Biology Exam 3 Study Guide
Biology Exam 3 Study Guide Bio 102
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This 33 page Study Guide was uploaded by Alyssa Shriver on Thursday March 31, 2016. The Study Guide belongs to Bio 102 at University of Tennessee - Knoxville taught by Dr. Jeremy Chandler in Spring 2016. Since its upload, it has received 19 views. For similar materials see Introduction to Biology in Biology at University of Tennessee - Knoxville.
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Biology Study Guide 3/3 Lecture What’s a population? o Group of organisms of the same species living in the same geographical location Population Ecology o Multidisciplinary science o Biology o Geography o Meteorology o Mathematics Ecology meshes with and is influenced by: o Genetics o Behavior and physiology o Evolution Nomenclature of data o Independent variable variable that stands alone and is not influenced by other variables o Dependent variable depends on other factors (usually the independent variable) o (Independent variable) causes a change in (dependent variable) and it isn’t possible that (dependent variable) could cause a change in (independent variable) o (Time spent studying) causes a change in (test score) and it isn’t possible that (test score) could cause a change in (time spent studying) Hypothesis testing o If your hypothesis is not supported, you accept the null hypothesis Observational/ Discovery science o In this case taking data and creating a relationship with no set experiment o This type of science usually precedes experimental approaches in Ecology Brood Paratism o Is a form of kleptoparasitism. Brood parasites manipulate the behavior of the host so that the host raises the young of the parasite instead of the host’s own young. Ex. Cuckoo Parasitism rates are variable so the actual relationships are more complex o Picky birds often rely on evidence of cuckoo being around. (sight.. but cuckoos are notoriously sneaky) o Some preliminary evidence relates social calls between affected species (sightings of cuckoos) to increased pickiness in some birds on broods Scientific Experiment o Makes Observations o Research the topic to find out what is already known o Ask a testable question o Turn the question into a hypothesis o Make predictions o Conduct an experiment to test the predictions o Analyze the results to arrive at a conclusion Ecology o Individual level: how an individual organism fares in its surroundings o Population level: a group of individuals of the same species living and interacting in the same region A pack of wolves o Community level: interacting populations of different species Wolves prey on moose Ticks infest moose Moose feed on trees o Ecosystem level: species interacting with other species and the environment Moose eat the trees, changing the vegetation, which in turn changes the landscape for other animals Hot summers reduce the ability of moose to feed, affecting their winter survival Isle Royale, Canada o Track wolves and moose for many years to understand dynamic fluctuations between these populations Population ecology o Distribution pattern Organisms distributed in geographic space Depends on resources and interactions with other members of the population Reflect behaviorally or ecological adaption Clumped Distribution o Highdensity clumps are separated by areas of low abundance o When resources are unevenly distributed across the landscape o Or when social behavior dictates grouping Random Distribution o May allow individuals to maximize their access to resources o Individuals are equally likely to be anywhere within the area Uniform Distribution o Individuals maximize space between them by being uniformly spaced o Results from territorial behavior Population Growth o Difference between the birth rate and the death rate o Influenced by Immigration: movement of individuals into a population Emigration: movement of individuals out of a population o Types of population growth Exponential growth Unrestricted growth of a population increasing at a constant growth rate Logistic growth Starts off fast and then levels off Environmental factors will limit an organism’s ability to reproduce For example, access to habitat: the physical environment where an organism lives and to which it is adapted Today’s Objectives o In absence of technology, what is one way researchers can track large animals? “Genetic dogs,” genetic analysis, and scientific models to assess habitat suitability for bears in an area linking the Greater Yellowstone Ecosystem to the northern U.S Rockies o Explain the difference between independent and dependent variables Independent variable: variable that stands alone and is not influenced by other variable Dependent variable: depends on other factors (usually the independent variable) o Explain brood parasitism and why both accepter and rejecter host birds exist Is a form of kleptoparasitism. Brood parasites manipulate the behavior of the host so that the host raises the young of the parasite instead of the host’s own young. Ex. Cuckoo o Explain the 3 levels of ecology we discussed in class Individual level: how an individual organism fares in its surroundings One wolf Population level: a group of individuals of the same species living and interacting in the same region Pack of wolves Community level Interacting populations of different species o Wolves prey on moose o Ticks infest moose o Moose feed on trees 3/8 Lecture Population Growth o Types of population growth Exponential growth Unrestricted growth of a population increasing at a constant growth rate Logistic growth Starts off fast and then levels off Environmental factors will limit an organism’s ability to reproduce For example, access to habitat: the physical environment where an organism lives and to which it is adapted o Various environmental factors such as food availability and access to habitat limit an organism’s ability to reproduce o Carrying capacity The maximum number of individuals that an environment can support given its space and resources Upper limit on the size of any population o Size of a population may fluctuate around the environment’s carrying capacity o Disease or food shortage cause population to shrink o Allows environment time to recover its food supply o Population may begin to grow again o Boom and bust Liebig’s Law of the minimum o Growth rate is limited by a single limiting resource Patterns of population growth o Anything that affects the size of one population could affect the size of other populations in the ecosystem as well o Isle Royale Population Health o Ecologists use a variety of data to monitor the health of populations Population Density o Isle Royale: a number of factors influence the likelihood that wolves will kill moose o Definition of population density Number of organisms per given area o Densitydependent factors A factor whose influence on population size and growth depends on the number and crowding of individuals in the population Such as predation o Densityindependent factors A factor that influences population size and growth regardless of the numbers and crowding within a population Such as weather Population Control Mechanisms o Other factors affecting population size Disease Canine parvovirus Climate Change Less eating in warm weather Warm weather favors ticks Ecology o Community level: interacting populations of different species Wolves prey on moose Ticks infest moose Moose feed on trees Herbivore Enclosures o Longterm impacts of deer browsing o Changes for forest composition o Lower productivity and diversity Ecosystem Engineers o An organism that modifies, creates or destroys habitat and directly or indirectly modulates the availability of resources to other species, causing physical state changes in biotic or abiotic materials What’s happening to Honey Bees? o CCDColony collapse disorder o 3040% of keepers’ bees are lost every year since 2006 o Silence of the Bees documentary posted to BB. Role of Bees o Bees are pollinators o Associated with evolution of flowering plants o Pollen Small, thickwalled plant structures that contain cells that develop into sperm o Pollination Transfer of pollen from male to female plant structures so that fertilization can occur o Without honey bees, we wouldn’t starve we would still have wheat, rice, corn, and other crops that are either wind or selfpollinated but many of our favorite foods might no longer grace our table Community Ecology o 75% of flowering plants, or angiosperms, are dependent on insect pollinators o Keystone Species Species on which other species depend; hold community together o Community Group of interacting populations of different species living together in the same area Reproductive structures of flowering plants o Male reproductive organ Stamen: stemlike filament topped with a pollensaturated anther o Female reproductive organ Pistil: topped with a sticky “landing pad” (stigma) Style: a tubelike passage from stigma to the ovary Pollinators o Fertilized egg develops into an embryocontaining seed o Surrounding ovary becomes the fruit Food Chains o Linked sequences of feeding relationships in a community o Organisms categorized by who eats whom Producers: autotrophs that supply energy to rest of food chain Consumers: heterotrophs that eat producers Predators: one organism feeds on the other (prey) Herbivores: predation on plants, which may or may not kill the plant Trophic Levels o In a food chain, energy flows in one direction: from producers to consumers. Producers obtain energy from the sun. Consumers obtain energy by eating producers. As consumers eat other consumers, the flow of energy continues up the food chain. The passage of energy is not efficient, however, as only 10% of energy makes it from one trophic level to the next. The result is an energy pyramid Producers like blueberry bushes obtain energy from the sun Only 10% of the total energy form an organism is passed to the next organism in the chain Consumers like mice and hawks obtain energy by feeding on other organisms 90% of energy is lost to metabolism, heat, and waster between each trophic level o The intersection of multiple food chains in a community results in a complex food web. Individual organisms in the food web have multiple important roles that keep the community healthy Symbiotic Relationships o Symbiosis: relationship in which two different organisms live together, often interdependently Parasitism Mutualism Commensalism o Parasitism: symbiotic relationship in which one member benefits at the expense of the other Toxoplasma gondii o A protozoan parasite that infects most species of warm blooded animals, including humans, and can cause the disease toxoplasmosis “Mind Control” by Microbes o In the human host, the parasites form tissue cysts, most commonly in skeletal muscle, myocardium, brain, and eyes; these cysts may remain throughout the life of the host Today’s Objectives o Explain Liebig’s law of the minimum Grow rate is limited by a single limiting resource. Resources can be habitat, nutrients or a plethora of many things. If one resource is limited the growth rate will slow o Explain how we measure population growth and how we know when carrying capacity has been reached Calculated by subtracting death rate from the birth rate Carrying capacity has been reached when a given amount of recourses can only support a defined number of species o Explain how cascades set in motion from both direct and indirect ecosystem engineers can affect physical environments Trophic cascades in ecological communities are defined as the propagation of indirect effects between nonadjacent trophic levels in a food chain or food web. Typically, cascades are driven by predation from the topdown, with altered herbivore densities mediating the ultimate effects on the biomass of primary producers. Predator traits and nonconsumptive changes in the behavior of prey can propagate cascading indirect effects, and variation in nutrients or energy at the base of food webs may mediate cascades from the bottomup. When a predator in a food web suppresses the abundance of its prey, thereby releasing the next trophic level from predation. o Explain the role of bees and why they are considered as keystone species Bees are pollinators and associated with evolution of flowering plants. Bees play a fundamental role in supporting the entire community. While bees may not be the most abundant member of the community, their loss has a huge impact on the community and the ecosystem o Explain the basis of trophic energy flow in food webs Energy flows in multiple directions. Producers get their energy from the sun. The consumers get their energy from the producers or other consumers. o Explain what a symbiosis is A relationship in which two different organisms live together, often interdependently 3/10 Lecture Interspecific Interactions o Interactions between species o Can be classified according to the effect on the populations concerned / interactions occur when two populations in a community compete for a common resource +/+ interactions are mutually beneficial, such as between plants and their pollinators +/ interactions occur when one population benefits and the other is harmed, such as in predation Symbiotic Relationships o Symbiosis: relationship in which two different organisms live together, often interdependently Parasitism (+/) Mutualism (+/+) Commensalism (+/0) o Parasitism: symbiotic relationship in which one member benefits at the expense of the other o Mutualism: symbiotic relationship in which both members benefit o Commensalism: symbiotic relationship in which one member benefits and the other is unharmed Toxoplasma gondii o Protozoan parasite that infects most species of warm blooded animals, including humans, and can cause the disease toxoplasmosis “Mind Control” by Microbes o In the human host, the parasites form tissue cysts, most commonly in skeletal muscle, myocardium, brain, and eyes; these cysts may remain throughout the life of the host Lichen o Algae or cyanobacteria living among filaments of a fungus in a symbiotic relationship o Lichen Structure Lichen Members o Fungi Protects the photobiont from exposure to intense sunlight and desiccation To absorb mineral nutrients from the underlying surface or from minute traces of atmospheric contaminants (heterotrophs) o Cyanobacteria/Algae Synthesize organic nutrients from carbon dioxide (autotrophs) In case of some cyanobacteria also fix nitrogen Obesity and gut microbiota o Evidence suggests that obese and lean organisms have different gut microbiota o Gut microbiota has been shown to affect fat storage and energy harvesting which suggests that intestinal microorganisms may play a direct role in the development of obesity o The intestine’s microbial population is complex but balanced Antibiotic therapy disrupts this balance and may lead to poor digestion or disease Ex. Pseudomembranous colitis, which is caused by Clostridium difficile o Probiotics are living microbes that are ingested to restore the natural microbial balance The most commonly used genera are Bifidobacterium and Lactobacillus Clostridium difficile o C.diff soil borne gram positive spore forming bacteria that have optimum growth potential at human body temperature Spores survive harsh acidic conditions and allow the organisms to colonize the colon Can secrete enterotoxins which cause severe diarrhea and inflammation Easily spreads in hospital situations and have high characteristic resistance to antibitoics Gut Microbiota have effects in other species too o Vulture gut microbes help them to eat flesh loaded with toxic bacteria and spores that would kill us Commensalism? o Many of the normal flora, like Staphylococcus epidermidis of larger organisms neither hurt nor help their hosts The ecological Niche o The space, environmental conditions, and resources that species need in order to survive and reproduce A population growing at a constant rate without checks will increase exponentially. However, for most populations found in nature, as the population reaches its carrying capacity, the growth rate slows and eventually remains at or near zero Competing for resources o If niches overlap Two or more species rely on same limited resources Result is competition o Competitive exclusion principle One of the competing species will be driven to extinction o Species with similar niches compete for resources that may be limited because of natural or human influences. Species may outcompete one another or find a balance, depending on their foraging abilities and behaviors Deception, Lies and Defense in Nature o Organisms have evolved very special ways to deal with both predation and herbivory in their specific niches Cryptic Coloration o Camouflage o Prey species can evolve in response to predation pressures o Predators may also evolve these features Warning Coloration o A warning coloration is A brightly colored pattern and A way to warn predators that an animal has an effective chemical defense Mimicry o A form of defense in which one species looks like another species Herbivory Defenses o Plants have evolved numerous defenses against herbivory, including Spines, Thorns, and Chemical toxins Today’s Objectives o Explain how to classify different interspecific interactions. Interspecific interactions can be classified according to the effect on the populations concerned. o Explain some effects of parasitic and symbiotic microbes with their hosts. Lichen protects the photobiont from exposure to intense sunlight and desiccation. Also absorbs mineral nutrients from the underlying surface or from minute traces of atmospheric contaminants. Cyanobacteria/ Algae synthesize organic nutrients from carbon dioxide and cyanobacteria also fix nitrogen. o Explain how C. difficile infections often occur and how a fecal transplant works to combat them. Occur due to the soil borne gram positive spore forming bacteria that have optimum growth potential at human body temperature. Spores survive harsh acidic conditions and allow the organisms to colonize the colon. It can secrete enterotoxins which cause severe diarrhea and inflammation. A fecal transplant can combat them by flushing out the enterotoxins. o Explain how relationships between organisms can be hard to classify. A relationship could have multiple types of relationships or also change over time. o Explain some strategies organisms might to alleviate the chance that they might be competitively excluded. Food portioning is when a species specializes on one food that another species can’t efficiently utilize Generalist foraging patterns Defensive behavior is when a species uses an aggressive defense of food resources. Ex. Chasing other species away from the available food source o Explain how coloration could be used by organisms in their environments. Mimicry is when a species looks like another species Ex. Sphinx moth larva Warning Coloration is when a species warns predators that an animal has an effective chemical defense Ex. Skunk Cryptic coloration is when a species can use camouflage is response to predation pressures Ex. Seahorse on coral o Explain some mechanisms plants have evolved to defend against herbivory. Spines, thorns and chemical toxins 3/22 Lecture Ecosystem Biotic Trophic Structures o Primary consumers are called herbivores, which eat plants o Above the level of primary consumers are carnivores, which eat the consumers from the level below Secondary consumers eat primary consumers Tertiary consumers eat secondary consumers Quaternary consumers eat tertiary consumers Ecosystem o Complex, interwoven system of interacting components o Includes both community of living organisms and features of the nonliving environment o Biotic and abiotic parts o Dynamic systems A Hierarchy of Interactions o Many different factors can potentially affect an organism’s interaction with the environment Biotic factors are All of the organisms in the area and The living component of the environment Abiotic factors Are the environment’s nonliving component and Include chemical and physical factors, such as temperature, light, water, minerals, and air Environmental Variability o The abiotic factors in a habitat may vary From year to year Seasonally, or Over the course of a day Temperature o Temperature affects metabolism Few organisms can maintain a sufficiently active metabolism at temperatures close to 0 degrees C Temperatures above 45 degrees C destroy the enzymes of most organisms o Most organisms function best within a specific range of environmental temperatures Physiological Responses o Acclimation is Gradual, Reversible, and A physiological adjustment to an environmental change o The ability to acclimate is generally related to the range of environmental conditions a species naturally experiences o Among vertebrates, Birds and mammals can tolerate the greatest temperature extremes because they are endotherms, while Ectothermic reptiles can only tolerate a more limited range of temperatures Adjusting to Environmental Variability o Birds may adjust to cold by Migrating to warmer regions (a behavioral response), Growing heavier feathers (an anatomical response), or Fluffing up their feathers to trap more heat (a physiological response) Anatomical Responses o Many organisms respond to environmental challenges with some type of change in Body shape and Structure o Reversible change, such as a heavier fur coat in response to cold, is an example of acclimation Water o Water is essential to all life o For terrestrial organisms, the main water problem is drying out o Aquatic organisms Are surrounded by water and Face problems of water balance if their own solute concentration does not match that of their surroundings Inorganic Nutrients o The distribution and abundance of plants are often determined by the Availability of inorganic nutrients such as nitrogen and phosphorus and The structure, pH and nutrient content of the soil o In many aquatic ecosystems, the growth of algae, photosynthetic bacteria, and heterotrophic bacteria is often limited by levels of Nitrogen and Phosphorus Other Aquatic Factors o Aquatic but not terrestrial ecosystems are more limited by The levels of dissolved oxygen, Salinity, Currents, and Tides Other Terrestrial Factors o Terrestrial but not aquatic ecosystems are more limited by Wind, Storms, or Fire Fire Fighting o Forestry service adopted policy of suppression of all forest fires o Led to backlog of flammable tinder materials, which is largely thought to have led to the modern day mega wildfires we are experiencing o $ 3,500,000,000/ year to fight fires Disturbance o Disturbance disturbance alters the chemical or organismal components of an ecosystem o Disturbance is a normal part of some ecosystems Disturbances in Communities o Disturbances are episodes that damage biological communities, at least temporarily, by Destroying organisms and Altering the availability of resources such as mineral nutrients and water Disturbances in Communities and Ecosystems o Disturbances may cause The emergence of a previously unknown disease Opportunities for other organisms to grow Ecological Succession o Disturbances may cause a gradual replacement by other species in a process called ecological succession o Primary succession begins In a virtually lifeless area with no soil, In place such as The rubble left by a retreating glacier or Lava flows Ecological Succession o Secondary succession occurs where a disturbance has Destroyed an existing community but Left the soil intact o Examples of secondary succession are areas recovering from Floods or Fires Ecosystem Ecology o Energy flow Is the passage of energy through the components of the ecosystem Flows through and is ultimately lost o Chemical cycling Is the use and reuse of chemical elements such as carbon and nitrogen within the ecosystem Recycled within and between ecosystems o Each day, Earth receives about 10^19 kcal of solar energy. o Most is absorbed, scattered, or reflected by the atmosphere or surface of Earth Primary Production o The amount, or mass, of living organic material in an ecosystem is the biomass o The rate at which an ecosystem’s producers convert solar energy to the chemical energy stored in biomass Is primary production Yields about 165 billion tons of biomass per year o Different ecosystems vary considerably in their primary production Today’s Objectives o Explain how energy gets from the sun into a snake The snake (tertiary consumers) consume secondary consumers. The secondary consumers consume primary consumers who consume producers. Producers get their nutrients from the sun. o Be able to interpret map range data and come up with hypotheses around factors that might influence populations o Compare and contrast adaptation vs. acclimation processes in organisms Acclimation is gradual, reversible and a physiological adjustment to an environmental change. Ex. Birds and mammals can tolerate the greatest temperature extremes because they are endotherms, while ectothermic reptiles can only tolerate a more limited range of temperatures Adaption refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation Ex. Birds may adjust to cold by migrating to warmer regions, grow heavier feathers or fluffing up their feathers to trap more heat o Explain the limitations in aquatic vs. terrestrial biomes Aquatic but not terrestrial ecosystems are more limited by the levels of dissolves oxygen, salinity, currents and tides Terrestrial but not aquatic ecosystems are more limited by wind, storms, or fire o Explain scenarios where disturbance could be good or bad for the functioning of an ecosystem Tree falling in a forest can provide more homes for other organisms o Explain the different levels of ecological succession Primary succession beings In a virtually lifeless area with no soil In places such as o The rubble left by a retreating glacier or o Lava flow Secondary succession occurs where a disturbance has Destroyed an existing community but Left the soil intact Ex. Floods or fires o Explain the differences between energy flow and chemical cycling in an ecosystem Energy flow is the passage of energy through the components of the ecosystem Flows through and is ultimately lost Chemical cycling is the use and reuse of chemical elements such as carbon and nitrogen within the ecosystem Recycled within and between ecosystems Lecture 3/24 Photosynthetic microorganisms contribute about 50% of Earth’s primary productivity Biomes o A biome is A major terrestrial or aquatic life zone, Characterized by Vegetation type in terrestrial biomes or The physical environment in aquatic biomes o Aquatic biomes Occupy roughly 75% of Earth’s surface and Are determined by their Salinity and Other physical factors o Freshwater biomes Have a salt concentration of less than 1% and Include lakes, streams, rivers, and wetlands o Marine biomes Typically have a salt concentration around 3% and Include oceans, intertidal zones, coral reefs, and estuaries Freshwater Biomes o Freshwater biomes Cover less than 1% of Earth, Contain a mere 0.01% of its water, Harbor about 6% of all described species Are used of Drinking water Crop irrigation Sanitation, and Industry Freshwater biomes fall into two broad groups: Standing water includes lakes and ponds Flowing water such as rivers and streams Aquatic Biome portioning of life o In aquatic biomes, the communities of plants, algae, and animals are distributed according to the Depth of water and Distance from shore Aquatic Life Zones o The photic zone, named because light is available for photosynthesis, includes The shallow water near shore and The upper layer of water away from shore o The aphotic zone Is deeper and Has light levels too low to support photosynthesis o The benthic realm is At the bottom of all aquatic biomes, Made up of sand and organic and inorganic sediments, and Occupied by communities of organisms that are collectively called benthos Roles of nutrients in aquatic biomes o The amount of phytoplankton growth aquatic environments is typically regulated by the nutrients available Nitrogen and Phosphorus Rivers and Streams o Rivers and streams Are bodies of water flowing in one direction and Generally support quite different communities of organisms than lakes and ponds o Source Streams Cold Clear Swift Lower Nutrients o Downstream Warmer Turbid Slow High Nutrients Biomes o Aquatic: marine o Aquatic: freshwater o Tropical forest o Temperature forest o Grassland o Desert o Taiga o Tundra Terrestrial Biomes o Terrestrial ecosystems are grouped into biomes primarily on the basis of their vegetation type o A climograph is a visual representation of the differences in Precipitation and Temperature ranges that characterize terrestrial biomes The effect of climate on biome distribution o Heated by the direct rays of the sun, air at the equator Rises, Then cools, forming clouds, and Drops rain o This largely explains why rain forests are concentrated in the tropics, the region from the Tropic of Cancer to the Tropic of Capricorn Chemical cycling in ecosystems o All life depends on recycling of chemicals o Nutrients acquired are ultimately released by a waste by living organisms o Death nutrients and chemicals that make up organisms are returned to the environment through decomposers Biogeochemical cycling o Biogeochemical cycles involve Biotic components and Abiotic components from an abiotic reservoir where a chemical accumulates or is stockpiled outside of living organisms o Biogeochemical cycles can be: Local or Global o Three important biogeochemical cycles are: Carbon Phosphorus and Nitrogen The Carbon Cycle o Carbon, the major ingredient of all organic molecules, Has an atmospheric reservoir and Cycles globally o The cycling of carbon between the biotic and abiotic worlds is accomplished mainly by the reciprocal metabolic processes of Photosynthesis and Cellular respiration The Phosphorus Cycle o Organisms require phosphorus as an ingredient of Nucleic acids, Phospholipids, and ATP o Phosphorus is also required as a mineral component of vertebrate bones and teeth o The phosphorus cycle does not have an atmospheric component The Nitrogen Cycle o Nitrogen is An ingredient of proteins and nucleic acids and Essential to the structure and functioning of all organisms o Nitrogen has two abiotic reservoirs The atmosphere and The soil o The process of nitrogen fixation converts gaseous N2 to nitrogen compounds that plants can assimilate o Most of the nitrogen available in natural ecosystems comes from biological fixation performed by two types of nitrogenfixing bacteria Some bacteria live symbiotically in the roots of certain species of plants, supplying their hosts with a direct source of usable nitrogen Freeliving nitrogenfixing bacteria in soil or water convert N2 to ammonia, which then picks up another H+ to becomes ammonium (NH4+) What is a virus? o A virus is a noncellular particle that must infect a host cell, where it reproduces It typically subverts the cell’s machinery and directs it to produce viral particles o Consist of nucleic acid (DNA or RNA) contained within a protective protein capsid o Viruses share some, but not all, characteristics of living organisms. o Viruses Possess genetic material in the form of nucleic acids wrapped in a protein coat, Are not cellular, and Cannot reproduce on their own Bacteriophages o Bacteriophages, or phages, are viruses that attack bacteria o Phages consist of a molecule of DNA, enclosed within an elaborate structure made of proteins o Phages have two reproductive cycles In the lytic cycles Many copies of the phage are produced within the bacterial cell, and Then the bacterium lyses (breaks open) In the lysogenic cycle, The phage DNA inserts into the bacterial chromosome and The bacterium reproduces normally, copying the phage at each cell division Today’s Objectives o Explain where the majority of primary productivity is derived in aquatic and terrestrial biomes Algal beds, coral reefs, estuary and tropical rain forest o Explain how aquatic and terrestrial biomes are characterized Characterized by Vegetation type in terrestrial biomes or The physical environment in aquatic biomes Aquatic biomes are characterized by Salinity and Other physical factors Terrestrial biomes are characterized by The basis of their vegetation type o Explain the various zones we see in an ocean setting and how they interact in terms of energy flow and nutrient availability The photic zone, named because light is available for photosynthesis, includes The shallow water near shore and The upper layer of water away from shore The aphotic zone Is deeper and Has light levels too low to support photosynthesis The benthic realm is At the bottom of all aquatic biomes, Made up of sand and organic and inorganic sediments, and Occupied by communities of organisms that are collectively called benthos o Explain how by just looking at the picture of the Smokies today you could get a general idea of what expected rainfall in the environment might be like By looking at the picture of the Smokies you can get a general idea of what expected rainfall in the environment might be like because of the amount of rain that fell can dampen the ground. Also you can tell by the humidity of the environment o Explain the 3 important nutrient cycles we discussed today and where their respective reservoirs are Carbon Cycle The major ingredient of all organic molecules o Has an atmospheric reservoir and o Cycles globally The cycling of carbon between the biotic and abiotic worlds is accomplished mainly by the reciprocal metabolic processes of o Photosynthesis and o Cellular respiration The Phosphorus Cycle Organisms require phosphorus as an ingredient of o Nucleic acids, o Phospholipids and o ATP Phosphorus is also required as a mineral component of vertebrate bones and teeth The phosphorus cycle does not have an atmospheric component The Nitrogen Cycle Nitrogen is o An ingredient of proteins and nucleic acids and o Essential to the structure and functioning of all organisms Nitrogen has two abiotic reservoirs: o The atmosphere and o The soil o Explain why a virus is non living but might be considered by some as living A virus is a noncellular particle that must infect a host cell, where it reproduces It typically subverts the cell’s machinery and directs it to produce viral particles Consist of nucleic acid (DNA or RNA) contained within a protective protein capsid Possess genetic material in the form of nucleic acids wrapped in a protein coat, Are not cellular, and Cannot reproduce on their own o Explain the lytic and lysogenic cycles in bacteriophages In the lytic cycle, Many copies of the phage are produced within the bacterial cell, and Then the bacterium lyses (breaks open) In the lysogenic cycle The phage DNA inserts into the bacterial chromosome and The bacterium reproduces normally, copying the phage at each cell division 3/29 Lecture Nutrient Pollution o The growth of algae and cyanobacteria in aquatic ecosystems is limited by low nutrient levels, especially Phosphorus and Nitrogen o Nutrient pollution occurs when human activities ass excess amounts of these chemicals to aquatic ecosystems o Nitrogen runoff from Midwestern farm fields has been linked to an annual summer “dead zone” in the Gulf of Mexico Eutrophication o Enrichment of an ecosystem with chemical nutrients, typically compounds containing nitrogen, phosphorus, or both o Can cause Reduction in oxygen in water Algal blooms that secrete toxins, which foul water supplies Algal “bust” after bloom leads to mass nutrients releases Humans are very similar o Homo sapiens: biological species of humans o Highly similar to one another How do we examine genetic code? o Build a representative library of genetic code for species we have collected o Compare and contrast similarities and differences between specimens o These comparisons can help us asses relatedness, evolutionary descent and even age of individuals Molecular Clocks o The molecular clock is the temporal information contained in a macromolecular sequence Based on the acquisition of new random mutations in each round of DNA replication Chick Eggs too o An ancient retrovirus is thought to be the reason for characteristic “blue eggs” in some chickens o Cause egg shell to absorb greenblue bile pigment called biliverdin MOP common misconceptions o Human evolution is not a ladder with a series of steps leading directly from an ancestral anthropoid to Homo sapiens This is often illustrated as a parade of fossil hominins (members of the human family) becoming progressively more modern as they march across the page Instead, human evolution is more like a multibranched bush than a ladder At times in hominin history, several different human species coexisted The Human Ancestry o Humans are primates, the mammalian group that also includes Lorises, Pottos, Lemurs, Tarsiers, Monkeys, and Apes Primates o Primates evolved from insecteating mammals during the late Creataceous period, about 65 million years ago o Primates are distinguished by characteristics that were shaped by the demands of living in trees. These characteristics include Limber shoulder joints, Eyes in front of the face, Excellent eyehand coordination, and Extensive parental care Primates 3 Main Groups o The first group of primates includes Lorises, Pottos, and Lemurs o Tarsiers form the second group o The third group, anthropoids, includes Monkeys, apes, the ape relatives of humans, and you Humankind o Humans and chimpanzees have shared a common African ancestry for all but the last 57 million years o Chimpanzees and humans represent two divergent branches of the anthropoid tree that each evolved from a common, less specialized ancestor o Our ancestors were not chimpanzees or any other modern apes Becoming Human o Hominid Any member of the biological family Hominidae Includes living and extinct great apes Humans, orangutans, gorillas, chimpanzees, and bonobos Other Misconceptions o Different human features evolved at different rates o At separate times during human evolution, upright posture and an enlarged brain evolved What are two physical attributes that humans and chimpanzees clearly differ by? o Presentday humans and chimpanzees clearly differ in two major physical features. Humans are… Bipedal and Have much larger brains Today’s Objectives o Explain how eutrophication can lead to dead zones and fish kills. Eutrophication is the enrichment of an ecosystem with chemical nutrients, typically compounds containing nitrogen, phosphorus, or both. Eutrophication over pollutes the environment killing living things by having “too much” of chemical nutrients o Explain the many diverse roles of viruses in biogeochemical cycling as well as in our own genetic makeup. Ocean viruses may turn over as much as 150 gigatons of carbon per year more than 30 times the standing abundance of carbon in marine plankton. Upon infection, the virus causes the cell to relocate molecular machinery and raw materials, such as carbon and other nutrients, toward DNA replication and production of viral structural proteins. In some instances there may be grater uptake of nutrients and/or additional production of host machinery involved in carbon fixation o Explain the molecular clock and the tool that researchers and we used in class to find identities of unknown DNA sequences. The molecular clock is the temporal information contained in a macromolecular sequence. The Basic Local Alignment Search Tool is a program that allows researchers to search and compare DNA, RNA, and protein sequences against known databases for identities of organisms they are interested in o Explain why the march of progress image is not evolutionary representative of our natural history. Human evolution is not a ladder with a series of steps leading directly from an ancestral anthropoid to Homo sapiens This is often illustrated as a parade of fossil hominins becoming progressively more modern as they march across the page Instead, human evolution is more like a multibranched bush than a ladder 3/31/16 Lecture Becoming human o Hominid Any member of the biological family Hominidae o Includes living and extinct great apes Humans, orangutans, gorillas, chimpanzees, and bonobos What are two physical attributes that humans and chimpanzees clearly differ by? o Present day humans and chimpanzees clearly differ in two major physical features. Humans Are bipedal and Have much larger brains Bipedalism o Bipedalism probably evolved first Before there was the genus Homo, several hominin species of the genus Australopithecus walked the African savanna Scientists are now certain that bipedalism is a very old trait Evidence of change o Researchers can turn to microbial fossil records to understand conditions that may have existed in region lakes Becoming human o Ardipithecus ramidus (4.4 million years ago) Small brain Bones show it could walk upright o Australopithecus (2.6 million years ago) Could walk upright Lived on ground Tools Homo Habilis o “handyman” Had a larger brain, intermediate in size between Australopithecus and modern humans, Walked upright, and Made stone tools that enhanced hunting, gathering, and scavenging on the African savanna Homo erectus o 800,000 years ago o Controlled fire o Was the first species to extend humanity’s range from Africa to other continents o The global dispersal began about 1.8 million years ago o Homo erectus Was taller than H. habilis and Had a larger brain Homo neanderthalensis o Homo erectus gave rise to Regionally diverse descendants in Europe and Asia and Homo neanderthalensis, commonly called Neanderthals o Neanderthals And modern humans last shared a common ancestor about 500,000 years ago and Interbred with some Homo sapiens Homo sapiens o Between 200,000 years ago fossil evidence o Oldest DNA 45,000 from Siberian sample o Long childhood development to adult form o Big brains Origin and dispersal of homo sapiens o The oldest known fossil of our own species, Homo sapiens Were discovered in Ethiopia and Date from 160,000 to 195,000 years ago o DNA studies strongly suggest that all living humans can trace their ancestry back to a single African Homo sapiens lineage that began 160,000 to 200,000 years ago Humans evolved in Africa o “Out of Africa” hypothesis is currently the most widely supported theory o Humans originated in Africa o A group migrated to other continents o Additional fossil evidence shows modern humans lived in Africa at time of “mitochondrial Eve” o Perform genetic analysis to confirm common ancestry o Mitochondrial DNA DNA in mitochondria is inherited solely from mothers mtDNA mutates at regular rate mother with a mutation in her mtDNA will pass it to all her children can track human ancestry and build evolutionary tree: “mitochondrial Eve mtEve” o Mitochondrial EVE Is not fixed individual Had a mother Was not the only woman of her time Origin and dispersal of homo sapiens o Fossil evidence suggests that our species emerged from Africa in one or more waves. o The oldest fossils of H. sapiens outside of Africa are 50,000 years old. o The oldest fossils of humans in the New World are uncertain, but are at least 15,000 years old. o Certain uniquely human traits have allowed for the development of human societies. o The primate brain continues to grow after birth and the period of growth is longer for a human than for any other primate. o The extended period of human development lengthens the time for parents to care for their offspring and pass along culture. Three recent lineages can account for much of our genetic diversity o Homo sapiens o neanderthal
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