Evolution and Biodiversity
Chapter 4
Core Case Study: Life on Earth
Uniquely suited for life
•
Temperature range
•
Liquid water
•
Gravitational mass
•
Oxygen
Organisms contribute to relatively consistent
planetary conditions
–
resilient and adaptive
Biodiversity and sustainability
The Right Mix of Conditions
Fig. 4
-
1, p. 63
4
-
1 What Is Biological Evolution and How
Does It Occur?
Concept 4
-
1A
The scientific theory of evolution
explains how life on earth changes over time
through changes in the genes of populations.
Concept 4
-
1B
Populations evolve when genes
mutate and give some individuals genetic traits
that enhance their abilities to survive and to
produce offspring with these traits (natural
selection).
Theory of Evolution
4.7 billion years
Explains why life so diverse
Supported by
fossils
, chemical analysis of
primitive rock, DNA, and ice cores
Fossilized Skeleton of a Cenozoic
Herbivore
Fig. 4
-
2, p. 65
Population Changes over Time
Populations evolve by becoming genetically
different
Genetic variability
–
mutation
Natural Selection
Genetically favorable traits to survive and
reproduce
Trait
–
heritable and lead to
differential
reproduction
Faced with environmental change
•
Adapt
•
Migrate
•
Become extinct
Coevolution
Changes in gene pool of one species lead to
changes in gene pool of the other
Bats and moths
Science Focus: How Did We Become
Such a Powerful Species?
Key adaptations
–
also enabled us to modify
environment
Evolved very recently
Technology dominates earth’s life support
systems and NPP
4
-
2 How Do Geological and Climate
Changes Affect Evolution?
Concept 4
-
2
Tectonic plate movements,
volcanic eruptions, earthquakes, and climate
change have shifted wildlife habitats, wiped out
large numbers of species, and created
opportunities for the evolution of new species.
Plate Tectonics
Locations of continents and oceans determine
earth’s climate
Movement of continents allow species to move
and adapt
Earthquakes and volcanoes affect biological
evolution
Movement of Continents
Fig. 4
-
3, p. 67
Present
65 million years ago
135 million years ago
225 million years ago
Present
225 million years ago
65 million years ago
135 million years ago
Fig. 4
-
3, p. 67
Stepped Art
Earth’s Long
-
term Climate Changes
Cooling and warming periods
–
affect evolution
and extinction of species
Five mass extinctions
•
Eliminated half of the earth’s species
•
Many theories why this occurred
Opportunities for the evolution of new species
Northern Hemisphere over 18,000 Years
Fig. 4
-
4, p. 67
18,000
years before
present
Modern day
(August)
Northern Hemisphere
Ice coverage
4
-
3 What Is an Ecological Niche?
Concept 4
-
3
As a result of biological evolution,
each species plays a specific ecological role
called its niche.
Unique Roles for Species
Generalist species
Specialist species
Specialists prone to extinction
–
giant panda
Specialized Feeding Niches in Birds
Fig. 4
-
5, p. 68
Louisiana heron
wades into water
to seize small fish
Black skimmer
seizes small fish
at water surface
Ruddy
turnstone
searches
under shells
and pebbles
for small
invertebrates
Avocet sweeps bill
through mud and
surface water in
search of small
crustaceans, insects,
and seeds
Brown pelican
dives for fish,
which it locates
from the air
Dowitcher probes
deeply into mud in
search of snails,
marine worms, and
small crustaceans
Herring gull
is a tireless
scavenger
Flamingo feeds on
minute organisms
in mud
Scaup and other diving
ducks feed on mollusks,
crustaceans, and aquatic
vegetation
Piping plover
feeds on insects
and tiny
crustaceans on
sandy beaches
Knot (sandpiper)
picks up worms
and small crustaceans
left by receding tide
Oystercatcher feeds on
clams, mussels, and other
shellfish into which it
pries its narrow beak
Science Focus: Cockroaches
Existed for 350 million years
–
3,500 known
species
Highly adapted, rapidly producing generalists
•
Consume almost anything
•
Endure food shortage
•
Survive everywhere except polar regions
•
Avoid predation
Carry human diseases
4
-
4 How Do Extinction, Speciation, and
Human Activities Affect Biodiversity?
Concept 4
-
4A
As environmental conditions
change, the balance between formation of new
species and extinction of existing ones
determines the earth’s biodiversity.
Concept 4
-
4B
Human activities decrease the
earth’s biodiversity by causing the premature
extinction of species and by destroying or
degrading habitats needed for the development
of new species.
Speciation
Geographic isolation
Reproductive isolation
Millions of years in slow
-
producing species
Hundreds of years in rapidly reproducing
species
Geographic Isolation
Fig. 4
-
6, p. 70
Spreads
northward
and southward
and separates
Arctic Fox
Gray Fox
Different environmental
conditions lead to different
selective pressures and evolution
into two different species.
Adapted to cold
through heavier
fur, short ears,
short legs, and
short nose.
White fur
matches snow
for camouflage.
Adapted to
heat through
lightweight
fur and long
ears, legs, and
nose, which
give off more
heat.
Northern
population
Southern
population
Early fox
population
Extinction
Endemic species
vulnerable to extinction
Background extinction
Mass extinction
Balance between speciation and extinction
determines biodiversity of earth
Speciation generally more rapid than extinction
Extinction through Habitat Loss
Fig. 4
-
7, p. 70
Human Activities and Extinction
Cause premature extinction of species
Earth took millions of years to recover from
previous mass extinctions
4
-
5 How Might Genetic Engineering
Affect the Earth’s Life?
Concept 4
-
5
Genetic engineering enables
scientists to transfer genetic traits between
different species
–
a process that holds great
promise and raises difficult issues.
Humans Change Population Genetics
Artificial selection
–
slow process
Selective breeding
Crossbreeding
–
not a form of speciation
Genetic engineering
Results of Genetic Engineering
Genetically modified organisms
(
GMOs
)
Gene splitting rapid vs. artificial selection
Modified crops, new drugs, fast
-
growing animals
Steps in Genetic Engineering (1)
Steps in Genetic Engineering (2)
Fig. 4
-
8, p. 72
Fig. 4
-
8a, p. 72
Phase 1
Gene Transfer Preparations
Host cell
Enzymes integrate plasmid
into host cell DNA.
A. tumefaciens
(agrobacterium)
Agrobacterium takes up plasmid
Foreign gene integrated into
plasmid DNA, which can be
used as a vector
plasmid
Extract
plasmid
A. tumefaciens
Plant cell
Foreign gene
if interest
Extract DNA
Phase 2
Make Transgenic Cell
Fig. 4
-
8b, p. 72
Phase 3
Grow Genetically
Engineered Plant
Foreign DNA
Host DNA
Nucleus
Transgenic
plant cell
Cell division of
transgenic cells
Cultured cells
divide and grow
into plantlets
(otherwise
teleological)
Transgenic plants
with desired trait
Pros and Cons of Genetic Engineering
Pros
•
May help cure genetic defects
•
May improve organisms
•
May lead to development of secondary evolution
Cons
•
Ethical issues
•
Privacy issues
•
Designer babies
•
GMO crossbreeding with original organisms
Genetically Engineered Mice
Fig. 4
-
9, p. 73
Animation: Carbon Bonds
Animation: Stanley Miller’s Experiment
Animation: Evolutionary Tree of Life
Animation: Stabilizing Selection
Animation: Disruptive Selection
Animation: Moth Populations
Animation: Adaptive Trait
Animation: Speciation on an Archipelago
Animation: Evolutionary Tree Diagrams
Animation: Gause’s Competition Experiment
Animation: Species Diversity By Latitude
Animation: Humans Affect Biodiversity
Animation: Habitat Loss and Fragmentation
Animation: Transferring Genes into Plants
Video: Ancient Human Skull
PLAY
VIDEO
Video: Asteroid Menace
PLAY
VIDEO
Video: Bachelor Pad at the Zoo
PLAY
VIDEO
Video: Cloned Pooch
PLAY
VIDEO
Video: Creation vs. Evolution
PLAY
VIDEO
Video: Dinosaur Discovery
PLAY
VIDEO
Video: Glow
-
in
-
the
-
Dark Pigs
PLAY
VIDEO
Video: Hsing Hsing Dies
PLAY
VIDEO
Video: Mule Clones
PLAY
VIDEO
Video: New Species Found
PLAY
VIDEO
Video: Penguin Rescue
PLAY
VIDEO
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