Themes in the Study of Life

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Slide 31

Systems Biology

A system is a combination of components that function together

Systems biology constructs models for the dynamic behavior of whole biological systems

The systems approach poses questions such as:

How does a drug for blood pressure affect other organs?

How does increasing CO2 alter the biosphere?

Slide 32

Theme: Organisms interact with their environments, exchanging matter and energy

Every organism interacts with its environment, including nonliving factors and other organisms

Both organisms and their environments are affected by the interactions between them

For example, a tree takes up water and minerals from the soil and carbon dioxide from the air; the tree releases oxygen to the air and roots help form soil

Slide 33

Ecosystem Dynamics

The dynamics of an ecosystem include two major processes:

Cycling of nutrients, in which materials acquired by plants eventually return to the soil

The flow of energy from sunlight to producers to consumers

Slide 34

Fig. 1-5

Sunlight

Ecosystem

Heat

Heat

Cycling

of

chemical

nutrients

Producers

(plants and other photosynthetic

organisms)

Chemical energy

Consumers

(such as animals)

Slide 35

Energy Conversion

Work requires a source of energy

Energy can be stored in different forms, for example, light, chemical, kinetic, or thermal

The energy exchange between an organism and its environment often involves energy transformations

Energy flows through an ecosystem, usually entering as light and exiting as heat

Slide 36

Theme: Structure and function are correlated at all levels of biological organization

Structure and function of living organisms are closely related

For example, a leaf is thin and flat, maximizing the capture of light by chloroplasts

Slide 37

(a) Wings

(c) Neurons

(b) Bones

Infoldings of

membrane

Mitochondrion

(d) Mitochondria

0.5 µm

100 µm

Fig. 1-6

Slide 38

Fig. 1-6a

(a) Wings

Slide 39

Fig. 1-6b

(b) Bones

Slide 40