Science

# What is a Type 2 survivorship curve?

By: Mat ColUpdated: February 02, 2021

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A survivorship curve is a graph showing the number or proportion of individuals surviving to each age for a given species or group (e.g. males or females). Type II or diagonal curves are an intermediate between Types I and III, where roughly constant mortality rate/survival probability is experienced regardless of age.

Keeping this in view, what is a Type 2 species?

Type II. Many bird species have a Type II 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.

Likewise, what organisms have a Type 2 survivorship curve?

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. Certain lizards, perching birds, and rodents exhibit this type of survivorship curve.

What animal has a Type 1 survivorship curve?

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 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.

## Related

### What is the difference between a Type I and Type III survivorship curve?

There are three types of survivorship curves. Type I curves depict individuals that have a high probability of surviving to adulthood. Type II curves depict individuals whose chance of survival is independent of age. Type III curves depict individuals that mostly die in the early stages of their life.

### How is survivorship calculated?

Survivorship is calculated as the relative change in the number of individuals of the cohort between two successive censuses. The census is very simple, since individuals need only be recognized to differentiate them from other cohorts in the same population, and thus are only counted.

### What survivorship curve is humans?

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.

### How is survivorship LX calculated?

First, the proportion surviving to each life stage (lx) can be found by dividing the number of indivuals living at the beginning of each age (ax) by the initial number of eggs (a0). Conversely, the proportion of the original cohort dying dur- ing each age (dx) is found by subtracting lx+1 from lx.

### What factors affect survivorship curves?

Besides the constraint of the general life history strategy of a species, the shape of survivorship curves can be affected by both biotic and abiotic factors, such as competition and temperature.

### What type of survivorship curve do fish have?

Trees, marine invertebrates, and most fish have a Type III survivorship curve. In a Type III curve, very few organisms survive their younger years.

### Why can't a female lizard have both high fecundity and high survival?

Why can't a female lizard have both high fecundity and high survival? The more energy the female devotes to offspring, the less that can be devoted to her survival. What is the primary limiting factor that determines why no female animal can produce a very large number of very large eggs?

### Which characteristics would lead to a population being most likely to have a type III survivorship curve?

Type III curves occur in populations with high mortality in early age classes and very low mortality in older individuals. Populations displaying a Type III survivorship curve generally need to have high birth rates in order for the population size to remain constant.

### What animals are r strategists?

Typical examples of r-species are mice, rabbits, weeds and bacteria, which have a lot of offspring, but a short life expectancy. Examples of organisms undergoing K-selection are tortoises, elephants, people, and sequoia trees: their offspring are few but long-lived.

### What can one infer from a relatively linear survivorship curve?

Answer and Explanation: Survivorship curves show the relationship between age and the proportion of the population that survive. So, an organism that exhibit a linear survivorship curve would have the mortality rate be roughly uniform across its lifespan, so answer A would be the best answer.

### Why do birds have a Type 2 survivorship curve?

Many bird species have a Type II 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.

### Do you think there is any relationship between survivorship curves and reproductive strategies?

Reproductive and Survivorship Strategies. In addition to various reproductive strategies, organisms differ in their survivorship strategies. Some organisms are at high risk of dying early in life, but if they can survive long enough, they have a decreasing probability of dying as the years go on.

### What type of survivorship curve do elephants have?

Elephants have a Type I survivorship curve (mortality increases with age), and fecundity decreases with age.