Transcript adaptation - SCHOOLinSITES

The Theory of Evolution
Chapter 15
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Charles Darwin and Natural Selection
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
The theory of evolution is the fundamental
concept in biology…… Evolution describes the
theory of change in populations over time, not
individual species.
Charles Darwin (1809 – 1882)
Fossils shaped ideas: Why have
some species become extinct?

How are extinct species and
modern species related, if they are?
 Darwin spent years studying and trip to Galapagos
Islands and wrote “On the Origin of the Species”

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Artificial and Natural Selection
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•
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Darwin observed breeding organism with a
certain trait produced offspring with identical
traits. This is called artificial selection.
Examples:
Darwin decided that there must be a similar
process in nature. He called this
natural selection.
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Successful (adaptive)
genotypes become more
common in subsequent
generations, that leads to
increase in fitness
(increase in the ability to
survive)
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Natural selection: organism with favorable traits
are able to reproduce and pass their traits on
to their offspring.
• Those without favorable traits are more likely
to die and those with the favorable trait would
be favored.
Which moths
are more likely
to survive?
Light moths
Dark moths
Light tree
Dark trees
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Charles Darwin and Natural Selection
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•
Fossils Shaped Darwin’s Ideas
Scientist wondered how fossils formed and why
many fossils species were extinct.
What kinds of relationships might exist between
the extinct and modern species?
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Darwin on HMS Beagle
•
At 22 took job as naturalist on English
ship as Naturalist. (5 year scientific journey)
•
Collected biological and fossil specimens
•
Became curious about possible relationships among
species…foundations of theory of evolution and Natural
Selection
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•
Evidence for Evolution
An adaptation is any variation that aids an
organism’s survival in its environment.
Examples of adaptations
Mimicry: occurs when one species looks like
another species. A harmless species takes on the
look of a dangerous species. Predators avoid the
harmful and harmless species. Both benefit.
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Mimicry Is An Outcome of Predator-Prey Interactions
If a potential prey species develops an effective defense system,
other unprotected prey species may come to mimic the
protected species.
The stinging yellow jacket and its harmless mimic, the
clearwing
moth.
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Mimicry
Disturbed hawkmoth larva.
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Snake
•
Camouflage: an adaptation that enables
species to blend with their surroundings
VideoPraying
Mantis
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Camouflage in the Anglerfish
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Other evidence:
Video: Whale fossils
Fossils:
•
Paleontologist conclude from fossils that
the ancestors of whales were probably landdwelling, doglike animals, but the record is
incomplete. They do not have all the fossils
for all the changes but still draw conclusions
as to the overall picture.
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Structurally Similarities
Homologous Structures:
The anatomy of different
organism show similar
patterns. Some believe
these structural features
show common origin.
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•
Bird and butterfly wings are not similar in
structure, but they are similar in function
(what they do - Function).
The body parts of organism that do not have a
common evolutionary origin but are similar in
function are called analogous structures.
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Vestigial structure:
•
A body structure in a present-day body organism that NO
longer serves its original purpose, but was probably useful
to an ancestor. Examples:
–
eyes of blind mole-rats are vestigial
–
cave fish are vestigial
–
flightless birds (ostrich)
–
pelvic bones in whales
– An adult python pelvic legs can be seen
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Convergent: unrelated organism evolve
similar traits because they live in similar
environments
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Divergent: Occurs as populations that
were once similar to an ancestral
species change and adapt to different
living conditions.
Kit Fox
Red Fox
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Adaptive radiation
•
Is a type of Divergent evolution in which
ancestral species evolve into a variety of
species that fit diverse habitats. (Galapagos
Islands)
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Darwin’s Finches- Adaptive Radiation
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•
These finches, better known as 'Darwin's
Finches' illustrated adaptive radiation. This
is where species all deriving from a common
ancestor have over time successfully
adapted to their environment via natural
selection.
Previously, the finches occupied the South
American mainland, but somehow managed
to occupy the Galapagos islands, over 600
miles away. They occupied an ecological
niche with little competition.
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Bird Beak Adaptation
Brown
Creeper:
Thin bill
curves down
to probe under
bark
Cardinal, Gross
Beak:
Beak is used as a
nut cracker to crack
open nuts and seeds
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Curlew: Long
downward curved beak
to probe shores for
worms in the sediment
Bird Beak Adaptation
Heron: spear like
bill for spearing
fish and frogs.
Eagle: Short stout
beak, hooked upper
jaw for tearing
flesh.
Flamingo: short
downward snout
for separating
mud and silt from
shellfish and
algae to eat
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Bird Beak Adaptation
Duck Merganser:
Flat Sieve like bill
for drinking and
catching fish
Pelican: large bill
with a stretchable
pouch for holding
fish caught under
water.
Hummingbird.
Uses long bill to
dipping in flowers
and sipping nectar
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Bird Beak Adaptation
Woodpecker:
uses its beak like
a drill to bore
holes in bark to
get at the insects
Spoonbill:
to shovel small
fish and
crustacean
from the mud
Skimmer: use
lower jaw to skim
water to scoop fish
from the water.
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Hibernation:
Some mammals, such as bats and chipmunks, and a few
other types of animals go into a deep sleep during parts of the
winter months.
• state in which body temperature drops substantially
• oxygen consumption decreases
• breathing rates decline to a few breaths per minute
• Conserves __________,
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Hibernators
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Migration:
Instinctive, seasonal movement of animals.
• In North America, about 2/3 of birds species fly south in
fall to areas such as South America.
• Migration generally occurs to places where breeding occurs
in the summer
• Migration occurs to where food is available during the
winter
• Whales migrate seasonally
• Migration might be responding to colder temperatures and
shorter days
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Migration
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Migration
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Migration
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Continental Drift and Geographic Isolation
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•
The theory that Africa and South America
slowly drifted apart and were once a single
landmass.
The monkeys on the two continents, although
similar have many genetic differences. This is
called geographic isolation. Occurs
whenever a physical barrier such as a river
divides a population; results in individuals of
the population no longer able to mate- this can
lead to new species
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Question 1
Which example BEST describes mimicry?
A. Moving to a new location to obtain food
B. Appearing to look like a different animal
C. Catching prey with sharp teeth
D. Keeping warm with thick fur
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Question 2
Animals hibernate for many reasons. What is on reason animals
would NOT hibernate?
A. To conserve energy
B. To avoid harsh climate conditions
C. To locate prey
D. To survive when food is hard to find
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Question 3
Which statement describes how some animals may adapt to an
environmental change?
A. Urbanization causes some birds to mimic other birds.
B. Deforestation causes some birds to change their beak
shape.
C. Natural disasters cause some mammals to hibernate.
D. Seasons cause some mammals to change fur coloration.
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Question 4
Study the two animals below.
The hoverfly and the wasp have similar coloration and physical
characteristics. However, only the wasp can defend itself by
stinging potential predators. Which type of protective adaptation is
demonstrated by the hoverfly?
A. Stinger B. Mimicry C. Camouflage D. Counershading
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Question 5
Which statement describes an organism’s behavioral adaptation?
A. A chameleon changes its body coloring to blend into its
environment
B. An elk has four-chambered stomach to help digest the foods
it eats.
C. A shark has a light-colored belly and a dark top side to
camouflage it in its habitat.
D. A trumpeter swan has a sharp beak so it can dig for roots
underwater.
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Question 6
Study the picture below. For which activity is this bird’s beak best
adapted?
A. Tearing flesh
B. Spearing fish
C. Sipping nectar
D. Chiseling wood
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Question 7
Study the picture below. For which activity is this bird’s beak best
adapted?
A. Tearing flesh
B. Spearing fish
C. Sipping nectar
D. Chiseling wood
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Question 8
Study the picture below. For which activity is this bird’s beak best
adapted?
A. Tearing flesh
B. Probing Shoreline for worms
C. Sipping nectar
D. Chiseling wood
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Question 9
Study the picture below. For which activity is this bird’s beak best
adapted?
A. Spearing fish and frogs B. Probing Shoreline for worms
C. Sipping nectar
D. Chiseling wood
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Question 10
Study the picture below. For which activity is this bird’s beak
best adapted?
A. Chiseling wood B. Shoveling and Scooping mud
C. Cracking nuts open
D. Tearing flesh
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Question 11
A walking stick is an insect that
resembles a stick or branch of a plant.
What is the BEST description of this
protective adaptation?
A. The walking stick is attracting a
mate
B. The walking stick is searching for
food
C. The walking stick is preparing for
hibernation
D. The walking stick is camouflaging
itself from predators.
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Question 12
Some species of lizards change their body colors to resemble
their environment, inflate their bodies or throats, or secrete
substances to mark territories. Which of these protective
strategies is NOT an adaptation of the lizard?
A. Migration
C. Physical change
B. Camouflage
D. Chemical defense
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