Adaptations & Natural Selection
NICHE
• A habitat supplying factors
necessary for existence of
an organism and its
ecological role in regard to
food consumption.
Polar Bear-fur
• Lives:
– Cold environment
• Why?
– Blend in for
hunting and
protection
• Job:
– Keep population
of seals down
Woodpecker-long narrow beak
• Lives:
– In a tree
• Why?
– Safe from
predators
• Job:
– Control insect
population that
harms trees
ADAPTATION
• A characteristic that helps
an organism survive and
reproduce.
–Survive means: eat, blend,
hunt, protect self, find food,
etc.
DESERT FOX
•
Hot
environment
• Big ears
• Little to no
fur short
hair
ARCTIC FOX
•
Cold
environment
• Small ears
• Heavy
thick fur
DESERT
RABBIT
•
Hot
environment
• Big ears
• Little short
haired
ARCTIC HARE
•
Cold
environment
• Small ears
• Heavy
thick fur
BIG IDEA
Heat escapes through the ears
Fur traps heat
Adaptations
• Bioluminescence
– Light that is given off
by a creature
• Lightening bugs
• Angler fish
• Mushrooms in Brazil
Adaptations
• Echolocation
– An animal’s (or human’s)
ability to tell where an
object is by detecting
the sound bouncing off
of it
– Bat, dolphins
Adaptations
• Flippers
– Legs that are specialized
for swimming
• Sea turtles
• Ducks
• Walrus
Adaptations
• Claws
– Used for gripping,
digging and
tearing things
apart
• Bears
• Moles
• Cats
Adaptations
• Teeth
– Used for tearing, chewing,
ripping food for consumption
– Sharp
• Lion
• Eating Meat
– Flat
• Horse
• Grass/Grains
– Baleen (filter-like)
• Blue Whale
• Krill
– Mixed
• Humans
• Meat and plants
Adaptations
• Smell
– Ability to detect
scent to find food,
a mate, or avoid
danger
• Vultures
• Turkey
• Dogs
Another Adaptation
• Asexual reproduction
– A form of reproduction without a mother and a
father; genetically identical to its parent (like a
clone)
– Strawberries plants will make runners, vines that
will root and make a new plant
– A potato will sprout and produce new potato
plants
Fungi make spores that will explode off
of themselves and make new fungi.
Black bread
mold grows on
bread
Black bread
mold produces
spores
Black bread mold
spores spread over
surface of bread
and continue to
grow more
Natural Selection
• Process by which
individuals that are
better adapted to their
environment are more
likely to survive and
reproduce than other
members of the species
– Therefore, they pass on
the more desired traits
for survival
Natural Selection
• Its theorized that giraffes adapted
to the climate change in Africa
when it went from being a lush
jungle to a drier savannah over
two million years ago.
• Normal food sources died out.
Trees became the main food
source, with leaves high up.
• Offspring that were born with
shorter necks could not reach the
food and did not survive.
• Only the giraffes with the longer
necks were able to survive and
reproduce, so the giraffe
population passed on the long
neck gene to its offspring.
Basic Concepts of Natural Selection
• Individual living things are different from each
other. This is called variation.
• Variation is important because without it,
populations cannot evolve over time.
• Living things produce more offspring than can
survive, and many that survive do not
reproduce.
• Living things compete for limited resources,
such as food and shelter.
Natural Selection
• Factors that affect the process:
– Overproduction
– Variation
– Competition
– Selection
– Environmental Change
– Genes and Natural Selection
Variation
• An inherited trait that makes an individual different
from other members of its species; an adaptation is
a variation that makes an organism better suited to
its environment.
• Causes of variations:
• 1. Environmental factors can cause changes in
source of genes.
• 2. Geographic isolation can make two populations so
different they become different species.
•
http://www.pbs.org/wnet/nature/lessons/the-birds-and-the-beaks/video-segments-extraordinary-birds/1481/
Variety
Competition
• Whenever two niches overlap, competition
ensues between organisms.
• If two organisms have the same requirements
- for food, water, nesting sites, whatever
(resources) - there will not be enough of that
thing to go around
http://video.nationalgeographic.com/video/animals/mammals-animals/bears-andpandas/bear_grizzly_wolves/
Overproduction
• Most species produce far more
offspring than can possibly survive.
Why?
• Environmental Conditions
• Predators
• Diseases
• Preservation of the Species
Environmental Change:
• A change in the species environment can
affect on the organism’s ability to survive
leading to natural selection.
• Ex. Monkey flowers do not normally grow in
soil high in copper concentration; because of
genetic variation some varieties have been
found growing near copper mines.
Genes and Natural Selection:
• Will have to add on the notes I left this off
• Variations result from the shuffling of the
genes when the egg and sperm join
(fertilization)
• Only traits that are inherited may be passed
down to the offspring and can be acted upon
by natural selection.
Evolution
•Change in inherited
characteristics of a
species over time.
Theories
• Scientific theory: well-tested concept or
explanation not proven
– Jean Baptiste de Lamarck
– Charles Darwin
Lamarck
Lamarck's Theory of Evolution:
Darwin was not the first person
to propose a theory of
evolution.
In the early 1800s, a wellknown French naturalist named
Jean-Baptiste Lamarck also
developed a theory of
evolution.
•He introduced the idea that the environment
caused changes in animals and these changes
were inherited by the animals' offspring.
•changes in an organism during its lifetime could
be passed on to its offspring.
•if an organism that used certain organs more
than others, then the organ used the most would
evolve.
• For example, Lamarck thought that giraffes
could stretch their necks to feed on the leaves
of tall trees. These giraffes would have
offspring with long necks.
• He called this the hypothesis of use and
disuse.
• This idea is often called "the inheritance of
acquired characteristics," or "soft
inheritance," and it is now known to be
incorrect.
• Changes in an organism cannot be passed
onto its offspring unless they are controlled by
genes.
Charles Darwin
http://www.sciencechannel.com/videotopics/earth-science/galapagos-beyonddarwin-charles-darwin.htm
H.M.S. Beagle
Darwin
• Darwin observed that species of finches
on islands off the coast of South America
looked similar to a mainland species of
finches
• He hypothesized that plants and animals
on the islands originally came from South
America
http://www.pbs.org/wgbh/nova/evolution/explore-galapagos.html
• Darwin reasoned that members of a
population best able to survive and
reproduce will pass their traits to the
next generation; over time
• Resulting in a different (separate) species
• Darwin saw similarities but could not
explain WHY they existed.
Darwin
• His hypothesis became known as a
theory of evolution by natural selectionorganisms with traits suited for the
environment will more likely survive and
reproduce
http://www.pbs.org/wgbh/nova/evolution/darwin-never-knew.html
http://videos.howstuffworks.com/science/evolution-of-life-videosplaylist.htm#video-29147
• Fossils- the preserved remains
of an organism that had died
long ago.
• Darwin saw the fossil bones of
organisms that had died and
was puzzled by some of them,
such as the fossil bones that
resembled living sloths. These
were much larger than those
that were still living. He
wandered what had
happened to the giant
creatures of the past.
Fossils
• Fossil records show extinct organisms
• Showed similarities to living organisms
• Hypothesized current organism
descended (came from) from the
fossilized organism
http://videos.howstuffworks.com/discovery-health/4911-100-greatest-discoveries-evolution-video.htm
Species
• A group of
• They also have
organisms that
to be able to
share traits
reproduce
(characteristics) • Way to survive
that may be
similar.
• Adaptation: A change in an organism over time
that helps it to survive and reproduce in its
environment.
• Biodiversity: The variety and complexity of life
on Earth.
• Camouflage: Appearance that is designed for
hiding in the environment.
• Competition: Living things striving for food,
living space, mates, and other resources.
• Evolution: The process whereby new species
arise from earlier species by accumulated
changes. Often referred to as “change over
time.”
• Fitness: The ability of a living thing to survive
and reproduce in its environment.
• Natural Selection: The process by which
individuals in a population inherit genes that
allow them to survive and be reproductively
successful.
• Variation: Differences in individual living
things from each other.
• Scientific theory: well-tested concept or
explanation not proven
• Fossils- preserved remains of animals that
died long ago
• Genetic Diversity-
Vocabulary
– Difference in the genes among a species
• If every human was exactly the same and an infectious, deadly disease came
around, what would happen???
• Variations– Any difference between individuals of the same species
• Resilient– Able to overcome a tough situation
• Continuous– Never ending; cycle
• Water cycle, carbon cycle, changes
• Migration– Movement of a species during certain times of the year
• Birds, sea turtles, monarchs
• Competition– Interaction among organisms by which they compete for survival, for
biotic and abiotic factors, reproduction, and hierarchal position.
Speed of Evolution
• Two models that explain the
speed of evolution
–Gradualism
–Punctuated equilibrium
Speed of evolution
• Gradualism
– Slow, ongoing
process
– Change may take
place through a
slow but
continuous
process
• Punctuated
equilibrium
– Gene mutation
can result in a new
species in a short
period of time