What are the two types of population curves?
Two modes of population growth. The Exponential curve (also known as a J-curve) occurs when there is no limit to population size. The Logistic curve (also known as an S-curve) shows the effect of a limiting factor (in this case the carrying capacity of the environment).
What does Type 2 survivorship curve mean?
A type II survivorship curve shows a roughly constant mortality rate for the species through its entire life. This means that the individual’s chance of dying is independent of their age. Type II survivorship curves are plotted as a diagonal line going downward on a graph.
What animal has a Type 2 survivorship curve?
For populations with Type II survivorship, the mortality of an individual does not depend on its age. Commonly listed examples of this include rodents, adult birds, and certain turtle species.
What is population curve?
The growth of the population eventually slows nearly to zero as the population reaches the carrying capacity (K) for the environment. The result is an S-shaped curve of population growth known as the logistic curve. It is determined by the equation. carrying capacity and exponential versus logistic population growth.
What is S shaped curve?
S-shaped growth curve(sigmoid growth curve) A pattern of growth in which, in a new environment, the population density of an organism increases slowly initially, in a positive acceleration phase; then increases rapidly, approaching an exponential growth rate as in the J-shaped curve; but then declines in a negative …
What are Type 2 species?
life tables In contrast, the Type II curve considers birds, mice, and other organisms characterized by a relatively constant mortality or survivorship rate throughout their life expectancies.
What is Type 3 survivorship curve?
life tables In survivorship curve. The Type III curve, characteristic of small mammals, fishes, and invertebrates, is the opposite: it describes organisms with a high death rate (or low survivorship rate) immediately following birth.
What is a Type 3 curve?
Type III or concave curves have the greatest mortality (lowest age-specific survival) early in life, with relatively low rates of death (high probability of survival) for those surviving this bottleneck. This type of curve is characteristic of species that produce a large number of offspring (see r/K selection theory).
Why do birds have a Type 2 survivorship curve?
Birds are an example of an intermediate or Type II survivorship curve because birds die more or less equally at each age interval. These organisms also may have relatively few offspring and provide significant parental care.