Sections 1.3

1
Chapter 1

• Sections 1.3
• Studying Life

2
What is Biology?

• Biology is the science that seeks to understand
  the living world
• A biologist is someone who uses scientific
  methods to study living things

3
Living things

• Are made up of units called cells
• Reproduce
• Are based on a universal genetic code
• Grow and Develop
• Obtain and use energy and materials
• Respond to their environment
• Maintain a stable internal environment
• Change over time

4
Made up of Cells

• A cell is a collection of living matter enclosed
  by a barrier that separates the cell from its
  surroundings

5
Characteristics of a Cell

• They can grow
• They respond to their environment
• They reproduce

6
Reproduction

• Sexual Reproduction- two cells from different
  parents unite to produce the first cell of the
  new organism
• Ben Affleck Jennifer Garner Hollywood Baby

7
Reproduction

• Asexual reproduction- the new organism has a
  single parent
• Example single celled organism divides to form
  two new organisms (figure 1-16)

8
Based on a Genetic Code

• Living organisms inherit traits from their
  parents
• Inherited traits are determined by the organisms
  DNA (deoxyribonucleic acid)

9
Growth and Development

• Different organisms grow and develop differently
  at different stages in life
• Consider fetus, child, adolescent, adult

10
Need for Materials and Energy

• Why do you need to eat?
• Metabolism- the combination of chemical through
  which an organism builds up or breaks down
  materials as it carries out its life processes
• Think why do pregnant women and teenagers need
  to eat more food?

11
Response to the Environment

• Organisms detect and respond to stimuli from
  their environment
• Stimulus- a signal to which an organism responds
• Examples seeds germinating, leaves changing
  color, migration

12
Maintaining Internal Balance

• Homeostasis- process by which organisms keep
  their internal environment constant
• Temperature, water content, etc.

13
How do they do that?

• Homeostasis is usually maintained by internal
  feedback mechanisms
• Thermostat
• Example hunger, thirst, sweat, shivering

14
Evolution

• As a group, organisms can evolve, or change over
  time
• Over time, organisms change to adapt to their
  environment
• Figure 1-20 on page 20 of text

15
Branches of Biology

• Biosphere
• Ecosystem
• Community
• Population
• Organism
• Groups of Cells
• Cells
• Molecules