Chapter 15.2, Problem 1NV

Use your book or dictionary to define the following terms.

Derived trait_________________________________________

Ancestral trait________________________________________

Homologous structures__________________________________

Vestigial structure______________________________________

Analogous structures___________________________________

____________________________________________________

Embryo ______________________________________________

Biogeography _________________________________________

fitness_______________________________________________

_____________________________________________________

camouflage____________________________________________

mimicry_______________________________________________

Summary Introduction

To determine:

Definition of the terms derived traits, ancestral traits, homologous structures, vestigial structures, analogous structures, embryo, biogeography, fitness, camouflage and mimicry.

Explanation of Solution

Derived traits are those characteristics or traits, which are acquired by the organism itself and it was not present in any of its ancestor. These also include the structure, which was present in ancestors but not in the organism, this represents the loss of the trait. They may or may not be genetically determined.

Ancestral traits are the characteristics, which are passed to the organism from its ancestors. These traits are genetically determined.

Homologous structures are the structures, which share the structural similarity between two organisms, but the functions of these structures can be different. These are ancestral structures, which adapted to perform different functions.

Vestigial structures are the structures present in the body of an organism that might have a function in past or ancestors, but during evolution, they become non-functional and are still present in the body of an organism.

Analogous structures are the structures or characteristics, which have similar functions in different species, but the structures are not similar. They are said to be convergent in nature, as two different organisms evolved the same characteristics for living in similar conditions.

In a sexually reproducing organism, the embryo is a developmental stage of a multicellular organism. It is the developmental stage that starts with fertilization and continues until the differentiation of the cells in different tissues and organs.

Biogeography is described as the study of the distribution of different organisms in different regions. It deals with the fact that different geographical regions have different types of organisms adapted to that particular environment.

Fitness in biology is defined as the ability to survive in a particular environment. This describes the adaptation and the characteristics of the species, which help them utilize maximum resources to survive and reproduce in a better way.

Camouflage is a technique adopted by many organisms to get blended with the habitat. This is an evolutionary defense strategy, in which the outer color of the organism is similar to the place they are living in so that predators or prey cannot easily spot them.

Some of the species evolve to look like each other to escape predation and this behavior is known as mimicry. It can be of two types, Batesian and Mullerian, in Batesian mimicry, a non-harmful species evolves to look like a harmful one and in Mullerian mimicry, two noxious species evolve to look like each other.