Unit 5 BIO 1050
15) model the scientific process of posing, testing, and rejecting hypotheses (1.8 1.9)
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14) describe the perturbations caused by invasive mussel species in the great lakes ecosystem (37.13)
adult zebra mussels attach themselves to any available object, forming thick layers that clog pipes and the water intakes of cities, power plants, and factories. populations of native mussels have declined as a result of competition with zebra mussels for food and space. they disrupt food webs by consuming vast quantities of phytoplankton.
8)describe ecosystems and the roles of chemical cycling, energy flow and the organisms in ecosystems (37.14)
an ecosystem consists of all the organisms in a community as well as the abiotic environment with which the organisms interact. ecosystem ecologists are especially interested in energy flow, the passage of energy through the components of the ecosystem. energy enters as a form of sunlight and plants (producers) convert light energy to chemical energy through the process of photosynthesis. animals (consumers) take in some of this chemical energy, which is stored in organic compounds, when they eat plants. decomposers (bacteria and fungi in soil) obtain chemical energy when they decompose the dead remains of plants and animals. every use of chemical energy by organisms involves a loss of some energy to the surroundings in the form of heat. both energy flow and chemical cycling involve the transfer of substances through the trophic levels of the ecosystem. however, energy flows through, ultimately out of , the ecosystems, whereas, matter is recycled within ecosystems.
1) describe the different reproductive barriers with examples (14.3)
the reproductive barriers keep species separated from reproducing. the prezygotic barriers isolate the species from each other. the prezygotic barriers include habitat, temporal, behavioral, and mechanical. the habitat barrier does not allow 2 species to breed because they live in different habitats. lack of opportunities to encounter each other. the temporal barrier does not allow 2 species to breed because they breed at different times are seasons. the behavioral barrier does not allow 2 species to breed because of their failure to send or receive appropriate signals. the mechanical barrier does not allow 2 species to breed because of their physical incompatibility to reproductive parts.
10)describe carbon cycling, as an example of chemical cycling (37.18 37.19 6.1)
because chemical cycles in an ecosystem include both biotic and abiotic components, they are called biogeochemical cycles. abiotic reservoirs are where chemicals accumulate or are stockpiled outside of living organisms. producers incorporate chemicals from the abiotic reservoir into organic compounds. consumers feed on the producers incorporating some of the chemicals into their own bodies. both producers and consumers release some chemicals back to the environment in waste products (CO2 and nitrogenous waste of animals). decomposers play a central role by breaking down the complex organic molecules in detritus such as plant litter, animal wastes, and dead organisms. photosynthesis and cellular respiration are mainly responsible for the cycling of carbon between the biotic and abiotic worlds. photosynthesis removes CO2 from the atmosphere and incorporates it into organic molecules which are passed along the food chain by consumers. cellular respiration by producers and consumers returns CO2 to the atmosphere. decomposers break down the carbon compound in detritus.
2) describe the history of how humans have changed allele frequencies to meet our own needs (31.1)
because plants undergo physical changes as they are genetically altered by human selection, domestication leaves measurable signs. for example, wild and domestic wheat varieties can be distinguished by several changes in plant anatomy (the seeds are attached to the stalk). the data indicate that before about 10,000 years ago, all wheat found in human settlements was from wild varieties. around 10,000 years ago, wild wheat began to be replaced by domesticated varieties and today, almost all the wheat is of the domesticated variety. microscopic analysis of the size and distribution of amyloplasts, plant cellular organelles that store starch, can sometimes distinguish the difference between wild and domestic varieties. genetic analysis can be used to pinpoint the time and place of domestication. several genes are known to have undergone mutations as a wild species called teosinte was domesticated into modern corn. these genes affect traits that distinguish wild and domestic varieties. (kind of a mix of artificial and natural selection)Domestication implies plants under cultivation that have undergone actual genetic changes resulting from human selection or by adaptations by the plant to the human-manipulated environment. This is a form of genetic engineering, and at first, it probably resulted from people harvesting and ultimately selecting the seeds from particularly desirable wild plant specimens, such as those with larger seeds, bigger fruit, thinner seed coat, or more edible rind. Over time, this selection resulted in increasing the stands of plants with the desirable characteristics. The difference between the wild and domesticated versions of plants like sunflower and marshelder, for instance, reflect an increase in seed size. Domesticated goosefoot displays a small seed similar to wild varieties but a thinner seed coat and other morphological changes. When archaeologists see such changes in the seeds recovered from archaeological sites, they know that people are deliberately growing and harvesting these plants.
7) describe soil conservation and management and how organic farming and genetic engineering play a role (32.9 32.10 32.11)
determining whether a plant can grow well in a particular location is the quality of soil. fertile soil supports plant growth and provides conditions that enable plant roots to absorb adequate amounts of water and dissolved nutrients. the topsoil is a mixture of rock particles of various sizes, living organisms, humus, the remains of partially decayed organic material produced by the decomposition of dead organisms, feces, fallen leaves, and other organic matter. the rock particles in topsoil provide a large surface area that retains water and inorganic ions while also forming air spaces contains oxygen that can diffuse into plant roots. nearly all plants depend on the bacteria and fungi in soil to break down organic matter into inorganic ions that roots can absorb. the cation exchange is a mechanism by which root hairs take up certain positively charged ions. this helps prevent positively charged nutrients from draining away during heavy rain or irrigation. 3 critical goals of soil conservation are proper irrigation , prevention of erosion, and prudent fertilization. fertilizers are used to to enrich the soil with nitrogen, phosphorus, and potassium. organic farming involves agricultural practices that promote biological diversity b y maintaining soil quality through natural methods, which avoids GMOs. the ultimate aim of many organic farmers is to restore as much to the sail as is drawn from it. however, labels are not always true
9)describe the trophic structure, energy budgets, food chains and their energy supply limits (37.8 37.9 37.15 37.16 37.17)
every community has a trophic structure, a pattern o feeding relationships consisting of several different levels. the sequence of food transfer up the trophic levels is known as a food chain. this transfer of food moves chemical nutrients and energy from organism to organism up through the trophic levels in a community. starting at the bottom, the trophic level that supports all others consists of autotrophs (self feeders) called producers. producers use light energy to power the synthesis of organic compounds. all organisms in trophic levels above the producers are heterotrophs, or consumers. herbivores which eat plants, algae, or phytoplankton are primary consumers. carnivores are secondary consumers that eat primary consumers . the third level is tertiary consumers eat secondary consumers. decomposers mainly prokaryotes and fungi secrete enzymes that digest molecules. of the visible light that reaches plants, algae, and cyanobacteria, only about 1% is used for primary production. 15% of the organic material the caterpillar consumed-can be converted to caterpillar biomass. in this idealized pyramid, 10% of the energy available at each trophic level becomes incorporated into the next higher level.
13)list limits factors to freshwater algae growth (34.7 37.20 37.22)
phosphorus and nitrogen increase the growth of primary producers (algae). standing water ecosystem accumulate nutrients from the decomposition of organic matter and fresh influx from the land. primary production increases over time. rapid growth actually slows biodiversity. algae can form massive mats on top of water the prevents light from penetrating the water. other ecosystems are overrun by these and they greatly reduce the oxygen.
6) describe where the matter that makes up plants comes from (7.4 32.6 32.7 32.8)
photosynthesis takes carbon dioxide and water and turns it into glucose and oxygen. plants rely on CO2 and inorganic substances to survive and grow. CO2 from the air, inorganic substances and water from the soil, synthesize organic compounds is essential to the survival of plants but also humans and other living organisms. a nutrient is considered an essential element if a plant must obtain it form its environment to complete its life cycle. there are 9 essential elements that are called macronutrients. 6 of them are carbon, oxygen, hydrogen, nitrogen, sulfur, and phosphorus make up 99% of the plants dry weight. the quality of the soil and the availability of nutrients strongly affects the health of plants. nitrogen shortage is the most common. fertilizers can be put in the soil to promote the plants growth. organic fertilizers like compost do the same.
5) describe the facts regarding the advantages and disadvantages of genetically modified organisms (GMOs) also consider separately how your values will affect your decisions (12.8 12.9)
GMOs have some advantages. they can increase crop yields, pest resistance, salinity resistance, add nutrients, and pharmaceuticals. however, they have their disadvantages as well. recombinant DNA could create new pathogens. human safety could be at risk. even though they are cheaper and claim to be more nutritious, are they really safe for humans to eat. the environment safety as well, GMO crops that grow by wild species might pass their new genes to them and disturb the ecosystem. labeling is a big concern. not all companies label their GMO food correctly and or lie about it and what was used to genetically modify it.
4) describe the challenges of gene therapy (12.10)
gene therapy is the alteration of a diseased individual's genes for therapeutic purposes. people afflicted with disorders caused by a single defective gene (pleiotropic) might be able to replace or supplement the defective gene by inserting a normal allele into that persons cell. 1- a gene from a healthy person is cloned, converted to an RNA version, and then inserted into the RNA genome of a harmless virus. 2- bone marrow cells are taken from the patient and infected with the recombinant virus. 3- the virus inserts a DNA version of its genome including the normal human gene into the cells DNA. 4- the engineered cells are then injected back into the patient. some of the challenges faced are that the treatment can't be applied to polygenic traited people. it hasn't been proved to be very successful yet. some believe messing with genes would damage the human population. if we try to eliminate genetic defects in our future children by permanently changing our genes, we could harm evolution and genetic variability.
3) describe how genetic engineering works, including 2 vectors (12.6 12.7 12.8)
genetic engineering includes recombinant cells and organisms, vectors, and a transgenic organism. GE usually starts with recombinant cells and organisms can mass produce gene products. by transferring the gene for the desired protein into a bacterium, yeast, or other kinds of cell that is easy to grow in culture, a molecular biologist can produce large quantities of useful proteins that are otherwise difficult to obtain. (bacterial-plasmids available for use of gene cloning vectors and the fact that bacteria can be grown rapidly and cheaply in large tanks. eukaryotic- protein production in same yeast used in making bread and beer; easy to grow; better at synthesizing. mammalian cells- proteins with chains of sugars attached) GE has changed the pharmaceutical industry. using GE to treat, diagnose, and prevent diseases by using vectors to implant in the body. GE is used to genetically modify organisms, organisms that have acquired one or more genes by artificial means. if a gene is transplanted from one organism into another, typically of another species, the recombinant organism is called a transgenic organism. GMOs are supposed to improve food producing, shelf life, pest resistance, nutritional value, salinity resistance, increased crop yields.
11) describe how human disruptions to the carbon cycle are causing climate change (7.4 38.3 38.4)
rising concentrations of greenhouse gasses in the atmosphere, like CO2, methane, and nitrous oxide, resulting from human activities are changing global patterns. more than 90% of the heat trapped by greenhouse gasses is being stored in the ocean. water expands as it warms causing sea level to rise. melting of massive ice sheets of Greenland and Antarctica, as well as, mountain glaciers is also contributing to sea level rise. rising sea levels cause flooding of coastal areas worldwide. precipitation patterns are more extreme. some places experience intense drought while others experience torrential downpours that cause flooding. hurricane intensity is increasing ,fueled by higher sea surface temperatures. burning of fossil fuels, and pollution.
12) illustrate the aquatic food chain in the Great Lakes ecosystem and describe the local importance of aquatic ecology (34.6 34.7)
the aquatic food chain is dependent on the amount of sunlight a specie gets. in lakes and large ponds the communities of plants, algae, and animals are distributed according to the depth of of the water and its distance form shore. rooted plants often inhabit shallow waters near shore. in the ethnic real large populations of microorganisms decompose dead organisms that sink to the bottom.the mineral nutrients nitrogen and phosphorus typically determines the amount of phytoplankton growth in a lake or pond. many lakes and ponds receive large inputs of nitrogen and phosphorus from sewage and runoff form fertilized lawns and farms. the nutrients may produce heavy growth of algae that can reduce light penetration. when the algae die and decompose a pond or lake can suffer severe oxygen depletion, killing fish that are adapted to high oxygen conditions. rivers and streams generally support communities of organisms quite different from those of lakes and ponds. a river or stream changes greatly between its source (a spring or snowmelt) and the point at which it empties into a lake or ocean. near the source the water is usually clear, cold, and oxygen-rich. most of the organisms found here are supported by the photosynthesis of algae attached to rocks or by organic material.