external env--fish, amphibians, reptiles, insects, and other invertebrates-env sources of heat control the rates of metabolism and activity amongst most poikilotherms-have upper and lower thermal limit they can tolerate-low m.r.-aquatic poik. are poorly insulated and heat is easily transferred from animal to env
a long seasonal torpor characterized by cessation of activity-terrestrial poikilotherms, heterothermic mammals
plants have separate male and female flowers on the same plant
plants have respective male and female organs
involves the formation of a lasting bond between one male and one female-common in birds, rare in mammals
the acquisition by an ind of two or more mates
ind female pairs with two or more males-relatively rare
an ind male pairs with two or more females
males and females mate with one or more of the opposite sex and form no pair bond
What are the 3 types of natural selection?
1- Directional selection occurs when the extreme value of the trait is favored.2- Stabalizing selection occurs when the mean value of the trait is favored.3- Disruptive selection occurs when the members of a pop are subjected to different selection pressures.
Explain the rain shadow effect
Prevailing winds travel up the mountainside, and is it does so, the falling temps cause the air to lose much of its moisture as precipitation. Therefore, rainfall and moist air prevails on the windward side of a mountain range while arid, moisture poor air prevails on the leeward side of a mountain range.
How does the leaf area index affect the amount of light reaching the ground level at the base of the tree?
Cumulative leaf area and LAI increase as you move down from the top of the forest canopy to the ground. The ratio of red to far-red radiation decreases through the canopy.
Which type of leaf is most efficient at heat exchange?
a leaf perpendicular to the sun absorbs 1.0 unit of light energy. vs. a leaf at a 60 degree angle which only absorbs 0.5 unit of light energy.
Is more water required or created by photosynthesis?
required.6H20 + 6 CO2 ---> C6H12O6 + 6 O2
What are the advantages and disadvantages of opening stomata for plants in arid conditions?
stomata are a doorway for CO2, O2, and H2O.through the stomata the plant is able to obtain CO2 but it also loses water by evaporation when the pores are open. Some plants cope with the water loss by having fewer stomata, or by only having the stomata open at night when it is cooler to prevent water loss by evaporation.
How does body size affect metabolism for homeotherms?
the smaller the org's (larger SA/V), the greater the relative heat loss to the surrounding environment.-this heat loss must be offset by increased metabolic activity.
What types of animals would you expect to be heterotherms?
bats, bees, hummingbirds
Compare the types of lungs found in the major animal groups
1- Tracheal system-insects, some aquatic insects2-Lungs-mammals, birds, reptiles, (aquatic)marine mammals3-Lungs and Vascularization-amphibians4-Air Sacs- birds5-Diffusion- small animals (aquatic)6-Gills-found in fish and other marine invertebrates (mollusks, echinoderms)---countercurrent exchange of oxygen between blood in gills and flowing water
Describe the reasons why latitude would affect clutch size.
-Birds in temperate regions have larger clutch size than those in lower latitudes....same for mammals/larger litters, and lizards insects and plants follow similar pattern.3 PROPOSED HYPOTHESIS:1- Clutch size is related to food supply---> more food is available in spring temperate zones.
2-Periodic local climatic catastrophes- (common in temperate regions) can restrict pop size even when resources are plentiful-->org's respond with larger clutches and higher rate of pop increase.
3-Clutch size is directly proportional to resource variation (food) and is inversely related to winter and food supply.
Compare r-strategists and k-strategists
r-Strategists: -short-lived-inhabit unstable/unpredictable environments that can cause catastrophic mortality.-high reproductive rates-rapid development-small body size-large number of offspring-minimal parental care-resources are rarely limiting, weather/climate arek-Strategisits:-competitive spp w/stable pop's of long-lived ind's-delayed and repeated reproduction-larger body size-slower development-produce few young-mortality is related to density, (too many, run out of food)
Define the different types of herbivores
-characterized by the type of plants they eatGRAZERS: grass and leavesBROWSERS: woody materialsGRANIVORES: seedsFRUGIVORES: fruitNECTIVORES: nectar or sap
What are 4 types of asexual reproduction?
Rhizomes: strawberry plantsSplitting in two: parameciumBudding: hydra (plant yeast cells)Parthenogenesis: aphids (snakes)
What are the advantages/disadvantages of asexual reproduction?
Benefits:-offspring are well adapted to current conditions-potential for high pop growthCosts:-low genetic variability in the pop-May be unable to adapt to a change in env'l conditions
Compare the 2 different options for parental investment
1-Large numbers of offspring:-produced by org's that inhibit disturbed sites, unpredictable env's, or env's where parental care is impossible-increase the chances that some young will survive
2-Parents that produce few young can expend more energy on each.
Parental care is best developed among social insects ex)bees
Compare altricial and precocial offspring
Altricial: young are born or hatched in a helpless condition and require considerable parental care (e.g., mice)
Precocial: young emerge from womb ready to move about and forage for themselves (e.g., ungulate mammals)

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