Ch. 14 Evolution lution : he process of change that produces new pecies from already existing species. hange in a species due to mutation of the NA code that occurs over a long time. evolution: generation-to-generation change in the proportion of different inherited genes in a population that account for all of the changes that have transformed life over an immense time.
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Ch. 14 Evolution Evolution : the process of change that produces new species from already existing species. Change in a species due to mutation of the.
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Ch. 14 Evolution
Evolution : • the process of change that produces new
species from already existing species.• Change in a species due to mutation of the
DNA code that occurs over a long time.
evolution: generation-to-generation change in theproportion of different inherited genes in a population that account for all of the changes that have transformed life over an immense time.
Species – group of closely related organisms that can mate and produce fertile offspring.
Adaptation: inherited characteristicthat improves an organism's abilityto survive and reproduce in a particular environment.
Evolution of Air Breathing:
Evolution of Brains:
Early Ideas about Evolution
Originally people thought that the species on Earth were permanent – the same species had always been here.They also thought that the Earth wasn’t that old – lessthan 10,000 years old.
In the 1700’s, people began to find fossils.
The discovery of fossils meant the Earth might be much older than thought.
It was also noted that the fossils were different fromknown living creatures, and that different living specieswere often similar to each other while not being exactly the same.
Lamark’s early theory of evolution
Lamark had the idea that specieschange over time.
Evolution involvesadaptations
Lamark’s Theory
•Species adapt because of what they need or want.•Use of structure results in evolution –
called “acquired characteristics”.•acquired characteristics are passed on
to next generation.
Lamark’s theory is no longer accepted, but he was the first to suggest that evolution occurs and that it is related to adaptations.
Darwin’s Theory of Evolution
1859 - Charles Darwin publishes The Origin of Species.
Darwin’s Voyage on “Beagle” shaped many ideas of Biology
Purpose of voyage – Sail around world & survey little known coastal areas
HMS Beagle Voyage 1835
Charles Darwin
Natural Selection:“Survival of fittest”Competition for resourcesBest adapted species surviveThe Fittest reproduce
natural selection: process by which individuals with inheritedcharacteristics well-suited to theenvironment leave more offspringthan do other individuals
Darwin’s key ideas:
• A. REPRODUCTION: Organisms produce more offspring than can survive
• B. VARIATION:Variety in traits exist• C. SURVIVAL OF THE FIT: Some traits
allow survival & are passed on• D. Over time certain variations make up
most of a population & they may be different from their ancestors