Ecology- The study of the interractions of organisms with their physical environment and with each other and of the results of such interactions.

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Alexandrina Cameron
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1 Topic 4: Ecology communities and ecosystems Ecology- The study of the interractions of organisms with their physical environment and with each other and of the results of such interactions. Ecosystem- The organisms in a community plus the associated abiotic factors with which they interact. population- any group of individuals of one species that occupy a given area at the same time; in genetic terms, an interbreeding group of organisms. community- all the populations of organisms inhabititing a common environment and interacting with one another. Species- a group of organisms that actually interbreed in nature and are reproductively isolated from all other such groups; a taxonomic grouping of anatomically similar individuals. habitat- the place in which individuals of a particualr species can usually be found. Biosphere- the zones of air, land and water at the surface of the earch occupied by living things; hence, all the places in which organisms can live on earth. Food Chain- a sequence of organisms related to one another as prey and predator. Food Web- linked food chains with many brances and interconnections. Trophic level- the series of feeding level producer- plants Primary consumer- organism that eats plants secondary consumer- organism that eats other consumers. Autotroph- an organism that is able to synthesize all needed organic molecules from simple inorganic substances and some energy sources. Heterotroph- an organism that must feed on organic materials fromed by other organisms in order to obtain energy and small building-block molecules; in contrast to autotrophs. Detritivore- organisms that live on dead and discarded organic matter; include large scabengers, smaller animals such as earthwoms and some insects, as well as decomposers. Saprotroph- an organism that feeds on nonliving organic matter. light- the initial energy source for almost all communities. photosynthesis- light energy is converted into chemical energy. Light +H2O +CO2= glucose, oxygen, and H2O.--- light energy is used to split water molecules to produce oxygen, hydrogen, and to produce ATP. ATP and hydrogen are used to fix carbon dioxide to make organic molecules. It can be monitored by the production of oxygen, the uptake of carbon dioxide, or the increase in biomass.

2 respiration- involves the breakdown of organic molecules to release energy stored by photosynthesis. The carbon dioxide fixed by photosynthesis is released by respiration. The energy released during repiration of complex compounds in an organism is used within an organism to do work or is lost as heat. Biomass-total weight of all organisms living in a particular habitat or place. Measuring the increase in biomass gives us a measurement of net productivity- the net profit. As an organism grows its biomass increases. um, cool fact? when energy transformations take place, including those in living organisms, the process is never 100% efficient, commonly being only 10-20%. pyramid of energy- only about 10% of all energy from one organism is passed to the other. What happens to all the other energy?? It is used metabolically and lost as heat. another cool fact- energy enters and leaves an ecosystem, but nutreints must be recycled populations population size- affected by natality, immigration, mortality and emigration. natality and immigration increase it, mortality and emmigration decrease it. exponential growth phase- the growth rate of the population increases markedly over time. It shoots up very rapidly as the number of reproducing individuals increases with each generation. The more you have, the more you get. plateau phase- the population has reached the carrying capacity- that is, the number of individuals that the environment can support under a particular set of conditions. transitional phase between latter phases- the growth rate slows down but there are still fluctuations. Eventually the population will stabilize. carrying capacity- The number of individuals of the population that the environment can support given a particular set of conditions. Random sample- each individual has an equal chance at being picked. capture-mark-release-recapture method- a random sample of organisms from a specific habitat is picked- for example 20 beatles. They are all marked and put back into their environment. A specified time later another sample of beatles are taken, this time 30.You check how many of those are marked. In this case there are 5 To see what the population is using these numbers use the following formula: (N1*N2)/N3 where N1=number initially caught, marked and released N2=total number of individuals caught in the second sample N3=number of marked individuals in the second sample. thus, the population is 20*30/5 which is 300 total beatles.

3 Quadrats- a habitat in which a particular population is found is divided up into quadrants- all equal in size. For example, if you divide the population into 100 quadrants, you then take the population of 10% of the total population- thus, 10 of the quadrants. The population of these is taken and multiplied by 10 to estimate the total population. mean- the total sum of numbers divided by the number of data. mode- the most recurring number in the set of data. median- when all numbers are put in order, the middle number. standard deviation- used to summarise the spread of variables around the mean. 68% of the values fall within one standard deviation of the mean (minus and plus). a small standard deviation indicates that the data is clustered closely around the mean value. A larde sd means a wider spread around the mean. The closer the means and the sd of data the more likely the samples are drawn from a similar (the same) population. 4.3 Evolution Evolution in brief- populations tend to produce more offspring than the environment can support. Part of evolution. Because of this, there is competition for survival- since there is not enough for everybody to go around. All offspring are different in some way, those with the best variations for the environment will survive, and breed, and pass on their traits to their offspring. This is called natural selection- it is how species evolve so that they are best adapted to their environment. Evolution is a response to environmental change- you need new adaptions Define evolution evolution: the process of cumulative change in the heritable characteristics of a population State that populations tend to produce more offspring than the environment can support. sigmoid growth curve: S-shaped graph that shows the population growth through the following phases: lag phase log phase decline/death phase Explain that the consequence of potential overproduction of offspring is a struggle for survival. the more offspring in a population the more competition there is for survival. Some offspring have traits that allow them to have an advantage in obtaining food or hiding from its predator. Natural selection supports favorable traits State that the members of a species show variation Define carrying capacity carrying capacity: maximum number of a species that can be sustainably supported by the environment Explain how sexual reproduction promotes variation in a species. during metaphase 1 of meiosis the homologous chromosomes line up and form independent tetrads

4 independent assortment allows for infinite variation an increased chance of variation is due to crossing over of alleles for a trait mutations also contribute to variations of various traits Explain how natural selection leads to the increased reproduction of individuals with favorable traits. some phenotypes for a trait within a species are more favorable for survival than others nature chooses the favorable form possible causes - camouflage Discuss the theory that species evolve by natural selection. evolution is the change in the heritable characteristics of a population over time. when the gene frequency for a favorable trait changes evolution occurs example: moths before Industrial Revolution peppered moth was light colored to blend with lichen on specific tree bark after the Industrial Revolution pollution created turned the tree bark black and the moths experienced natural selection the gene frequency for dark moths increased the gene frequency for the light moths decreased conveys evolution of a species overcoming harmful environment nature selects the variation that best suits the ecosystem variations dominate species because more of that variation will survive to breed and produce Explain the two examples of evolution in response to environmental change, including multiple antibiotic resistance in bacteria. peppered moth (see above) bacteria bacteria have either ½ cell walls for protection antibiotics usually attack building of a bacteria s cell wall bacteria contain genes in their plasmids for being resistant to specific antibiotics rapid mutation of bacteria allows them to become resistant to specific to antibiotics they were not originally resistant to a change in gene frequency then occurs example of current evolution Human impact Greenhouse effect- Because of increased human activities, the ozone layer is thinning. Gases released into the atmosphere by humans such as chlorofluorocarbons from refrigerators, etc. This reacts with the ozone molecule- the choline molecule that is chipped of chlorofluorocarbons, that is. This is thinning out the ozone layer. One impact this has is that the earth is becoming much hotter- the ice caps are melting and the water level is rising, and the temperatures are rising too. Also there is increased risk of cancer. Increase of human habitat- as the human population continues to grow their habitat is increasing also. As a result many of the earth's forests are being cut down, so that many organisms have no home. etc.

Name: Characteristics of Life and Ecology Guided Notes (PAP)

Name: Characteristics of Life and Ecology Guided Notes (PAP) I. What is Biology? a. Biology is the study of II. The Eight Characteristics of Life a. Organization & the presence of or more cells b. Response