BuyFindarrow_forward

Biology: The Dynamic Science (Mind...

4th Edition
Peter J. Russell + 2 others
ISBN: 9781305389892

Solutions

Chapter
Section
BuyFindarrow_forward

Biology: The Dynamic Science (Mind...

4th Edition
Peter J. Russell + 2 others
ISBN: 9781305389892
Textbook Problem

Gregory M. Erickson of Florida State University and colleagues from Florida State and the University of Alberta analyzed a fossil assemblage of 22 individuals of Albertosaurus sarcophagus, a relative of Tyrannosaurus rex. All 22 had died at roughly the same time—but at different ages—perhaps because of a drought or starvation. They used growth lines present in the fossilized leg bones to determine the age at death of each specimen. They had no data for very young individuals, and assumed a 60% mortality rate between birth and age two. The researchers constructed the following Table extrapolated to an initial cohort of 1,000 individuals:

Age (years) Number Surviving
0 1000
1 __
2 400
3 __
4 382
5 __
6 364
7 __
8 345
9 327
10 __
11 309
12 291
13 273
14 255
15 218
16 182
17 164
18 127
19 109
20 73
21 56
22 __
23 36
24 __
25 __
26 __
27 __
28 18

Did this population of animals exhibit a Type I, Type II, or Type III survivorship pattern—or something intermediate? What does the life table tell you about the age at which A. sarcophagus was most vulnerable to the factors causing mortality?

Source: After G. M. Erickson et al. 2006. Tyrannosaur life tables: An example of nonavian dinosaur population biology. Science 313:213–217.

Summary Introduction

To review:

The determination of the survivorship pattern of Albertosaurus sarcophagus and determine the factors making these animals vulnerable to mortality.

Analysis of fossil assemblage of 22 individuals of Albertosaurus sarcophagus, a relative of Tyrannosaurus rex. All 22 died at the same time probably, but at different ages due to starvation. Growth lines present in fossilized leg bones were used to determine the age of death of each specimen. No data for very young individuals were obtained and 60% mortaility rates between birth and age too were assumed. Further, the table is extrapolated to 1000 individuals as given :

Biology: The Dynamic Science (MindTap Course List), Chapter 52, Problem 1ITD

Introduction:

There are different types of species that have different anatomy, behavioral patterns, and habitat. Species also differ in their life span. We can track down the life of these different organisms with the help of survivorship table and curve. This table provides a reference to the birth of organisms born at the same time die in each year or unit time.

Explanation

There are basically three types of survivorship curves :

Type 1 (convex curves): It has high chances of survival in early and middle life while more deaths occur during later stage of life. These types of organisms of species produce few offsprings who remain under well care. Examples, humans, large mammals.

Type 2 (diagonal curves): It has almost constant mortality rate throughout their life span regardless of their age. This curve is mainly shown by birds and lizards.

Type 3 (concave curves): It shows the lowest survival rate. The mortality rate is rapid in early life and the mortality rate decreases further. They have the lowest rates of survival and these types of species produce a number of offsprings...

Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started

Additional Science Solutions

Find more solutions based on key concepts

Show solutions add

How can errors in the cell cycle lead to cancer in humans?

Human Heredity: Principles and Issues (MindTap Course List)

A pregnant woman needs an extra 450 calories above the allowance for nonpregnant women during which trimester(s...

Nutrition: Concepts and Controversies - Standalone book (MindTap Course List)

What is the difference between a law and a theory?

An Introduction to Physical Science

If you were 10 design an electric healer using Nichrome wire as the healing element, what parameters of the wir...

Physics for Scientists and Engineers, Technology Update (No access codes included)