<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Question.</strong> List the attributes that populations possess but not individuals.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Ans.</strong> Some significant attributes that populations but not individual possess are:</p> <p>(i) Natality</p> <p>(ii) Death rate</p> <p>(iii) Birth rate</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p>(iv) Population density</p> <p>(v) Population dispersion</p> <p>(vi) Population age distribution</p> <p>(vii) Sex ratio</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Question.</strong> If a population growing exponentially double in size in 3 years, what is the intrinsic rate of increase (r) of the population?</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Ans.</strong> The exponential growth equation:</p> <p>Nt = $N_0$ $^{ert}$</p> <p>Where</p> <p>Nt = population after time t</p> <p>N0 = initial population</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p>t = time</p> <p>r = intrinsic rate of increase of population</p> <p>Giv</p> <p>en $N_0$ = x</p> <p>Nt = 2x</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p>t = 3</p> <p>2x = x $e^{3r}$</p> <p>$e^{3r}$ = 2</p> <p>r = 0.2311</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Question.</strong> Name important defence mechanisms in plants against herbivory.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Ans.</strong> There are various defence measures for animals against predators. But plants, as they cannot move away, have certain defence mechanisms against herbivory. Their main defences are chemical toxins, such as strychnine, a poison produced by tropical vine, morphine by opium poppy, nicotine produced by tobacco plant. Apart from these chemicals,</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p>the common defence measure is presence of spines (modified leaves) on the leaves, stems of the plant, modifications of leaves into thorns, development of sharp silicated edges in leaves which prevent them against damage caused by herbivores.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Question.</strong> An orchid plant is growing on the branch of mango tree. How do you describe this interaction between the orchid and the mango tree?</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Ans.</strong> An orchid plant is growing on the branch of a mango tree is called epiphyte, i.e., plants growing on other plants or trees. This type of interaction is known as commensalism, where in orchid/derives benefit of interaction whereas mango tree is not affected. The orchid growing on the branch of mango tree get more light to grow and also, the mango is not harmed in any way.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Question.</strong> What is the ecological principle behind the biological control method of managing with pest insects?</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Ans.</strong> The ecological principle behind the biological control method of managing with pest insects in predator prey relationship where by the predator feeds on the prey.</p> <p>Hence, the predators regulate the population of preys in a habitate, thereby helping management of pest insect.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Question.</strong> Define population and community.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Ans.</strong> <strong>Population:</strong> Population can be defined as the total number of individuals of a species or any other class of an organism in a defined area or habitat or a group of individuals of the same species within a community.</p> <p><strong>Community:</strong> Community can be defined as a naturally occurring assemblage of species living within a defined area or habitat.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Question.</strong> Define the following terms and give one example for each:</p> <p>(a) Commensalism</p> <p>(b) Parasitism</p> <p>(c) Camouflage</p> <p>(d) Mutualism</p> <p>(e) Interspecific competition</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Ans.</strong></p> <p>(a) Commensalism is the association between organisms of different species in which one species benefits while other remains unaffected. For example, in the large intestine of human being, bacteria Escherichia coli are present which helps in digestion.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p>(b) Parasitism is an association in which one organism where one organism is benefitted at the expense of other. For example, the parasites of humans include fleas and lice, various bacteria, protozoans and fungi.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p>(c) Camouflage is a high degree of similarity between an animal and its visual environment, which enables it be disguised or concealed. For example, birds with necks and heads of contrasting colours are not easily recognised by their enemies under certain conditions.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p>(d) Mutualism is an association between two organisms of different species in which both get benefited. For example, the cross fertilization or pollination of plant flowers by insects (sometimes by birds) is a mutual relation of wide occurrence and great importance, because many plants are self- sterile.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p>(e) Inter-specific competition can be defined as competition between organism of two different species for a common resource. For example, when two species of Paramecium, Paramecium caudatum and P.aurelia are confined in a closed containers with fixed amount of food, out of them one species always died out.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Question.</strong> With the help of suitable diagram describe the logistic population growth curve.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Ans.</strong> The S-shaped growth curve is also called a logistic growth curve. It describes a situation in which (in a new environmental condition) the population density of an organism increases slowly establishing itself then increasing rapidly, approaching an exponential growth rate. Many population of micro-organisms broadly follow this basic sigmoidal pattern.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p>For example, when a fresh culture medium is inoculated with bacteria, sigmoidal or S-shaped growth curve is observed. The S-shaped curve is generated when a population approaches the environmental’s carrying capacity. Carrying capacity is the maximum number of individuals of a population that can be supported in a given time.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Question.</strong> Select the statement which explains best parasitism.</p> <p>(a) One organism is benefited.</p> <p>(b) Both the organisms are benefited.</p> <p>(c) One organism is benefited, other is not affected.</p> <p>(d) One organism is benefited, other is affected.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Ans.</strong> (d) One organism is benefited, other is affected.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Question.</strong> List any three important characteristics of a population and explain.</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>Ans.</strong> The three important characteristics of a population are:</p> <p><strong>(a) Population Density:</strong> The number of individuals per unit area is called population density. For example, the number of frogs per m2 of forest region.</p> <p>$\text{Population density} = \frac{\text{Number of people}}{\text{Area of land}}$</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>(b) Natality or Birth rate:</strong> The birth rate is determined by the number of individuals born to a given population during a given period of time.</p> <p>$\text{Natality or Birthrate} = \frac{\text{Number of birth}}{\text{Total number of individual in a population}}$ $\times{100}$</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>

<p><Success style = "float: center; text-align: center; font-size:30px"><B>Organisms and Populations</B></Success></p> <p><Primary style = "float: center; text-align: center; font-size:26px"><B>Excercises</B></Primary></p> <hr> <main> <div style='float: left; width:100%; text-align: left;font-size:23px'> <p><strong>(c) Mortality or Death rate:</strong> The death rate or mortality represents a decrease in a given population during a given period of time. Generally, the death of individuals in a population are expressed by specific mortality which is described as the mortality population are expressed by specific mortality which is described as the mortality for given age group.</p> <p>$\text{Mortality or Death rate} = \frac{\text{Number of death}}{\text{Total number of individual in a population}}$ $\times{100}$</p> </div> </main> <hr> <footer style= "font-size:18px"><span style="color:blue">Excercises</span></footer>