Bio 1M03 - Exam Questions & Answers Solved 100%

Population - Answer - a group of individuals from the same species that occupy an area of space at the same time - can produce viable offspring - uses the same resources and are affected by similar factors Ecology - Answer - the study of how organisms interact with their environment What is population ecology? - Answer - measures changes in population size, pop composition - identifies factors that cause changes in population - studies how and why a population changes over tiime -IMP in terms of allocation of resources Survivorship - Answer - the proportion of offspring produced that survive on avg, to a specific age Survivorship Curve - Answer - a plot of the number of survivors vs age Cohort - Answer - a group of individuals of the same species that share a common characteristic which is being studied over a period of time Type 1 Survivorship Curve - Answer - survivorship throughout life is high, majority of individuals approach maximum life span - when the individuals get old, their survivorship decreases Type 2 Survivorship Curve - Answer - most individuals have a constant survivorship and mortaility over their lifetime Type 3 Survivorship Curve - Answer - high death rates are seen early in life, with high survivorship after maturity - after they reach a threshold age, they keep on surviving How can survivorship curves be used for conservation biology efforts? - Answer - Survivorship curves can help to conserve endangered species by putting in factors that will help a type 3 organism survive during its initial stages of life - For example, the green sea turtle population has been decreasing because some people eat their eggs. During the night when the eggs hatch, the turtles will try to run to the ocean but will get picked up by predators. Students can form canopies to protect the turtle and keep the predators away to increase survivorship. Life History [of an organism]/The principle of allocation - Answer - shows how an organism allocates out their resources towards reproduction, growth and other things associated with survival The Life Story of Daphnia - Answer - Daphnia are water fleas that are found in fresh water environments. - In the spring, a Daphnia does not have a spike on its head and it has a short spike on its tail because there is more resources and not as many predators, and it is allocating a lot of energy towards reproduction - In the summer, there will be more daphnia around and so it has to protect itself from predators. It will allocate its energy to form a spikier back and head as a trade-off towards reproduction Transgenic Mice: How does doubling growth impact on other features? - Answer - The mice will have rat growth hormone genes inserted into their genomes, causing them to grow bigger. Since growth is being exaggerated, it is using up more energy and resources from other internal functions, causing the other ones to get smaller. - The transgenic mice had INCREASED growth and sleep, but DECREASED longevity, reproduction, behaviour and feeding - It also had hair problems, skin problems, and didn't live as long What are the 2 characteristics of a population? - Answer - Density - Dispersion Density - Answer - number of individuals per unit area, or per unit volume at a given time Dispersion - Answer - the pattern of spacing in individuals within geographical boundaries Clumped Dispersion - Answer - group of individuals together in a specific area - i.e. sea stars are clumped together on rocks due to their suction cup structure Uniform Dispersion - Answer - group of individuals that are at an equal distance between each other - i.e. penguins, if one comes to close to another, the penguin will become irritated and let out a call Random Dispersion - Answer - group of individuals that are randomly dispersed - i.e. weeds and shrubs Density Measurement: Direct Count - Answer - you can count all of the individuals in a sample but this may take a lot of research and funding to monitor animal count - it may be impractical (i.e. counting seagulls) Density Measurement: Indirect Indicators - Answer you can estimate population density based on: - number of tracks - fecal droppings - burrows - nests Mark-Recapture Method - Answer - used to estimate population size N= (number of marked in 1st catch x total number in 2nd catch) / number of marked recaptures in 2nd catch Estimating Deer Population in Algonquin Park - Answer - You start by humanly collecting a number of deer and marking them with tags that are durable for all types of conditions, safe to the animal, and easily visible - In the first catch, 60 deer are tagged. In the 2nd catch, 60 deer are caught and 36 of those deer were recaptured deer from the first catch. N = (60x60)/36 = 100 deer What affects population growth? - Answer - rates of birth, death, immigration and emigration Density-Dependent Growth - Answer - biotic factors like predation, competition, diseases, and waste Density-Independent Growth - Answer - abiotic factors like weather, natural disasters and pollution Exponential Growth Equation - Answer - Change in population size N / Change in time t = r (the rate of increase) x N (number of individuals) - J shaped curve, ideal - the larger the r value, the larger the increase of the population over time - unlimited resources Logistic Population Growth Equation - Answer - population growth is rapid initially but then begins to slow as the population size reaches its carrying capacity (K), more realistic - dependent on population size Carrying Capacity (K) - Answer - the maximum stable population size that an environment can support with its available resources over a relatively long time period What trends would you expect in conditions of high population density? - Answer - Natural selection will favour adaptations that enhance survival (competitiveness) and reproduction with few resources (efficient use of resources) - lots of competition for resources - initial exponential growth - competition between or within a population What trends would you expect in conditions of low population density? - Answer - Natural selection will favour rapid rates of reproduction - If the population density is low, this must mean resources are little Demography - Answer - studies the factors that determine structure and size of a population - studies death rates, birth rates, immigration and emigraton Age Structure - Answer - the number of individuals of each age in a population - a population with older individuals grows slower than a population with younger individuals because young are reproductively capable - affects birth and death rate Age Pyramid - Answer - rapid growth - slow growth - zero growth Generation Time - Answer - the time span between the birth of individuals the birth of their offspring (i.e. the age pple start having kids at) - related to body size - a short generation time results in faster population growth if birth rate is greater than death rate Sex Ratio - Answer - number of individuals of each sex found in a population - number of females is directly related to number of births How has the human population growth changed over time? - Answer - the population has rapidly increased due to medical and industrial advances - this is a problem because we have a finite land mass -depends on the fertility rates Community - Answer - composed of different species living in the same area What are the 3 properties of a community? - Answer - Richness - Relative Abundance - Diversity Richness - Answer - the number of different species in a community - important to know in order to monitor diversity Relative Abundance - Answer - the number of individuals in each species within a community Diversity - Answer - the richness and relative abundance of species in a community Individualistic Hypothesis (Gleason) - Answer - focuses on a single species - a community has an UNSTABLE assemblage of species that occured by chance, living in the same area because they have similar abiotic requirements - the species are independently distributed and there are NO DISTINCT boundaries between communities Interactive Hypothesis (Clements) - Answer - a community has a STABLE assemblage of species living in the same area because they have predictable biotic interactions and they function as an integrated unit (i.e. they work together) - the species are clustered because there are DISTINCT boundaries between communities Rivet Model (Ehrlitch) - Answer - most species ARE closely associated with other species Redundancy Model (Gleason) - Answer - most species are NOT closely associated with other species Interspecific Interactions - Answer - occur between populations of different species living together within a community Competition - Answer - neither population benefits because it reduces population size of both species -/- - occurs when 2 or more species rely on a similar limiting resource Interference Competition - Answer - involves physical contact and fighting between species Exploitative Competition - Answer - involves the consumption of a limiting resource by one species making it unavailable for another species Predation/Consumption - Answer - there is a negative impact on the prey population size and a positive impact on the predator population size +/- Mutualism - Answer - a type of symbiosis where population sizes of both species are dependent on one another +/+ - Acacia trees provides homes for stinging ants live in and it also provides them with food. In return, the stinging ants protect the tree from any nearby herbivores that want to eat its leaves and it will cut off any overhanging branches so that the tree has exposure to the sun. Symbiosis - Answer - a relationship between 2 different species where the host species and symbiont species have close associations - an interaction between 2 different species living in close physical association with each other Commensalism - Answer - when one species benefits from another species and the other species remains neutral +/0 - Water Buffaloes walk in herds on grassland, and the insects in the grass do not want to be killed so they fly into the air. The Cattle Egret birds stays nearby to catch the flying insects. This benefits the bird but has no effect on the buffalo. Coevolution - Answer - involves a change in one species that acts as a selective force on another species - Passion Flower Vines produce toxic chemicals to reduce herbivory but Butterfly Larvae can tolerate the chemicals because they have digestive enzymes that can break down the chemicals Counteradapation - Answer - the counteradaption of the second species may affect the selection of individuals in the first species - The passion flower plant produces nectaries that look like butterfly larvae eggs so that the butterfly will not want to lay its eggs there due to competition and will try to find another plant. The nectaries will attract ants and wasps that will prey on the butterfly larvae eggs.