Test 2 Study Guide PDF

Define life history. An organism’s life history is a record of events relating to its growth, development, reproduction, and survival Identify the characteristics that define life history. - Age and size at sexual maturity - Amount and timing of reproduction - Survival and mortalit...

Define life history. An organism’s life history is a record of events relating to its growth, development, reproduction, and survival Identify the characteristics that define life history. - Age and size at sexual maturity - Amount and timing of reproduction - Survival and mortality rates Describe a life history strategy. The life history strategy of a species is the overall pattern in the average timing and nature of life history events. Define phenotypic plasticity and provide an example. What is a morph? Provide an example. - Morph: a continuous range of growth rates or discrete types produced by phenotypic plasticity - Ex. Spadefoot toad tadpoles in Arizona ponds contain both omnivore morphs and larger carnivore morphs Describe a complex life cycle. Complex life cycles involve at least two distinct stages that may have different body forms and live in different habitats Define metamorphosis. Metamorphosis: abrupt transition in form from the larval to the juvenile stage Define direct development. What is more common in nature, a complex life cycle or direct development? A complex life cycle Provide an example of each. Complex: Frogs and other amphibians: Undergo metamorphosis, transitioning from a tadpole larva to an adult frog with distinct body forms. Direct: humans / cats / dogs young hatch or are born looking similar to the adult form, just smaller Describe alternation of generations. a multicellular diploid sporophyte alternates with a multicellular haploid gametophyte Explain the difference between the sporophyte and gametophyte. sporophyte: the diploid phase that produces spores through meiosis gametophyte: the haploid phase that produces gametes (sex cells) through mitosis Define r-selection and provide an example. r is the intrinsic rate of increase of a population Rabbits / fish / insects / frogs Define K-selection and provide an example. K is the carrying capacity for a population; selection for slower growth rates in populations that are at or near K Humans / elephants / whales / large mammals Be able to identify the traits of r- and K-selected species. r: small size, fast development, short lived, many offspring, no parental care K: large size, slow development, long live, reproduction later in life Define a trade-off. organisms allocate limited energy or resources to one structure or function at the expense of another Explain why a common trade-off in nature is between the size and number of offspring. the larger an organism’s investment in each individual offspring, the fewer offspring it can produce What are the advantages of sexual reproduction? - Increased genetic diversity - Ability to adapt to a changing environment What are the disadvantages of sexual reproduction? - Only pass 50% of your genetic material on to offspring - Energy expenditure - Production of males - STDs Describe the red queen effect. (Makes Sex Beneficial) - Organisms must constantly adapt and evolve not only to reproduce but to survive against other organisms (parasites/pathogens) that are constantly evolving in a changing environment - Explains the importance of sexual reproduction in generating genetic diversity Define sexual dimorphism and explain what traits are commonly observed. a difference between two sexes in secondary sexual characteristics (males and females feature different appearances)  - size - color - body shape - ornamentation Define intrasexual selection. What types of traits are favored? Selection in which there is direct competition between individuals of the same sex Traits that make a male more successful in reproduction will be favored - Help a male attract females (ornaments) - Help males win contests / fights (armaments) Be able to explain how intrasexual selection can lead to: - Extreme variance in reproductive success - Territoriality - Alternative mating strategies Define intersexual selection. individuals of one sex are choosy in selecting their mates from the other sex Be able to explain the following hypotheses for female mate choice: - Direct benefits: benefits the female directly - Indirect benefits: benefits that affect the genetic quality of the females offspring - Sexual conflict: fitness traits that benefit one sex but cost the other Describe the different types of mating systems: - Promiscuous: no strong pair-bonds or lasting relationships - Monogamous: one male mates with one female - Polygamous: an individual of one sex mates with multiple individuals of the other sex Describe sperm competition. - Observed in species where females mate with multiple males and may contain sperm from multiple males at the same time - Can be costly to a male – he doesn’t want to invest in another male’s offspring What is anisogamy? - Females are “choosy” and males are “cheap” Describe how anisogamy explains the difference in female and male reproductive strategies. - Females invest lots of energy to produce few eggs must be choosy for best male possible (Limited by fecundity) - Males produce large amounts of sperm goal is to maximize matings (Limited by the number of mates they can obtain) How are paternity, parental care, and reproduction related? - Paternal certainty is relatively low in species with internal fertilization because mating and birth are separated over time - Certainty of paternity is much higher when egg laying and mating occur together, as in external fertilization Define the operational sex ratio. ratio of males to females capable of reproducing at a given time Define distribution. geographic area over which individuals of a species occur Define abundance. the number of individuals in a specific area Define population. group of individuals of the same species that live within a particular area and interact with one another Identify and describe the two ways that abundance of a population is reported. Abundance can be reported as population size (# individuals) or density (# individuals per unit area) Be able to calculate population density. Describe the abiotic factors that affect population distribution. moisture, temperature, pH, sunlight, nutrients Describe the biotic factors that affect population distribution. herbivores, predators, competitors, parasites and pathogens Describe an ecological disturbance and provide an example. - events that kill or damage some individuals, creating opportunities for other individuals to grow and reproduce - Fires, floods, storms, insect/pest outbreaks, landslides, invasive species Define geographic range. the entire geographic region over which a species is found Explain why a species may have a patchy distribution. Many species have patchy distributions because not all habitat within the range is suitable Define dispersion. is the spatial arrangement of individuals within a population Describe the types of dispersion: - Regular (uniform) individuals are evenly spaced - Random individuals scattered randomly - Clumped individuals are grouped together Be able to describe the following methods used to estimate absolute population size: - Area-based counts - Mark-recapture methods - Niche modeling Be able to calculate absolute population size, using the mark-recapture method. N=DxA Explain the difference between absolute and relative population size. "Absolute population size" refers to the actual, raw number of individuals in a population, while "relative population size" represents the proportion of a population compared to another population or a reference point Describe an ecological niche. the physical and biological conditions that a species needs to grow, survive, and reproduce Name the four processes that can change population size. - birth - death  - immigration - emigration Explain why carrying capacity in nature is rarely constant. Birth and death rates vary over time Describe a population cycle and provide an example. - Some populations have alternating periods of high and low abundance at regular intervals - Example: Populations of small rodents such as lemmings and voles typically reach a peak every 3–5 years Define environmental stochasticity. changes in the average birth or death rates that occur from year to year because of random changes in environmental conditions Define demographic stochasticity. population-level birth and death rates are constant within a given year, but the actual fates of individuals differ based on chance events Describe a metapopulation. partially isolated populations that are linked by the dispersal of individuals or gametes What two factors characterize metapopulations? repeated extinctions and colonizations What factors can make some populations prone to extinction? - The landscapes they live in are patchy (making dispersal between populations difficult)  - Environmental conditions often change in a rapid and unpredictable manner (i.e. environmental stochasticity) Define habitat fragmentation. large tracts of habitat are converted to spatially isolated habitat fragments by human activities, resulting in a metapopulation structure Explain how habitat fragmentation affects isolation, colonization, and extinction. Patches may become ever smaller/more isolated, reducing colonization and increasing extinction Describe a life table. a summary of how survival and reproductive rates vary with age Define the following: - Survival rate chance that an individual of age x will survive to age x + 1 - Survivorship proportion of individuals that survive from birth to age x - Fecundity average number of offspring a female will have at age x Explain the difference between a cohort and static life table. - Cohort life table: follows the fate of a group of individuals all born at the same time (a cohort) - Static life table: survival and reproduction of individuals of different ages during a single time period Describe the different types of survivorship curves and provide an example of each: - Type I most individuals survive to old age - Type II the chance of surviving remains constant throughout the lifetime  - Type III high death rates for young; those that reach adulthood survive well Explain how survivorship curves relate to r- and K-selection. it shows that species categorized as "K-selected" typically have a Type I survivorship curve (high survival throughout life), while "r-selected" species tend to have a Type III curve, characterized by high mortality in early life stages and much lower mortality for those who survive to adulthood Describe exponential growth. when individuals reproduce continuously and generations can overlap and the population changes in size by a constant proportion at each instant in time Is exponential growth associated with r- or K-selection? Provide an example. - r - selection - A population of mice rapidly increasing in number in a new environment with abundant resources would be considered an example of r-selection and exponential growth Describe logistic growth. population increases rapidly, then stabilizes at the carrying capacity Define carrying capacity. maximum population size that can be supported indefinitely by the environment Is logistic growth associated with r- or K-selection? Provide an example. - K - selection  - Elephants are considered a K-selected species, as they have a long lifespan, produce few offspring, and exhibit logistic growth due to their stable population size regulated by the environment's carrying capacity Describe density-independent factors and list examples. - Effects on birth and death rates are independent of the number of individuals in the population. - Weather conditions (i.e. temperature, precipitation) or catastrophes (i.e. floods or hurricanes) Describe density-dependent factors and list examples. - birth, death, and dispersal rates change as the density of the population changes - Competition for Resources, Toxic Wastes, Predation Explain why no population can grow forever. every environment has a limited carrying capacity Describe what is meant by the term exploitation. a relationship in which one organism benefits by feeding on, and thus directly harming, another Define the following feeding strategies: - Herbivore eats the tissue or internal fluids of living plants or algae - Predator kills and eats other organisms, referred to as prey - Parasite lives in or on another organism (host), feeding on parts of the it (don’t always kill the host) (Some parasites (pathogens) cause disease) Describe the following types of prey adaptations:  - Camouflage prevents capture - Startle prevents capture - Warn prevents capture - Disrupt escape capture Describe plant adaptations to herbivory. Tobacco plants have two induced defenses: - Toxic secondary compounds that deter herbivores directly - Compounds that deter herbivores indirectly by attracting predators and parasitoids Some tropical plants in the genus Bursera produce toxic sticky resins and store them in canals in leaves and stems - If an insect herbivore chews through one of the canals, the resin squirts from the plant under high pressure to repel or even kill the insect Describe anti-predator behavior. - mechanisms developed through evolution that assist prey organisms in their constant struggle against predators. Explain compensation in response to herbivory in plants. a plant's ability to regrow or produce new biomass after being partially eaten by herbivores Describe and provide examples of predator adaptations. Predator adaptations include physical features like sharp teeth and claws, enhanced senses for detecting prey, camouflage to blend in with the environment, high speed for pursuit, specialized hunting strategies, and in some cases, venom or toxins to subdue prey; examples include a lion's powerful jaws and claws, a snake's infrared vision to locate warm-blooded prey, a chameleon's color-changing ability for camouflage, a cheetah's incredible speed, and a spider's web to trap insects. Explain the effects that predation and herbivory can have on a community and provide an example. regulating the population sizes of prey and plant species, influencing their distribution, and even shaping the overall structure of the ecosystem; for example, the removal of a top predator can lead to an explosion in herbivore populations, which can then drastically reduce plant biomass, impacting the entire community through a phenomenon called a "trophic cascade." Define symbiont. are organisms that live in or on other organisms As humans, do we have symbiotic relationships? Explain. Yes, humans are hosts to many microscopic mites that live on the skin Define parasite. is an organism that has an intimate relationship with its host at some point in the parasite’s life cycle and MAY harm the host Define pathogen. parasites that cause diseases Define parasitoid. an organism whose larvae feed on a single host, almost always kill it Describe host specificity. Most parasites feed on only one or a few individual host organisms Define hyperparasitism. Most species infected by more than one kind of parasite (even parasites have parasites) Describe ectoparasitism and provide an example. live on the outer body surface of the host Describe endoparasitism and provide an example. live within the host, in the alimentary canal, or within cells or tissues Explain the advantages and disadvantages of ectoparasitism and endoparasitism. Describe the defenses against parasites that are utilized by plants and animals. - Protective outer coverings include skin and exoskeletons - Vertebrate immune systems have specialized “memory cells” that allow hosts to recognize microparasites it has been exposed to in the past - Other immune system cells engulf and destroy parasites or mark them with chemicals that target them for later destruction macrophage Explain counterdefenses by parasites, using Plasmodium as an example. Plasmodium faces two challenges in the human host - Red blood cells do not divide or grow, and thus cannot import nutrients so Plasmodium merozoites must have a way to get nutrients 24–48 hours after infection - Plasmodium causes red blood cells to have an abnormal shape that is detected by the spleen, where they are destroyed Define coevolution. when populations of two interacting species evolve together, each in response to selection imposed by the other Explain the Red Queen hypothesis as it relates to parasitism. Provide an example. Ever-escalating “arms races” (i.e. the Red-Queen hypothesis) rarely occur As with the snails and trematodes, common host genotypes decrease in frequency because they are attacked by many, leading to increase in previously rare genotypes. Describe the ecological effects of parasites. By reducing host performance and growth rates of host populations, parasites can change the outcome of species interactions, community composition, and even the physical environment