BIOL 201

• An endemic is a disease that occurs continually at a stable rate in a particular area.
• An epidemic is a disease that occurs locally at a higher than normal rate for a period of time.
• A pandemic is an epidemic that occurs on more than one continent at the same time
• A common-source epidemic usually shows a quick spike in cases and arises from contamination of water or food. Ex. cholera
• Host-to-host epidemics are diseases that show a slow, progressive rise and gradual decline. Ex. COVID-19
• What do the H and N stand for in H1N1 and so on?

  H stands for Hemaglutinin and N stands for neuraminidase; these are receptors that the virus binds to
• How do mutation and selection act in combination to drive the evolution of seasonal influenza?

  Antigenic drift - a type of gradual evolution where natural selection favors viruses that are immune to antibiotics
• Disease incidence depends on both the density of susceptible individuals, the density of infected individuals in the population, and the rate of encounter between infected and susceptible individuals
• Early in host-to-host epidemics, disease incidence grows exponentially
• R0 = SBL (susceptible x transmission rate x infectious period); the average number of individuals that a sick person infects in a population of entirely susceptible individuals
• If R0 > 1, what would this indicate?

  an epidemic would occur
• If R0 < 1, what would this indicate?

  no epidemic would occur
• Herd immunity occurs when the immunity of a high population protects susceptible individuals from exposure to disease; immunized people help because pathogens can't be passed so infectivity is broken.
• For rapidly spreading diseases (R0 >>>1): herd immunity can be achieved only if the vast majority of individuals have been infected (or immunized)
• For slowly spreading disease (R0 > 1): herd immunity can be achieved even if many individuals have not been infected (or immunized)
• Sexual dimorphism is the different physical characteristics due to differences in sex
• What is the primary limit on male fitness?

  it is limited by the ability to attract mates
• What is the primary limit on female fitness?

  by the ability to gain resources required to produce eggs and young
• When it comes to sexual asymmetry, males often undergo male-to-male competition. This can be seen through elaborate mating displays, direct combat, and sperm competition
• Most females prefer males who are more colored in their feathers and who provide them more resources for nests. What type of male-male competition is this?

  Elaborate Mating Displays
• The bigger the better as this provides more strength for combat. What type of male-male competition is this?

  Direct combat
• Males create optimal environments for females so they can deliver their sperm to them before males. What type of competition is this?

  Sperm competition
• For female preference, females exert a preference for males perceived to be of high quality
• Choosy females may benefit directly through the acquisition of resources. An example of this would be the bigger the male, the better the protection
• Choosy females may benefit indirectly by obtaining good genes that confer higher fitness in both sexes (good for survival). They could also have sexy sons which is the ability to attract more mates (good for fecundity)
• Runaway sexual selection is when a trait that is favored by one sex (usually females) is favored by both sexes and becomes more exaggerated over time.
• Sexual Selection causes two deviations from the Hardy-Weinberg (Null) model. It generates selection and causes mating to be non-random
• Altruism is the behavior that harms donor, but benefits the recipient
• According to Wynne-Edwards, Individuals might altruistically restrict their reproduction to avoid overpopulation and starvation. The altruistic behavior would then be favored as the groups containing such individuals would survive. What would this result in?

  An increased cooperation would increase mutual benefits and strengthen social bonds, but it would increase the risk of inbreeding which could reduce the overall fitness of the population
• What is a good example of selection favoring an altruistic trait that benefits the group at a cost of the individual?

  Vampire bats. They would limit sharing with strangers but share it with relatives and/or friends harming the donor but extending the life of another
• If birds from Nestbox 3 joined to mob an owl placed in Nestbox 1, how should the birds from Nestbox 1 behave if an owl dummy is placed in Nestbox 3?

  Attack it, this is a form of reciprocal altruism
• Individuals should be more willing to perform altruistic acts for kin than non-kin. Why?

  Inclusive Fitness. This would increase the benefit future generations; Br - C > 0
• When calculating the coefficient of relatedness, half of the alleles are passed on by each generation. Remember to add the alleles from both parents.
• Genetic drift is the random change in allele frequencies in a population due to chance and can lead to more loss of genetic diversity. More pronounced in smaller populations.
• The bottleneck effect is when the frequency of an allele stays the same at first but then gravitates to either 1 or 0 over time as a result of genetic drift in a small population (illustrates genetic drift)
• As a result of the bottleneck effect, the average of a certain allele frequency stays the same but the variance of a certain allele frequency changes over time
• Heterozygosity = f(heterozygotes)/total individuals
• Ht = (1 - 1/2N)^t(H0); heterozygosity after t generations
• A limited # of territories means a limited # of males that successfully mate. Genetic variation is lost even faster when the sex ratio of breeding individuals is not 50:50
• If there is an unequal sex ratio, the alleles most males are expressing will have a higher frequency as generations pass.