Transcript 02_Hierarchy of Life PPS

Hierarchy of Life
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Chapter 1
An Introduction to Biology
Key Concepts:
1.1 Principles of Biology and the Levels of
Biological Organization
1.2 Unity and Diversity of Life
2
1.1 Principles of Biology
Biology: the scientific study of living things.
1. Cells are the simplest units of life
2. Living organisms use energy
3. Living organisms interact with their
environment
3
Principles of Biology
4. Living organisms maintain homeostasis
5. Living organisms grow and develop
6. The genetic material provides a blueprint
for reproduction
4
Principles of Biology
7. Populations of organisms evolve from
one generation to the next
8. All species (past and present) are related
by an evolutionary history
9. Structure determines function
5
Principles of Biology
10. New properties of life emerge from
complex interactions
11. Biology is an experimental science
12. Biology affects our society
6
Levels of Biological Organization
Molecules and
1
Atoms
2 macromolecules
3
5
6
4
Organs
Cells
Tissues
Organism
10 Biosphere
7
Population
9
8
Ecosystem
Community
7
1.2 Unity and Diversity of Life

Unity
 All
life displays a common set of characteristics
 United

by a shared evolutionary history
Diversity

Life has a diversity of form in diverse environments
8
Evolutionary History

Life began on Earth as primitive cells between
3.5 - 4 billion years ago (bya)

Those primitive cells underwent evolutionary
changes to give rise to the species of today

Evolutionary history helps us understand
the structure and function of an organism
9

Evolutionary change involves modifications
of pre-existing characteristics

Structures may be modified to serve new
purposes

Example:
Walking limbs
were modified into
a dolphin’s flipper
or a bat’s wing
10
Two Mechanisms of Evolutionary
Change
1.
Vertical descent with modification

Progression of changes in a lineage

New species evolve from pre-existing species by
the accumulation of mutations

Natural selection takes advantage of beneficial
mutations
11
Vertical Evolution: The Horse Lineage
0
Hippidium and
other genera
Equus
5
Nannippus
Styohipparion
Hipparion Neohipparion
Pliohippus
10
Sinohippus
Megahippus
Calippus
Millions of years ago (mya)
Archaeohippus
20
Anchitherium
Merychippus
Hypohippus
Parahippus
Miohippus
Mesohippus
40
Paleotherium
Epihippus
Propalaeotherium
Pachynolophus
55
Hyracotherium
Orohippus
12
2.
Horizontal gene transfer

Genetic exchange between different species

Relatively rare

Genes that confer antibiotic resistance are
sometimes transferred between different bacteria
species
13
Horizontal Gene Transfer: Antibiotic Resistance
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
DNA
DNA
Antibioticresistance
gene
Antibioticresistance
gene from
E. coli
Horizontal
gene
transfer to
another
species
Bacterial species such as
Escherichia coli
Bacterial species such as
Streptococcus pneumoniae
14
Tree or web of life?

Horizontal gene transfer was an important part
of the process that gave rise to modern species

Tree of life focuses on vertical evolution
 The
tree of life is predictive
 Placement of a new species on the tree of life
immediately informs us about its biology
 Understanding relationships among species allows
biologists to make predictions about species that have
not yet been studied

Web of life includes the contribution of horizontal
gene transfer
15
Web of Life: Vertical Evolution and Horizontal Gene Transfer
Bacteria
Archaea
Eukarya
Fungi
Animals
Plants
Protists
KEY
Vertical evolution
Horizontal gene transfer
Common ancestral community of primitive cells
16
Classification

Taxonomy is the grouping of species based on
common ancestry

Three domains of life
 Bacteria
- unicellular prokaryote
 Archaea
- unicellular prokaryote
 Eukarya
- unicellular and multicellular eukaryotes

Complex cells with a nucleus and organelles

Four kingdoms:
 Protista,
Plantae, Fungi, and Animalia
17
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Domain Bacteria:
Mostly unicellular prokaryotes
that
inhabit many diverse
environments on Earth
Domain Archaea:
Unicellular prokaryotes
that often live
in extreme environments,
such as hot springs
© Dr. David M. Phillips/Visuals Unlimited
18
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Protists
Plants
Fungi
Animals
1: © Dr. Dennis Kunkel/ Visuals Unlimited; 2: © Kent Foster/Photo Researchers; 3: © Carl Schmidt-uchs/Photo Researchers; 4: © Fritz Polking/Visuals Unlimited
Domain Eukarya: Unicellular and multicellular organisms
having cells with internal compartments that serve various functions
Classification

A species is placed into progressively
smaller groups that are more closely related

Emphasizes the unity and diversity of different
species

Example:
 Clownfish
20
Taxonomic
group
Clown
anemonefish
is found in
Approximate time
when the common
ancestor for this
group arose
Approximate
number of
modern species
in this group
Domain
Eukarya
2,000 mya
> 5,000,000
Kingdom
Animalia
600 mya
> 1,000,000
Phylum
Chordata
525 mya
50,000
Class
Actinopterygii
420 mya
30,000
Order
Perciformes
80 mya
7,000
Family
Pomacentridae
~ 40 mya
360
Genus
Amphiprion
~ 9 mya
28
Species
ocellaris
> 3 mya
1
Examples
21

Binomial nomenclature
 Each
species has a unique scientific name
 Genus
name capitalized
 Species
 Both
descriptor is not capitalized
names are italicized
Amphiprion ocellaris = Clownfish
22
Genomes and Proteomes

Genome - the complete genetic makeup of an
organism

Genomics - techniques used to analyze DNA sequences
 Comparison

Proteome - the complete complement of proteins of
an organism

Proteomics - Comparison of proteomes of different species
 Techniques

of genomes of different species
used to analyze the proteins of a species
The study of genomes and proteomes provides an
evolutionary foundation for our understanding of
biology

Fundamental to understanding an organisms characteristics
23
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
In eukaryotes, most of the genome
is contained within chromosomes
that are located in the cell nucleus
Gene
(a) The genome
Most genes encode mRNAs
that contain the information
to make proteins
Cytoplasm
Chromosome
Chromosome
DNA
Cell signaling:
Proteins are needed
for cell signaling with
other cells and with
the environment
Sets
Sets of
of
chromosomes
chromosomes
Nucleus
Nucleus
Cytoskeleton:
Proteins are involved
in cell shape and
movement
Cell organization:
Proteins organize the
components within
cells
Enzymes:
Proteins function as
enzymes to synthesize
and break down
cellular molecules and
macromolecules
Transport proteins:
Proteins facilitate the
uptake and export of
substances
Extracellular fluid
(b) The proteome
Extracellular
proteins:
Proteins hold cells
together in tissues
24