Humans and most primates
have a Type I survivorship curve. In a Type I curve, organisms tend not to die when they are young or middle-aged but, instead, die when they become elderly.
What is an example of a type 1 survivorship curve?
Organisms that exhibit Type I survivorship curves have the highest probability of surviving every age interval until old age, then the risk of dying increases dramatically.
Humans
are an example of a species with a Type I survivorship curve. Others include the giant tortoise and most large mammals such as elephants.
Do elephants have a Type 1 survivorship curve?
Elephants have a Type I survivorship curve (mortality increases with age), and fecundity decreases with age.
Are frogs Type 1 survivorship curve?
Other organisms that display a type I survivorship curve include elephants, gorillas and annual grasses. … Most frog species display a
type III survivorship curve
, where the death rate is very high early in life and much lower in the middle and older age groups.
Are bears Type 1 survivorship curve?
This urban bear population
no
longer exhibits the Type I survivorship curve generally associated with large mammals that produce few offspring.
What is a Type 3 survivorship curve?
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
.
How do you calculate a survivorship curve?
A survivorship curve is a graph that measures the proportion of individuals in a given species that are alive at different ages. Typically, the number of individuals of the population is plotted on the y-axis of the graph and the
age of survivorship is plotted on the x-axis of the graph
.
What is a Type 2 survivorship curve?
Populations with Type II survivorship
have a constant proportion of individuals dying over time
. … For example, the type II curve has a constant proportion of individuals dying each time period. Starting with 1,000 individuals, in the first time period if 40% survive, then only 400 will be left.
What is a characteristic of Type 1 survivorship curves?
Type I or convex curves are characterized by
high age-specific survival probability in early and middle life, followed by a rapid decline in survival in later life
. They are typical of species that produce few offspring but care for them well, including humans and many other large mammals.
What does it mean to say that most large mammals have Type 1 survivorship curves?
Survivorship curves show the distribution of individuals in a population according to age. Humans and most mammals have a Type I survivorship curve,
because death primarily occurs in the older years
. Birds have a Type II survivorship curve, as death at any age is equally probable.
What is a late loss survivorship curve?
Type 1
is the late loss survivorship curve. This means that mortality is very low in the infant, juvenile, and adult years. Type 2 is the constant loss survivorship curve. This means that mortality is very high during early life stages, followed by a very low death rate for the individuals reaching adulthood.
What causes a Type 2 survivorship curve?
In a Type II curve,
organisms die more or less equally at each age interval
. Organisms with this type of survivorship curve may also have relatively few offspring and provide significant parental care.
How is survivorship calculated?
To calculate l
1
, survivorship from age 0 to age 5,
subtract the proportion of the population dying during that interval from 1.0
(i.e., l
1
= l
0
– proportion dying during interval 0). To calculate survivorship for age group 2, subtract the proportion dying during period 2 (6-10 years) from l
1
.
What survivorship curve are black bears?
Population Density
Black bears fall under
type 1 of
the survivorship curve. They belong in this group because they produce very few offspring, but provide for them well, resulting in a high survival rate of young.
Why do K selected species have a Type 1 survivorship curve?
Because time, energy and resources are invested into child rearing
, K -selected species tend to have a Type 1 and Type 2 survivorship curve. Offspring live longer lives and grow slowly until their habitat hits the carrying capacity.
Under what circumstances might human populations not show type 1 survivorship?
Under what circumstances might human populations not show type I survivorship.
Third world populations typically have high infant mortality
and due to other environmental stresses show population decline at all life stages.
