1. Introduction: Biology Today Figures 1.3 – 1.9
CHAPTER 1
Introduction: Biology Today
Figures 1.3 – 1.9

2. Each organism interacts continuously with its environment
Ecosystems
Each organism interacts continuously with its environment
Both organisms and environment are affected by the interactions
Ecology is the branch of biology that investigates these relationships between organisms and their environment

3. The dynamics of any ecosystem depend on two processes
Sunlight
Ecosystem
Heat
Cycling of nutrients
Flow of energy
Consumers
(such as animals)
Heat
Producers
(plants and other
photosynthetic
organisms)
Chemical
energy (food)
Figure 1.3

4. Cells and Their DNA
The cell is the lowest level of structure that can perform all activities required for life
All organisms are composed of cells

5. We can distinguish two major types of cells
Prokaryotic
Eukaryotic

6. The prokaryotic cell is simple and contains no organelles
Nucleus
(contains
DNA)
The eukaryotic cell is more complex and contains organelles
The nucleus is the largest organelle in most eukaryotic cells
Eukaryotic cell
Prokaryotic cell
DNA
(no nucleus)
Organelles
Figure 1.4

7. All cells use DNA as the chemical material of genes
Genes are the units of inheritance that transmit information from parents to offspring
The language of DNA contains just four letters
A, G, C, T
Figure 1.5

8. Genetic engineering and biotechnology have allowed us to manipulate the DNA and genes of organisms
Figure 1.6

9. Life in Its Diverse Forms
Diversity is the hallmark of life
The diversity of known life includes 1.7 million species
Estimates of the total diversity range from 5 million to over 30 million species

10. Grouping Species: The Basic Concept
Biodiversity can be both beautiful and overwhelming
Taxonomy is the branch of biology that names and classifies species
It formalizes the hierarchical ordering of organisms
Figure 1.7

11. The Three Domains of Life
The three domains of life are
Domain Bacteria
Domain Archaea
Bacteria
Archaea
Eukarya
Domain Eukarya
Kingdom Protista
Kingdom Plantae
Kingdom Fungi
Kingdom Animalia
Figure 1.8.1

12. Bacteria and Archaea are both prokaryotic domains
Domain Bacteria
Domain Archaea
Figure 1.8.2

13. Eukarya includes at least four kingdoms
Domain Eukarya
Protista
Plantae
Fungi
Animalia
Kingdom Protista
Kingdom Plantae
Kingdom Fungi
Kingdom Animalia
Figure 1.8.3

14. Unity in the Diversity of Life
Underlying the diversity of life is a striking unity, especially at the lower levels of structure
Example: the universal genetic language of DNA
Evolution accounts for this combination of unity and diversity

15. The universal architecture of eukaryotic cilia
(a) Paramecium
(b) Cells from
fallopian
tube
(c) Cross section of cilium
Figure 1.9