1. EVOLUTION AND BIODIVERSITY
CHAPTER 4

2. FACTORS effecting BIODIVERSITY
EVOLUTIONARY PROCESSES (MICRO VS. MACRO)
MUTATIONS
NATURAL SELECTION
SPECIES FORMATION
SPECIES EXTINCTION

3. EVOLUTION: change in a population’s genetic makeup
HYPOTHESES:
CHEMICAL EVOLUTION VS. BIOLOGICAL EVOLUTION

4. © 2004 Brooks/Cole – Thomson Learning
Formation
of the
earth’s
early
crust and
atmosphere
Small
organic
molecules
form in
the seas
Large
(biopolymers)
First
protocells
Single-cell
prokaryotes
eukaryotes
Variety of
multicellular
organisms
form, first
in the seas
and later
on land
Chemical Evolution
(1 billion years)
Biological Evolution
(3.7 billion years)
© 2004 Brooks/Cole – Thomson Learning

5. FACTORS effecting BIODIVERSITY
I. EVOLUTIONARY PROCESSES
A. MICRO—small genetic changes in populations
(1) MUTATIONS (some harmless, some harmful); are random and unpredictable
(2) Leads to NATURAL SELECTION
(3) Individuals of a popl. Have genetically based traits that increases their survival---ADAPTATION
EXAMPLE: Peppered moth

6. NATURAL SELECTION
“PEPPERED MOTH”
Mutations/genetic changes caused natural selection to occur. Color form (2 types) was genetically based, causing greater survival due to environmental changes.

7. EVOLUTIONARY PROCESSES continued
B. MACRO-long-term, large scale changes
(1) New species formed=SPECIATION
a. Caused by geographic isolation: groups of the same species become physically separated
b. Caused by reproductive isolation: mutations and natural selection operate independently in two geographically isolated populations
So different, can’t breed or produce live young
One species becomes two through divergent evolution

8. Speciation… leads to….Geographic isolation and Reproductive isolation
Adapted to heat
through lightweight
fur and long ears,
legs, and nose, which
give off more heat.
Adapted to cold
through heavier
fur, short ears,
short legs, short
nose. White fur
matches snow
for camouflage.
Gray Fox
Arctic Fox
Different environmental
conditions lead to different
selective pressures and evolution
into two different species.
Southern population
Northern population
Spreads
northward
and
southward
separates
Early fox
population
leads to….Geographic isolation and
Reproductive isolation

9. EVOLUTIONARY PROCESSES continued
(2) Species Extinction
(a) if species can’t adapt, move, or cease to exist when environmental conditions change
(b) causes of extinction
habitat loss, overhunting, invasive species

10. Other factors relating to adaptations to the environment
Ecological niche
“way of life” or functional role a species plays in it’s environment
different from habitat (physical location)
2 categories:
(1) Generalist species: broad niches
eat a variety of foods, wide range of tolerance
ex: cockroaches, mice, rates, raccoons, coyotes, humans

11. (2) Specialist species: narrow niches
Live in only 1 habitat type
Eats specialized food
Narrow range of tolerance
Prone to extinction
Ex: spotted owls,
giant panda, koala