WHAT ARE ADAPTATIONS?
Good Fit!
NOT
On the Other Hand…
Some organs that many animals share CAN be considered an adaptation if they perform a relatively unique function.
• For example, the human appendix is a small, useless organ with no real function.
This is true for many mammals.
WHAT PROMPTS ADAPTATIONS IN A
POPULATION?
Short-Term Environmental Changes
•
Occur as a
result
from a
catastrophic event or
other environmental
change
•
(ex: hurricane, volcano,
drought, new predator)
Long-Term Environmental
Changes
•
Occur as a result of a
change that occurs over
centuries to
millions
of
years.
•
(ex: climate change,
GIVE ME AN EXAMPLE!
Kaibib Squirrels
•
The squirrels
used to be part of
the same species of squirrel
and interbred, but as the
Grand Canyon formed the
squirrel s lost the ability to
interbreed with one another
and became their own species
of squirrel.
AND ANOTHER EXAMPLE!
For thousands of years, the pepper moth lived in forests where the trees were covered in LICHEN.
Notice that the dark moths really stood out and were very few in number. The white ones blended in with the crusty lichen.
Then people started building industrial plants that polluted
WHY DO ADAPTATIONS OCCUR?
Organisms must be best
fit for their environment
to
survive
and
reproduce
successfully!!!
Natural Selection- the process by organisms with the best suited traits survive and reproduce and pass their successful traits to their offspring
This is called….
TWO TYPES OF ADAPTATIONS
Structural Adaptations
•
physical
features of an
organism that allow them
to survive in an area
successfully
Behavioral Adaptations
•
behaviors
which allow
STRUCTURAL ADAPTATIONS
Poison & Venom – How’s it help???
STRUCTURAL ADAPTATIONS
Horns & Thorns– How’s it help?
DEFENSE MATING RIGHTS DEFENSE
COMPETITION DEFENSE (we think)
DON’T EAT ME
STRUCTURAL ADAPTATIONS
Claws & Fangs – How’s it help?
Not just for killing Not just for killing
Not just for
killing Uh, for killing Killing
Killing
Uhhh… duh
STRUCTURAL ADAPTATIONS
Armor – How’s It Help?
Now what, chump?
Nice try, kid
Armor or just heat vents?
STRUCTURAL ADAPTATIONS
Bad taste/smell – How’s it help?
Milkweed
STRUCTURAL ADAPTATIONS
Camouflage & Mimicry – How’s it help?
(octopus)
(pipefish)
Spotted for owls
BEHAVIORAL ADAPTATIONS
Flight – How’s it help?
Didn’t think of that, did you?
Good luck, dude!
BEHAVIORAL ADAPTATIONS
Speed – How’s it help?
~40 mph ~45 mph
~50 mph ~60 mph
~65 mph ~70 mph…yeah baby!
250+ mph ~25 mph
BEHAVIORAL ADAPTATIONS
Check THAT out, turkey.
Courtship Displays – How’s it help?
Adaptations- It’s not just for Animals…
Adaptation – a physical structure, behavior, or skill that provides an organism a better chance at surviving & reproducing
Organism means a living thing, so don’t forget that non-animals,
such as plants, and even tiny one-celled organisms and bacteria also have adaptions.
NATURAL
SELECTION
The unequal survival and reproduction of
organisms due to environmental forces,
resulting in the preservation of
favorable
adaptations.
It is a two step process:
1. The Production of variation in a population
2. Non-random aspects of survival and
Bred Pigeons came from a single
original species
Humans select traits for dogs, pigeons and other
animals when they breed them.
INDIVIDUALS THAT HAVE TRAITS THAT ARE BEST
ADAPTED FOR THE CURRENT ENVIRONMENT ARE THE
ONES THAT SURVIVE TO BREED AND PASS ON THEIR
GENES TO THE NEXT GENERATION.
Organisms not possessing the beneficial
traits either die or don’t have as many
offspring.
Natural Selection is Survival of
the fittest
Natural Selection is a mixture of both Chance and
necessity
What acts as a selection
pressure on a population?
•
Competition for
food
•
Competition for a
mate
•
Changes
in the environment
•
Predators
MAIN TYPES OF SELECTION
PRESSURES
•
Directional Selection
Natural selection favors one extreme of the
population for that trait
often happens when environment changes in a
consistent way- e.g.climate gets colder.
•
Disruptive Selection
Natural selection favors both extremes selected
Causes species to diverge
•
Stabilizing Selection
Natural selection favors the average for population
selected
DIRECTIONAL SELECTION: MIMICRY
STABILIZING
SELECTION
•
When the extremes
of the trait
aren’t
as well suited
Examples
•
bird clutch size
•
Elk Antlers size
DISRUPTIVE
SELECTION
•
Causes a dip within the
species
•
Occurs when
two
different
types of
resources in one area
•
Results in
specialization for each
branched group
•
May lead to formation
of new species
•
E.g. Darwin’s Finches
EXAMPLES OF SELECTION
PRESSURES...
•
Predators
-
variants with adaptations allowing them to escape predators have more offspring- e.g. speed, defensive weapons, camouflage, mimicry
•
Prey/Food
- variants with adaptations allowing them to obtain food have more offspring- e.g. Speed, senses for finding prey/food, weapons for killing prey or obtaining food, camouflage for stealth
•
Climate
- those who can survive new climate best have more kids- e.g. ice age, change in climate due to migration.
