Chapter 1 Introduction : Biology Today

I. Characteristics of Life

• Cells

• Metabolism / Energy Utilization

• Homeostasis

• Growth and Development

• Reproduction

• Evolution

1. Cells.

2. Metabolism / Energy Utilization.

3. Homeostasis.

4. Growth and Development.

5. Reproduction.

6. Evolution.

II. LEVELS OF ORGANIZATION

BIOSPHERE – ECOSYSTEM – COMMUNITY – POPULATION – ORGANISM – ORGAN SYSTEM – ORGAN – TISSUE – CELL – MOLECULE – ATOM

A. BIOSPHERE – ECOSYSTEM – COMMUNITY – POPULATION – ORGANISM – ORGAN SYSTEM – ORGAN – TISSUE – CELL – MOLECULE - ATOM

Fig 1.3

B. The dynamics of any ecosystem depend on two processes

• Cycling of nutrients

• Flow of energy

C. Cells overview

1.

2.

3. Two Basic Types (Fig 1.5)

• Prokaryotic

• Eukaryotic

Prokaryotic

no nucleus

smaller

simpler

Eukaryotic

prominent nucleus

larger

more complex

III. Diversity of life – Overview

Problem: How do we classify forms of life?

Solution: Group according to similarities

cell organization

energy source

A. Smallest group – species

· can interbreed successfully

B. Largest group – domain (Fig 1.8)

· Domain Bacteria - prokaryotic

· Domain Archaea - prokaryotic

· Domain Eukarya – eukaryotic

Kingdom Protista – mostly unicellular

Kingdom Fungi – decomposers

Kingdom Plantae – make own food

Kingdom Animalia – ingest food

The three domains of life are:

1.

2.

3.

KNOW - Which domains are Prokaryotic and which are Eukaryotic?

IV. Evolution – Biology’s unifying theme – not “just a theory”

Evolution - process that has transformed life on Earth from its earliest beginnings to the extensive diversity of today.

(Fig 1.11)

• Life evolves

• Each species is one twig of a branching tree of life extending back in time

A. Idea of fixed species

1. Proposed by Aristotle (Greek philosopher)

2. Maintained by Judeo-Christian culture

This theory of fixed species states that:

•

•

B. Idea that species change through time

1. Anaximander (pre-dated Aristotle).

Proposed that

-

-

2. 1700’s

a. Buffon’s fossil study suggested:

-

-

b. Lamarck suggested organisms interact within the environment and adapt

3. 1800’s

a. Lyell presented geological argument for an ancient earth

b. Darwin and Wallace made separate world voyages and careful, extensive observations

Observation #1

Individuals in a population vary

1. Population with varied inherited traits.

2. Elimination of individuals with certain traits.

3. Reproduction of survivors.

4. Increasing frequency of traits that enhance survival and reproductive success.

Fig 1.14

Observation #2

Overpopulation leads to a struggle for existence

Conclusion

Individuals with traits best suited to local environment will have the greatest reproductive success

Darwin called this