1. “AGE OF FISH”
INTERNAL FERT DEVELOP

2. So what is biological evolution?
Successive genetic changes in a species over many generations.
New species result as genetic characteristics are modified; due to:
Mutation: change to DNA(random, predictable)
Isolation: events that separate populations
New allele combinations: results in variation w/in populations
Reproduction: sexual/asexual, rates
Environment: is it constant? or changing?
Implies natural processes are at work

3. SELECTIVE BREEDING results in ARTIFICIAL SELECTION
Humans have been manipulating the genetics of populations since we first began domesticating animals and plants
SELECTIVE BREEDING results in ARTIFICIAL SELECTION
Rather than allowing natural events to determine WHICH combinations of genes ARE SUCCESSFUL; we select THE specific traits to combine TO ACHIEVE A DESIRED RESULT
This process HAS resulted in new varieties of
dogs, cats, horses, pigs, chickens, tomatoes, corn, etc

4. Evolutionary theory suggests the same genetic mechanisms are at work in nature…but through Natural Selection

5. History of Evolutionary Thought
Jean –Baptiste Lamarck( )
Theorized that acquired traits can be inherited.
Environmental change
causes changes in the needs of organisms
Changing needs causes changing behavior
Altered behavior leads to changes in the use of a structure
Greater use- structure gets larger
Less use-structure gets smaller or disappears.

6. Lamarck did see that organisms do change over time; that the
environment drives the change…
however, his “use/disuse” mechanism is completely WRONG!!!

8. Thomas Malthus( )
Was a political economist who studied population dynamics Observed that animals and plants produced far more offspring than can survive. Populations will grow to a size that can be supported by the environment. He related these concepts to human populations as a factor influencing poverty and famine. Darwin and Wallace related these concepts to natural selection… .

9. Alfred Wallace(1823-1913) 19th century's leading expert on
the geographical distribution of
animal species.
Best known for independently proposing a theory of species evolution by natural selection that prompted Charles Darwin to publish his own theory.
However, both men collaborated on the initial
publication of the theory.

10. Noted that natural barriers like water, mountains, canyons etc, resulted in greater diversity in populations.
Observed that similar environments result in similar adaptations even though populations have different geographical origins.

11. OSTRICH EMU RHEA
AFRICA AUSTRALIA S AMERICA
Wallace theorized the birds have similar structures because their environments are similar, resulting in the same demands on the species for survival

12. Charles Darwin( )
Developed and published a unified theory of evolution by natural selection in 1858 Based upon observations made in South America and the Galapagos Islands in 1835

13. Darwin’s Observations
It’s a struggle to survive: species must compete for food, space, water, mates, etc

14. All living organisms over produce: (incorporated from Malthus)

15. There is natural variation within species: genetic differences exists w/in organisms of same species
raw
material for
adaptation

16. Two main aspects of the Theory
DESCENT WITH MODIFICATION
Newer species appear to be descended from older species
Species may be descended from one or a few original species

17. Please begin cutting…
Place all the #1 pieces into a pile with the #1 heading Explanations
Place all the #2 pieces into a pile with #2 heading Example
Pieces are numbered on the back

18. EVOLUTIONARY THEORY

19. Environment determines which traits are successful: eventually they become adaptations

21. NATURAL SELECTION Mechanism for divergence
Characteristics of the environment “select” traits that increase a population’s ability to survive Those organisms with favorable traits (adaptations) are best suited and are more likely to survive to reproduce and pass those traits to offspring giving them an adaptive advantage. Those that do not possess favorable traits more likely to die thus not reproduce and remove those traits from gene pool Over time organism’s variation increases from the original population, the species has diverged genetically or evolved.
CALLIOPE

22. Necking for
Repro rights
More won battle
To reproduce

23. Little Genetic Variation
Very Specific Diets
Limited Habitats
Slow Reproductive Rates
*Human influences

24. Greater Genetic Variation
Non-Specific Diets
Unlimited Habitats
Faster Reproductive Rates

25. Take into consideration…
The following genetic events randomly affect an organism’s characteristics; thus affecting evolutionary changes, if any, that may occur:
Mutation(any change to DNA)
Degree of variation in the population
Recombination of genes through sexual reproduction
Independent assortment of alleles(genes) in meiosis
Isolation/Separation of populations(genetic drift)
The rate of environmental change directly affects selection(stable-little change, unstable- more change, or extinction)
Generally, the more complex(amt of coding DNA) the organism the slower the process:
bacteria: single strand DNA-many generations
very short time, greater change(resistance)
elephants: lots o’ DNA- few generations in very
long time(2 yrs to make 1!), less change

26. STEPS EXPLANATION EXAMPLE
Variation is the raw material for natural selection
Every species contains genetic variation: mutation, crossing over, etc
Living things must struggle to survive
Produce more than can survive, must evade predators, compete for living space, food
Only some will survive to reproduce
Some survive better than others. These are more likely to produce offspring
Natural selection causes genetic change in population
Each generation has more successful organisms.
Species adapt to their environment
Selection tends to make a population better suited to its environment.