Deck 1: Life: Biological Principles and the Science of Zoology

Question 1

Why is life difficult to define?

Answer 1

It is difficult to define life as there are no defining properties for life. The properties exhibited in the beginning are different from the properties we see today. This is because evolution has taken place.
In the same way, unexpected properties have emerged and are seen in different combinations today. So it is difficult to set down standard properties for "life".
Hence scientists have taken a few characteristics seen in almost all organisms and given them as the properties of "life".

Question 2

What are the basic chemical differences that distinguish living from nonliving systems?

Answer 2

The basic chemical differences that differentiate between living and non living systems are:
• Living systems are made up of chemical molecules like carbohydrates, proteins, nucleic acids and lipids.
• A hierarchical system of organization of matter exists in living systems
• A genetic program is present in the nucleic acids of living systems
• Living systems take required nutrients from their surroundings for their growth and development. These nutrients are used in the process of metabolism.

Question 3

Describe the hierarchical organization of life. How does this organization lead to the emergence of new properties at different levels of biological complexity?

Answer 3

Living things are highly organized in a "hierarchical" manner: lower levels of organization are progressively integrated to make up higher levels. The building blocks of matter, called atoms, lie at the base of life's organizational structure.
This hierarchical organization leads to the emergence of new properties at different levels of biological complexity. The emergence of new properties at a particular level is influenced and restricted by the properties of the components of the lower levels. An animal which cannot hear cannot develop speech and language. It is also dependent on the interaction of the different components to give rise to novel combinations.

Question 4

What is the relationship between heredity and variation in reproducing biological systems?

Question 5

Describe how evolution of complex organisms is compatible with the second law of thermodynamics.

Question 6

What are the essential characteristics of science? Describe how evolutionary studies fit these characteristics whereas "scientific creationism" or "intelligent-design theory" does not.

Question 7

Use studies of natural selection in British moth populations to illustrate the hypothetico-deductive method of science.

Question 8

How do we distinguish the terms hypothesis, theory, paradigm, and scientific fact?

Question 9

How do biologists distinguish experimental and evolutionary sciences?

Question 10

What are Darwin's five theories of evolution (as identified by Ernst Mayr)? Which are accepted as fact and which continue to stir controversy among biologists?

Question 11

What major obstacle confronted Darwin's theory of natural selection when it was first proposed? How was this obstacle overcome?

Question 12

How does neo-Darwinism differ from Darwinism?

Question 13

Describe the respective contributions of the genetic approach and cell biology to formulating the chromosomal theory of inheritance.