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A Species overproduce offspring that may survive an environment B There is little variation among members of a population C Competition for resources mates and space among species leads to a struggle to survive ID: 711560 Download Presentation
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Presentation on theme: "Natural Selection Natural Selection 3 Facts, 1 Lie"— Presentation transcript
Slide1
Natural SelectionSlide2
Natural Selection 3 Facts, 1 Lie
A. Species overproduce offspring that may survive an environment.
B. There is little variation among members of a population.
C. Competition for resources, mates, and space among species leads to a struggle to survive.D. Successful individuals reproduce and pass favorable traits to the next generation.
What are the 4 key components of natural selection?
What kinds of limited resources can create a struggle between individuals in a population? What kinds of variable traits within a population might natural selection act upon? How does natural selection affect the genetic variation within the next generation of the same population?
LIE
4 Parts of Natural SelectionSlide3
Natural Selection
The driving mechanism behind evolution, as explained in Darwin’s
Origin of Species
Certain organisms survive to pass on their traits to successive generations, but most do not.
Often summed up as “survival and reproduction of the fittest”I. Natural Selection
Charles DarwinSlide4
A. Charles Lyell
Presented
evidence that the Earth had formed by natural processes over a long period of time.
II. Darwin’s InfluenceSlide5
B. Thomas Malthus
Populations are limited by predators, disease, and food supply.Slide6
C. Artificial Selection
Selective breeding, or “artificial selection” is the same process that has led to all the variation we see in dog breeds today.
In artificial selection, humans speed up the
change in traits by
doing the selecting
themselves. In
natural selection, nature itself is doing the selecting over thousands of generations.Slide7
The
mechanism
(driving force) for evolution, as explained by Charles Darwin.Explains changes in an entire species or population (not individuals) over time.
Darwin knew this
Natural Selection
2) Mutations
Random changes in DNA are sometimes passed on to offspring.
Some helpful; some harmful; some neutral
Only traits that
increase reproductive fitness
will continue to be passed on.
Darwin didn’t know this because he didn’t know about…
III. Evolution of SpeciesSlide8
IV. 4 Parts of Natural Selection
Overproduction
More young are produced that can survive.Slide9
IV. 4 Parts of Natural Selection
Inherited Variation
-
Small differences within a population.
Ex: height, color, etc.Slide10
IV. 4 Parts of Natural Selection
3) Struggle to Survive
-
Some variations are favorable and improve the
ability to adapt. Slide11
IV. 4 Parts of Natural Selection
4
) Successful Reproduction
-
Those that survive reproduce and pass down
favorable traits.