Transcript Life, 6th Edition

Chapter 1: An Evolutionary Framework for Biology
CHAPTER 1
An Evolutionary Framework
for Biology
Chapter 1: An Evolutionary Framework for Biology
An Evolutionary Framework
for Biology
Introduction
Organisms Have Changed over Billions of Years
Evolutionary Milestones
The Hierarchy of Life
Chapter 1: An Evolutionary Framework for Biology
Chapter 1: An Evolutionary
Framework for Biology
Asking and Answering “How?” and “Why?”
Biology and Public Policy
Chapter 1: An Evolutionary Framework for Biology
Introduction
• If Earth’s history were a 30-day month,
recorded human history would occupy the
last 30 seconds.
Chapter 1: An Evolutionary Framework for Biology
1.1
Time...
Chapter 1: An Evolutionary Framework for Biology
Organisms Have Changed
over Billions of Years
• Evolution unites all of biology. The idea and
evidence of evolution existed before Darwin.
Chapter 1: An Evolutionary Framework for Biology
Organisms Have Changed
over Billions of Years
• The theory of evolution by natural selection
rests on two observations and one inference
from them.
Chapter 1: An Evolutionary Framework for Biology
Evolutionary Milestones
• Life arose from non-life about 3.8 billion
years ago.
• All living organisms contain the large
molecules—carbohydrates, lipids, proteins,
and nucleic acids.
• All organisms consist of cells, and all cells
come from preexisting cells.
• A major theme in evolution is increasingly
diverse ways of capturing external energy
for biologically useful reactions.
Chapter 1: An Evolutionary Framework for Biology
Evolutionary Milestones
• The evolution of sexual reproduction
enhanced the ability of organisms to adapt
to changing environments.
• Photosynthetic single-celled organisms
released oxygen, allowing oxygen-based
metabolism of large cells and eventually
multicellular organisms.
• Complex eukaryotic cells evolved from
prokaryotic cells. Eukaryotic cells developed
into multicellular organisms whose cells
became modified for specific functions.
Chapter 1: An Evolutionary Framework for Biology
Evolutionary Milestones
• Regulated growth is a vital characteristic of
life.
• Speciation resulted in the millions of species
living on Earth today.
• Organisms developed complicated systems
to respond to internal and external
environmental change and for homeostasis.
• Adaptation to environmental change is the
result of evolution by natural selection.
Chapter 1: An Evolutionary Framework for Biology
The Hierarchy of Life
• Biology is organized into a hierarchy of
levels. Each has emergent properties not
found at lower levels.
Chapter 1: An Evolutionary Framework for Biology
1.9
Hierarchy of
Life
Chapter 1: An Evolutionary Framework for Biology
The Hierarchy of Life
• Species are classified into domains Archaea,
Bacteria, and Eukarya. Archaea and Bacteria
consist of prokaryotic cells. Eukarya contain
the protists and the kingdoms Plantae,
Fungi, and Animalia.
Chapter 1: An Evolutionary Framework for Biology
1.10
Taxonomy
Chapter 1: An Evolutionary Framework for Biology
Asking and Answering
“How?” and “Why?”
• Biologists ask how organisms work, and why
they evolved to work that way.
• How and why questions are usually
answered using a hypothetico-deductive (HD) approach.
• Science is based on the formulation of
testable, rejectable hypotheses. Acceptance
of refuted, untested, or untestable
assumptions is not science.
Chapter 1: An Evolutionary Framework for Biology
Biology and Public Policy
• Biologists often advise governmental
agencies regarding problems with a
biological component.
• Biology is a critical component to health and
welfare, and the viability of societies - both
regional and global.