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Adaptations
Adaptation
• Any trait of an organism that enhances its chances
of surviving and reproducing in its environment.
Content Statement
• Diversity of species occurs through gradual
processes over many generations. Fossil records
provide evidence that changes have occurred in
number and type of species.
• Fossils provide important evidence of how life and
environmental conditions have changed.
Content Statement cont.
• Changes in environmental conditions can affect
how beneficial a trait will be for the survival and
reproductive success of an organism or an entire
species.
• Throughout Earth’s history, extinction
of a species has occurred when the environment
changes and the individual organisms of that
species do not have the traits necessary to survive
and reproduce in the changed environment. Most
species (approximately 99 percent) that have lived
on Earth are now extinct.
What is “diversity of
species”?
Species diversity refers to the measure of diversity in an
ecological community. Species diversity takes into consideration
species richness, which is the total number of different species in
a community. It also takes into account evenness, which is the
variation of abundance in individuals per species in a
community.
Communities with more species are considered more diverse
than those with fewer. A community with less variation in the
relative abundance of individuals per species is considered more
even than one with more variation. Communities that are more
even are also said to be more diverse.
The Encyclopedia of Earth
http://www.eoearth.org/view/article/156211/
Biodiversity
• 1. The number and variety of organisms found within
a specified geographic region.
• 2. The variability among living organisms on the
earth, including the variability within and between
species and within and between ecosystems.
Feature
• A structure, characteristic, or behavior of an
organism, such as eye color, fur pattern, or timing of
migration.
Trait
• The way a feature is expressed in an individual
organism, such as brown eyes, small spots, or early
migration.
Variation
• The range of expression of a feature (physiological
and/or behavioral) within a population, such as the
different eye colors, all the different fur patterns,
and all the dates on which migration starts.
• Variation is a random occurrence that takes place
during the process of reproduction.
Adaptation
• Any trait of an organism that enhances its chances
of surviving and reproducing in its environment.
Adaptations
• Physiological attributes (structures and functions) or
behaviors that enhance an organism’s opportunity
to live and reproduce in its environment.
Structural Adaptations
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Hawk’s talons
Sharks broad tail
Toad’s long, sticky tongue
Clam’s hard shell.
Functional Adaptations
• Trout’s ability to extract oxygen from water
• Skunk’s ability to produce and spray disgusting
defensive chemicals
• Bee’s ability to transform nectar into honey
• Human’s ability to reason
Behavioral Adaptations
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Squirrel’s propensity for storing nuts
Black bears long winter hibernation
Herring’s habit of schooling
Crayfish’s active territorial defense
Artic tern’s annual migration
• Changes in structure and behavior that occur
during an organism’s life cannot be passed to its
offspring.
Biological Implications
of Variations
• When factors in the environment change variation
is essential to the survival of the species. The
individuals that have structures or behaviors that
allow them to break slightly harder seeds, run a little
faster, produce broader leaves to capture more
sunshine, store a little more water, …. will have a
survival advantage over other members of the
population when the environment changes.
• As a result of natural variation in a population, the
population may survive failure of a primary food
source, invasion by a fleet predator, reduction in
solar radiation, or drought. It is important to note
that different members of the population will have
the advantage, depending on what environmental
factors imposes pressure on the population. The
result is that some members will survive to
reproduce, ensuring the survival of the species and
the continuation of the population.