Chapters 14-16 Notes
Chapters 14-16 Notes 301
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This 8 page Class Notes was uploaded by Morgan Deal on Friday October 30, 2015. The Class Notes belongs to 301 at University of South Carolina taught by Dr. April South in Summer 2015. Since its upload, it has received 26 views. For similar materials see Ecology and Evolution in Biology at University of South Carolina.
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Date Created: 10/30/15
CHAPTER 14 con39t Predation and Herbivory Hunting Strategies 0 Active hunting predator spends most of the time moving around looking for prey o Ambush sit and wait hunting predator lies in wait for prey to pass 0 Hunting is a series of events including detecting pursuing catching handling and consuming prey Prey have evolved defenses to thwart predators Behavioral Defenses Alarm calling warns relatives of approaching predators Spatial avoidance Activity reduction reduce activity to avoid detection Crypsis and Structural Defenses Crypsis camou age Structural defenses reduce predator s ability to capture attack and handle prey Chemical Defenses More effective if prey can convey defense before attack occurs 0 Warning coloration aposematism distastefulness evolves in association with conspicuous colorspatterns of prey o Predators can have innate aversions to aposematic colors or learn from experience 0 Mimicry o Palatable species resembling distasteful species are favored o Batesian mimicry palatable species evolve coloration of unpalatable species 0 Mullerian mimicry several unpalatable species evolve similar warning colorations Costs of Defenses Behavioral defenses are often costly draw attention to prey tradeoffs in resource gathering Mechanical defenses are energetically expensive 0 Costs can reduce growth development and reproduction Defenses Against Herbivores Selective pressure from herbivores has caused evolution of plant defenses 0 Structural sharp spines hair 0 Chemical sticky compoundsresins latex compounds alkaloids caffeine nicotine morphine o Toleration plants that tolerate herbivory have rapid growth and reproductive rates CHAPTER 15 Parasitism and Infectious Diseases Parasites Organisms that live inon another organism host Harm but rarely kill host host needs to be alive for parasite to take its resources Pathogen parasite that causes infectious disease 0 Infection does not always result in disease 0 Infectious disease spreads between individuals 0 About 25 of human deaths due to infectious diseases 0 Emerging infectious disease newly discovered or re emerging infectious disease H5N1 mad cow disease About 1 emerging diseaseyear Ectoparasites Live on the outside of an organism attach to host and consume bodily uids 0 High exposure to natural enemies 0 High exposure to external environment 0 Little difficulty moving from host to host 0 Low exposure to host immune system Organisms o Arthropods eas lice mites ticks o Leeches o Lampreys o Nematodes 0 About 4K plants Hemiparasites parasites that can obtain nutrients by themselves as well as from the host Endoparasites 0 Live on the inside of an organism o lntracellular live on the inside of the cell 0 lntercellular live in between cells and in bodily cavities Low exposure to natural enemies Low exposure to external environment 0 Difficult to move from host to host 0 High exposure to host immune system Organisms o Bacteria fungi viruses Bacteria usually need help from an herbivore to enter plant Ussues Fungi have large ecological impacts destroys many crops 0 Helminths worms 0 Prions proteins found in the brain that fold incorrectly and become pathogenic Causes the formation of more prions when they come in contact with other proteins Fatal Ex Mad cow disease 0 Protozoansmalaria Mechanisms of Parasite Transmission 0 Horizontal transmission parasite moves between individuals that are not parentoffspring 0 Vertical transmission parasite transferred from parent to offspring 0 Host cannot die until it has reproduced to ensure parasite survival 0 Vector organism that disperses parasites between hosts 0 Some parasites require multiple hosts to complete life cycle Parasite and Host Dynamics Cyclical population uctuation Similar to predator and prey dynamics 0 BIG DIFFERENCE parasites don t usually kill their prey and can reproduce faster than other predators 0 Factors in uencing probability of host infection 0 Mechanism of transmission 0 Mode of entering host piercing tissue ecto v vector endo 0 Ability of parasite to jump between species parasites that can infect multiple species have a higher chance of infection and survival 0 Existence of reservoir species host is infected but does not succumb to disease Continuous source of parasites when other hosts become rare Ensure survival of parasites o Counterattacks to host immune system Escape immune system by making itself undetectable Live in cytoplasm or chromosomes immune systems search for infectious outside of cells not inside Change compounds of outer surface to be constantly unrecognizable to immune system Population Fluctuations Density of hosts denser populations help parasites Can be caused by changes in proportion of host infection resistance and tolerance continued infection increases proportion of population developing immunity 0 Infection resistance ability of host to prevent infection from occurring 0 Vaccinations increase resistance 0 Infection tolerance ability of host to minimize harm from infection Modeling Parasite and Host Populations Susceptibleinfectedresistant SIR model simplest model of disease incorporating immunity 0 No new births of susceptible individuals 0 Once resistance is gained it is retained S number of individuals susceptible to a pathogen l number of individuals infected R number of individuals developing resistance 0 g rate of transmission via contact between individuals 0 GRAB b rate of recovery and development of immunity 0 B for bcells of immune system 0 Probability of contact between susceptible and infected individuals Sl Rate of infection between susceptible and infected individuals Slg Rate of recovery of infected individuals lb Ration of new infections to recoveries reproductive ratio of parasite S I rate of infection 0 I b rate of recovery o R0gt1 l infection will spread o R0lt1 l infection fails to spread Parasite Adaptations 0 Evolution of adaptations to increase probability of transmission 0 Alter behavior of host Host Adaptations Immune system responses 0 Production of antibacterialantifungal compounds Mechanicalbiochemical defenses o Selfmedication CHAPTER 16 Competition Competition 0 lntraspeci c competition competition occurring between members of the same species 0 lnterspeci c competition competition occurring between individuals of different species 0 Can cause population of a species to decline or go extinct Resources things that organisms useconsume that cause and increase in population growth when they are abundant 0 Renewable constantly regenerated Can be generated from inside or outside the system Resources coming from outside the ecosystem do not respond to rate of consumption 0 Nonrenewable not regenerated xed availability Leibig s Law of the Minimum 0 Not all resources are limiting o Leibig39s Law of the Minimum most limiting resource prevents population from increasing further 0 Population will increase until the most limiting resource becomes scarce If 2 species compete for the same limiting resource the species that can drive abundance of the other species to the lowest level will survive Assumes that individual resources have independent effects on population growth Resource Interaction Increase of 2 resources can have a much bigger impact on a population than an increase of only 1 resource Competitive Exclusion Principle 0 2 species cannot coexist when both are limited by the same resource 0 One species is superior in obtaining resource or surviving when it is less available Competition Related Species Intense because species have similar traits and likely use similar resources 0 If competition is erce natural selection should favor differences in habitat use 0 Species have competitive advantage in their preferred habitat and disadvantages in nonpreferred habitats Competition Nonrelated Species Also intense if nonrelated species are consuming a common resource 0 Example space food water Modeling Competition for 1 Resource Competition coef cients convert relative population numbers between two different species 0 d competition coefficient for species 1 N1 0 V2 0 8 competition coefficient for species 2 N2 0 N1 leZr 1 Nl xNz 0 dt 1 1 K1 dN2r 1N2BN1 2 2 K2 0 Equilibrium 0 Species 1 N1K1 N2 OR when N1 isO 0 Species 2 N2K2BN1 ORwhen N2 isO 0 population growth isocline population size at which population experiences zero growth 0 Species 1 I When N220 N1K1 When N120 N2 0 SpeciesZ When N1O N2K2 When N220 N1 Predicting outcomes 0 Coexistence of 2 different species will happen when intraspeci c competition is more intense than interspeci c competition Competition for Multiple Resources o 2 species can coexist when each is better at persisting at low levels of different resources Other Factors 0 Abiotic conditions Disturbances Predation and herbivory tradeoff between ability to compete and resistance to predators Types of Competition Exploitative competition individuals consume and make a resource less abundant so that others cannot survive Interference competition competitors defend resources 0 Aggressive interactions 0 Allelopathy organisms use chemicals to harm competitors Apparent competition 2 species have negative effect on each other through an enemy 0 Competition combinations