(24) When would a population have a clumped distribution and when would a population have a uniform distribution (what are the advantages and disadvantages to each distribution type)?
A. Clump distribution is when individuals occur in groups. For example, suitable habitat or other resources may be distributed as patches resulting in clump distributions. Uniform distribution is when individuals are spread apart equally. For example, when competition for resources is intense it tends to be uniform distribution.
Advantages of clump distribution are – protection from predator, raising offspring, and increasing chance of catching prey. Disadvantages are – resources are limited, competition among each other
Advantages of uniform – more resources for the individual Disadvantages -
B.A population has a clumped population when there are social interactions between the individuals. Another reason would be there are small colonies. Also when there is no distribution of seeds, like when the annual seeds just drop.
A population has a uniform population when resources are scarce and the other individuals will press the other individual out.
C.http://en.wikipedia.org/wiki/Species_distribution
Clumped distribution
Clumped distribution is the most common type of dispersion found in nature. In clumped distribution,the distance between neighboring individuals is minimized. This type of distribution is found in environments that is characterized by patchy resources. Clumped distribution is the most common type of dispersion found in nature because animals need certain resources to survive, and when these resources become rare during certain parts of the year animals tend to “clump” together around these crucial resources. Individuals might be clustered together in an area due to social factors such as selfish herds and family groups, for example wolves in packs. Organisms that usually serve as prey form clumped distributions in areas where they can hide and detect predators easily.
Other causes of clumped distributions are the inability of offspring to independently move from their habitat. This is seen in juvenile animals that are immobile and strongly dependent upon parental care. For example, the bald eagle's nest of eaglets exhibits a clumped species distribution because all the offspring are in a small subset of a survey area before they learn to fly. Clumped distribution can be beneficial to the individuals in that group. However, in some herbivore cases, such as cows and willdabeasts, the vegetation around them can suffer, especially if animals target one plane in particular.
Clumped distribution in species acts as a mechanism against predation as well as an efficient mechanism to trap or corner prey. African wild dogs, Lycaon pictus, use the technique of communal hunting to increase their success rate at catching prey. It has been shown that larger packs of African wild dogs tend to have a greater number of successful kills. A prime example of clumped distribution due to patchy resources is the wildlife in Africa during the dry season; lions, hyenas, giraffes, elephants, gazelles, and many more animals are clumped by small water sources that are present in the severe dry season.[1] It has also been observed that extinct and threatened species are more likely to be clumped in their distribution on a phylogeny. The reasoning behind this is that they share traits that increase vulnerability to extinction because related taxa are often located within the same broad geographical or habitat types where human-induced threats are concentrated. Using recently developed complete phylogenies for mammalian carnivores and primates it has been shown that the majority of instances threatened species are far from randomly distributed among taxa and phylogenetic clades and display clumped distribution.[2]
Monday, March 22, 2010
(23) What are the characteristics of a population? What factors limit the distribution of a population?
A. The characteristics of a population are the number of births, the number of deaths, the number of reproductively mature individuals, the survival rate, and the immigration/ emigration.
Limiting factors are food, water, space, precipitation, temperature, diseases, sex ratio, quality of habitat, oxygen, natural disasters, competition (interspecific and intraspecific).
B.http://www.mansfield.ohio-state.edu/~sabedon/campbl52.htm
Population
(a) A population in an ecological sense is a group of organisms, of the same species, which roughly occupy the same geographical area at the same time
(b) Individual members of the same population can either interact directly, or may interact with the dispersing progeny of other members of the same population (e.g., pollen)
(c) Population members interact with a similar environment and experience similar environmental limitations
A. The characteristics of a population are the number of births, the number of deaths, the number of reproductively mature individuals, the survival rate, and the immigration/ emigration.
Limiting factors are food, water, space, precipitation, temperature, diseases, sex ratio, quality of habitat, oxygen, natural disasters, competition (interspecific and intraspecific).
B.http://www.mansfield.ohio-state.edu/~sabedon/campbl52.htm
Population
(a) A population in an ecological sense is a group of organisms, of the same species, which roughly occupy the same geographical area at the same time
(b) Individual members of the same population can either interact directly, or may interact with the dispersing progeny of other members of the same population (e.g., pollen)
(c) Population members interact with a similar environment and experience similar environmental limitations
(21) Discuss the difference between a R selected species and a K selected species. Give an example of an organism in each group.
A. (See table 12.1 in lecture notes)
An example of a R selected species is salmon. An example of a K selected species is human.
B.R-strategists are short lived, have high reproductive rates, rapid development, small in size, large number of offspring, and minimal parental care. Some r-strategists have wide dispersal, are good colonizers, and respond rapidly to disturbance. K-strategists are competitive species with stable populations of long lived individuals. They have slower growth rate at low populations, but they maintain growth rate at high densities. K-strategists can cope with physical and biotic pressures. They have late reproduction and have large body size and slow development. They also have few offspring and usually care for the offspring. They are efficient users of a particular environment, but their populations are at near carrying capacity and resources are limited. They lack the means for wide dispersal making them poor colonizers.
An example of a K-selected specie is whales. Whales are long lived and have small populations. Whales have very few offspring and take care of their offspring. They grow and mature over a long period of time. They reproduce at a later age when mature. An example of an R-selected are rats because they often have large litters and are always fertile. They don’t live long, grow fast, have large populations, and have rapid growth.
C. R selected species tend to have short life spans and large clutches. Examples of these include mice and frogs. K selected species tend to have long lives and long juvenile periods as well as only one child at a time an example is tortoises.
D.http://en.wikipedia.org/wiki/R/K_selection_theory
r-selection (unstable environments)
In unstable or unpredictable environments, r-selection predominates as the ability to reproduce quickly is crucial. There is little advantage in adaptations that permit successful competition with other organisms, because the environment is likely to change again. Traits that are thought to be characteristic of r-selection include: high fecundity, small body size, early maturity onset, short generation time, and the ability to disperse offspring widely. Organisms whose life history is subject to r-selection are often referred to as r-strategists or r-selected. Organisms with r-selected traits range from bacteria and diatoms, through insects and weeds, to various semelparous cephalopods and mammals, especially small rodents.
[edit] K-selection (stable environments)
In stable or predictable environments, K-selection predominates as the ability to compete successfully for limited resources is crucial and populations of K-selected organisms typically are very constant and close to the maximum that the environment can bear (unlike r-selected populations, where population sizes can change much more rapidly). Traits that are thought to be characteristic of K-selection include: large body size, long life expectancy, and the production of fewer offspring that require extensive parental care until they mature. Organisms whose life history is subject to K-selection are often referred to as K-strategists or K-selected. Organisms with K-selected traits include large organisms such as elephants, trees, humans and whales, but also smaller, long-lived organisms such as Arctic Terns.
A. (See table 12.1 in lecture notes)
An example of a R selected species is salmon. An example of a K selected species is human.
B.R-strategists are short lived, have high reproductive rates, rapid development, small in size, large number of offspring, and minimal parental care. Some r-strategists have wide dispersal, are good colonizers, and respond rapidly to disturbance. K-strategists are competitive species with stable populations of long lived individuals. They have slower growth rate at low populations, but they maintain growth rate at high densities. K-strategists can cope with physical and biotic pressures. They have late reproduction and have large body size and slow development. They also have few offspring and usually care for the offspring. They are efficient users of a particular environment, but their populations are at near carrying capacity and resources are limited. They lack the means for wide dispersal making them poor colonizers.
An example of a K-selected specie is whales. Whales are long lived and have small populations. Whales have very few offspring and take care of their offspring. They grow and mature over a long period of time. They reproduce at a later age when mature. An example of an R-selected are rats because they often have large litters and are always fertile. They don’t live long, grow fast, have large populations, and have rapid growth.
C. R selected species tend to have short life spans and large clutches. Examples of these include mice and frogs. K selected species tend to have long lives and long juvenile periods as well as only one child at a time an example is tortoises.
D.http://en.wikipedia.org/wiki/R/K_selection_theory
r-selection (unstable environments)
In unstable or unpredictable environments, r-selection predominates as the ability to reproduce quickly is crucial. There is little advantage in adaptations that permit successful competition with other organisms, because the environment is likely to change again. Traits that are thought to be characteristic of r-selection include: high fecundity, small body size, early maturity onset, short generation time, and the ability to disperse offspring widely. Organisms whose life history is subject to r-selection are often referred to as r-strategists or r-selected. Organisms with r-selected traits range from bacteria and diatoms, through insects and weeds, to various semelparous cephalopods and mammals, especially small rodents.
[edit] K-selection (stable environments)
In stable or predictable environments, K-selection predominates as the ability to compete successfully for limited resources is crucial and populations of K-selected organisms typically are very constant and close to the maximum that the environment can bear (unlike r-selected populations, where population sizes can change much more rapidly). Traits that are thought to be characteristic of K-selection include: large body size, long life expectancy, and the production of fewer offspring that require extensive parental care until they mature. Organisms whose life history is subject to K-selection are often referred to as K-strategists or K-selected. Organisms with K-selected traits include large organisms such as elephants, trees, humans and whales, but also smaller, long-lived organisms such as Arctic Terns.
(20) For a given allocation to reproduction, there is a trade-off between the number and the size of offspring produced. What types of environment would favor plant species with a strategy of producing many small seeds rather than few large ones?
A.Plants in competitive environment would produce many small seeds because it would increase the chances that there would be offspring that survive. Producing large seeds would decrease the chance of having an offspring survive in because there might be too much competition for resources for the large seed to develop and grow.
B.The larger the offspring produced the more energy and resources went into making the offspring and the single offspring has a higher chance of survival and less competition. Having many offspring means that your genes aren’t supported by only one child. Some offspring will and can die but your genetic coding will continue on. Environments rich in nutrients warm temperature and fresh water would favor large clutches.
A.Plants in competitive environment would produce many small seeds because it would increase the chances that there would be offspring that survive. Producing large seeds would decrease the chance of having an offspring survive in because there might be too much competition for resources for the large seed to develop and grow.
B.The larger the offspring produced the more energy and resources went into making the offspring and the single offspring has a higher chance of survival and less competition. Having many offspring means that your genes aren’t supported by only one child. Some offspring will and can die but your genetic coding will continue on. Environments rich in nutrients warm temperature and fresh water would favor large clutches.
(19) What factors can influence the reproductive success of an organism? When would it be beneficial to allocate more resources to growth rather than reproduction?
A. All limiting factors mentioning in question 23
It would be more beneficial to allocate more resources to growth rather than reproduction when species have to live in a competitive habitat. Their priorities are food, spaces, water and other resources. That’s why they need to grow as much as possible to be able to stand the harshness of their living environment.
B.Factors that affect reproductive success of an organism – environment, survival, resources, genes, and adaptation.
C.Factors that can influence the success of an organism reproduction include amount of water, food/ nutrients available, surviving infancy. If there are more resources available then a large family makes since prepare for the future. Sometimes it makes more since to concentrate on growth if you don’t believe offspring wont survive because there are few resources.
D.>> predations, environment... when the environmental condition is harsh it is more
E.The ability of one the male to capture the interest of the female. Limited energy allocated to reproduction. The more energy they spend on reproduction, the less for growth and maintenance.
A. All limiting factors mentioning in question 23
It would be more beneficial to allocate more resources to growth rather than reproduction when species have to live in a competitive habitat. Their priorities are food, spaces, water and other resources. That’s why they need to grow as much as possible to be able to stand the harshness of their living environment.
B.Factors that affect reproductive success of an organism – environment, survival, resources, genes, and adaptation.
C.Factors that can influence the success of an organism reproduction include amount of water, food/ nutrients available, surviving infancy. If there are more resources available then a large family makes since prepare for the future. Sometimes it makes more since to concentrate on growth if you don’t believe offspring wont survive because there are few resources.
D.>> predations, environment... when the environmental condition is harsh it is more
E.The ability of one the male to capture the interest of the female. Limited energy allocated to reproduction. The more energy they spend on reproduction, the less for growth and maintenance.
(18) If you discover a new species, what information would you need to know to determine how that species diverged from another species?
A.Species that diverged from each other long ago have more differences in their DNA than species that diverged recently. Scientists use this degree of difference as a molecular clock to help them predict how long ago species split apart from one another. In general the longer ago two species split, the more distantly related they are. Because the DNA sequence determines a protein's amino acid sequence, a gene shared by two closely related organisms should have similar, or even identical, amino acid sequences. That's because closely related species most likely diverged from one another fairly recently in the evolutionary span. Thus, they haven't had as much time to accumulate random mutations in their genetic codes.
B.>> look at phylogeny differences/similarities, etc.
A.Species that diverged from each other long ago have more differences in their DNA than species that diverged recently. Scientists use this degree of difference as a molecular clock to help them predict how long ago species split apart from one another. In general the longer ago two species split, the more distantly related they are. Because the DNA sequence determines a protein's amino acid sequence, a gene shared by two closely related organisms should have similar, or even identical, amino acid sequences. That's because closely related species most likely diverged from one another fairly recently in the evolutionary span. Thus, they haven't had as much time to accumulate random mutations in their genetic codes.
B.>> look at phylogeny differences/similarities, etc.
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