Transcript Apaptive Variation - Hicksville Public Schools

Aim: How does adaptive
variation lead to the survival
of an organism?
How is Kevin Costner different from
everybody else in Water World?
He had webbed feet and gills
ADAPTIVE VARIATION
Variation
1
DIFFERENCES (in structure and
or behavior) within a population
What produces variations?2
1. Sexual
reproduction
• recombination of
genes (fertilization)
• Meiosis
• Crossing over
What produces variations?
• Independent
assortment –
different gametes
made by one
parent
2. Mutations
Why are variations important to a
population?3
• Variation in a species
increases the
chances that some
members will survive
a significant change in
the environment.
• Why is this
important…?
For example: The peppered
moth
Adaptation
A variation (trait) that allows an
organism to survive in it’s environment
Adaptive Variation
5
A variation (trait your
born with) that allows
you to survive a
changing environment
Types of Environmental Changes
•Climate
•Food Sources / Availability
•Predators
•Available oxygen (in ponds, lakes,
bays, rivers)
•Habitat / shelter
What would happen to a population
(with variation) if the environment
changed?6
• Those who had an
adaptive variation
would survive (&
reproduce). This may
lead to ….
EVOLUTION
What would happen to a population
that did not have variation?7
• If they don’t posses a
trait that allows them to
adapt to a changing
environment, they will
decrease in population
(more die, also
reproduce less which
may lead to….
EXTINCTION
How does this affect evolution?
Evolution defined as:
1) The process by which species change
over time.
2) Present day species are related to
ancient species.
Summary Questions:
1)What are the two driving forces behind
Reproductive Variation & Environment
evolution? ______________________
2)How do variations in traits within a
species occur? Sexual Reproduction &
Genetic Mutations
3)In your own words, define what an
adaptive variation is?
Controversial- hunting or climatic changes,
that’s what happened to its ancestor, the
southern mammoth.