GENERAL BIOLOGY BIOL 1001
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This 5 page Study Guide was uploaded by Cassie Koepp on Tuesday October 13, 2015. The Study Guide belongs to BIOL 1001 at Louisiana State University taught by Christopher Gregg in Fall. Since its upload, it has received 31 views. For similar materials see /class/222823/biol-1001-louisiana-state-university in Biological Sciences at Louisiana State University.
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Date Created: 10/13/15
Chapter Learning Objectives Chapter 41 How Do Ecosystems Work 411What are the pathways of energy and nutrients Describe the fundamental relationship between autotrophs and heterotrophs in an ecosystem Autotrophs produce food for themselves using NONLIVING nutrients N03 and SUNLIGHT Heterotrophs Must acquire energy and many of their nutrients prepackaged in molecules that compose the bodies of other organisms eat their food Explain how the first and second laws of thermodynamics apply to ecosystems lSt law energy moves through the communities within ecosystems in a continuous oneway ow needing constant replenishment from an outside source 2quot law Nutrients constantly cycle and recycle within an among ecosystems Thermodynamic law Energy transfer from one trophic level to the next is quite inefficient Explain how decomposition connects all trophic levels in an ecosystem They recycle all decomposing dead stuff releasing the remaing nutriend back to the earth Producers Primary consumers and secondary consumers are all decomposed after they die and nutrients put back onto the earth 412 How does energy ow through communities Explain why energy is said to ow rather than cycle within ecosystems The energy initial sunlight ows from sun to producers then from producers to various levels of consumers De ne primary production Primary production the energy stored and made available to others by photosynthetic organisms Distinguish between food chains and food webs Food Chain is used to illustrate who feeds on whom in a community It is common to identify A REPRESENTATIVE of each trophic level that eats a representative of the level below it Food web shows many interconnection food chains and more accurately describes the ACTUAL feeding relationships within a given community Describe the various trophic roles and levels including 0 Primary producers 7 1St Trophic Level Primary consumers 7 2quotd Trophic Level Secondary consumers 3rd Trophic Level Tertiary consumers 7 4 Trophic Level will be carnivorous Herbivores 7 Plant Eaters Camivores 7 Meat eaters OOOOO Explain how energy is transferred through trophic levels and describe the 10 rule The transfer of energy between trophic levels is roughly 10 ef cient The energy stored in primary consumers herbivores is only about 10 of the energy stored in the bodies of producers primary consumers predator in turn the bodies of secondary consumers possess roughly 10 of the energy stored in Tertiary consumers For every 100 calories of grass consumed by the primary consumers at the end only 1 calorie remains Chapter Learning Objectives Chapter 39 Population Growth and Regulation De ne ecology and population Ecologythe study of interrelationships between living things and their nonliving environment Population consists of all the members of a particular species that live within an ecosystem and can potentially interbreed Other de nitions Abiotic nonliving component of the ecosystem Ex soil water and weather Biotic Living component of the ecosystem all forms of life Ecosystem Refers to both abiotic and biotic components within a de ned area such as the eastern forest Community organisms that interact within an Ecosystem 391 How does population size change 3 things Births Deaths and migration Being more speci c Causes of population Increases Immigration and Births Causes of population Decrease Emigration and Death Change in population size birthsdeaths immigrants emigrants Distinguish between biotic potential and environmental resistance Biotic potential The maximum rate at which the population could increase ASSUMING ideal conditions that allow a max birth rate and minimum death rate Enviromental resistance imposed by the availability of food and space competition with other organisms and certain interactions among species Darwin theory predation and parasitism Describe the variables involved in the exponential model of population growth Growth rate r the measure of the change in population size per individual per unit of time Birth rate b 7 amount of birthsin one year divided by original population Death rate d amount of deaths in one year divided by original population R boriginal pop 7 d original population J shaped curve shows exponential growth Next years population grows which creates exponential growth This model also allows us to calculate the doubling time of a population based on its current growth rate 392 How is population growth regulated Compare the exponential model of population growth with the Scurve model of population growth J curve Exponential growth faster growth and rapid Only occurs under special circumstances and for a limited time S curve After exponential begins to level off the population usually remains relatively constant uctuating around the carrying capacity of the ecosystem Explain how an environment s carrying capcity affects the per capita rate of increase of apopulation Because the Carrying Capacity is the maximum population size that an ecosystem can sustain and it is determined PRIMARILY by the CONTINUOUS availability of Renewable and nonrenewable resources When overcrowding occurs the weak usually have to compete for resources and die This lowers the population then raises again once resources become optimal to reproduce Explain how densitydependent factors affect population growth Densitydependent factors is a form of environmental resistance that limit population size when population increases For example when population occurs to be over the carrying capacity in an ecosystem food becomes scarce and so does space Meaning those that are prey are easier spotted and is more advantageous for predators to enter Become more effective as population increases Densityindependent factors These are natural events that limit population regardless the size These include hurricanes typhoons frigid winters etc Explain with examples how biotic and abiotic factors may work to control a population s growth Abiotic factors come into play in the control of the population because it is a density independentdependent factor Abiotic is the weather but is also dependent because with overcrowding causes the soil to be less fertile less water available etc austrailia and the prickly pear Biotic is a density dependent living things get overcrowded which can create an environment to be more advantageous to have less food less space and create both PREDATION and PARASITISM Predation when one organism the predator kills another its prey in order to eat it Parasitism When one organism the parasite lives on another its host usually a much larger organism and feeds on the host s body without killing it at least not immediately Describe boomandbust population cycles A boom and bust cycle is when a population exemplifies exponential growth in a very short period of time and because it grows so fast the death rate also is very fast An example would be lemmings who come in the millions in one area and eventually become prey or fall into the ocean exhibiting Darwin s theory Usually short lived rapidly reproductive species Describe the characteristics of populations that exhibit early loss constant loss and late loss survivorship curves Early loss apart of the Survivorship curves produces a concave curve and is characteristic of organisms that produce large numbers of offspring and have a very high early death rate but those that survive usually live a very long time Such as sh most plants and most invertebrates Constant Loss Species that have a relatively constant death rate These species have an equal chance to die at anytime in their life Usually seen in some birds and organisms that reproduce asexually such as bacteria Late Loss Produces a Convex survivorship curve have a relatively low juvenile death rate most individuals survive to old age An example would be Humans 393 How is the human population changing Describe the history of human population growth From the primitive people humans have been able to gradually create technology to ght environmental resistence from re to levy s humans are the only species to be able to resist the environment Stone age was the technical and cultural revolution then in about 8000 bc was the agricultural revolution which allowed better was to get the most out of farming space All these created booms in population although a temporary decline in the 1700 s for the bubonic plague then came where our population has been steadily to exponential growth Because of medicine that can ght disease better homes etc we have been growing incredibly quick from the industrial and medical advances revolutions Compare the age structures for countries with expanding stable and shrinking populations Developing populations There are so many more youth meaning that they will reproduce and greatly exponentially grow faster then other contries Stable Contries have more prereproductive reproductive population and relatively the same post reproductive because they are more educated in contraception and are reproducing a lot less then developing countries Shrinking Populations Such as Europe it is because of emigrations and that less and less reproduction that creates a lot older generation and in the future less children will survive and be able to reproduce
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