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Evolution.

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Presentation on theme: "Evolution."— Presentation transcript:

1 Evolution

2 What is Evolution? How did this theory begin?
EVOLUTION is the change in populations over time. Where did Darwin make observation to consider the possibility that species change over time? GALAPAGOS ISLAND Why was the HMS Beagle important to Darwin’s studies? HE WAS THE SHIP’S NATURALISTS WHO STUDIED AND COLLECTED BIOLOGICAL SPECIMENS AT EVERY PORT

3 Types of Selection What is artificial selection? BREEDING ORGANISMS WITH SPECIFIC TRAITS IN ORDER TO PRODUCE OFFSPRING WITH IDENTICAL TRAITS NATURAL SELECTION IS A MECHANISM FOR CHANGE IN POPULATIONS. IT OCCURS WHEN ORGANISMS WITH CERTAIN VARIATIONS SURVIVE, REPRODUCE, AND PASS THEIR VARIATIONS TO THE NEXT GENERATION.

4 4 Basic Principles of Natural Selection
ORGANISMS PRODUCE MORE OFFSPRING THAN CAN SURVIVE IN POPULATIONS, INDIVIDUALS HAVE VARIATIONS. INDIVIDUALS WITH CERTAIN USEFUL VARIATIONS SURVIVE IN THEIR ENVIRONMENT *Industrial Melanism (peppered moth) OVER TIME, OFFSPRING WITH CERTAIN VARIATIONS MAKE UP MOST OF THE POPULATION AND MAY LOOK ENTIRELY DIFFERENT FROM THEIR ANCESTORS.

5 Evidence of Evolution: FOSSILS
FOSSILS shape the ideas of evolution

6 Evidence of Evolution: STRUCTURAL ADAPTATIONS
1. STRUCTURAL adaptations (morphological) A. Obvious examples- Mole-rats have large teeth and claws for digging better tunnels. B. Subtle examples: a. Mimicry – Viceroy and Monarch Butterflies; yellow jacket wasp and syrphid fly b. Camouflage 1. Cryptic Coloration- leaf frog, tree frog, chameleon 2. Counter Shading – bass c. Warning Colors – skunk, coral snake Coral snake – red on yellow will kill a fellow King Snake – red on black is a friend of Jack.

7 Evidence of Evolution: ADAPTATIONS PHYSIOLOGICAL
2. PHYSIOLOGICAL adaptations – changes in an organism’s metabolic processes. Examples: a. Bacteria have developed a resistance to the medicine penicillin. b. Insects and weeds have become resistant to the chemicals in pesticides.

8 Evidence of Evolution: BEHAVIORAL ADAPTATIONS
BEHAVIORAL adaptations – action in a species for survival. Examples a. Fish swim in schools for protections. b. Male lions fight to maintain territory.

9 Evidence of Evolution: Anatomy of Organisms
1. Homologous structures-COMMON STRUCTURAL FEATURES WITH A COMMON EVOLUTIONARY ORIGIN; SIMILAR IS ARRANGEMENT, IN FUNCTION, OR IN BOTH EXAMPLES: WHALE FORELIMB, CROCODILE FORELIMB, BIRD WING 2. Analogous structures- DO NOT HAVE COMMON EVOLUTIONARY ORIGIN, BUT ARE SIMILAR IN FUNCTION EXAMPLES - BIRD WING AND BUTTERFLY WING 3. Vestigial structures-A STRUCTURE OR ORGAN THAT SUGGEST EVOLUTIONARY RELATIONSHIP BUT HAVE NO KNOWN FUNCTION IN A PRESENT DAY ORGANISM EXAMPLES – HUMAN APPENDIX, REMAINS OF THE NICTITATING MEMBRANE ON THE HUMAN EYE

10 Evidence of Evolution: Embryology and Biochemistry
Embryology –EMBRYOS OF FISH, REPITLE, BIRD AND MAMMAL ARE MUCH THE SAME WITH GILL SLITS AND A TAIL Biochemistry – DNA AND RNA COMPARISON – USED AS THE BASIS FOR MODERN CLASSIFICATION

11 What is meant by Population Genetics?
EACH MEMBER OF THE POPULATION HAS THE GENES THAT CHARACTERIZE THE TRAITS OF THE SPECIES, AND THESE GENES EXIST AS PAIRS OF ALLELES. JUST AS INDIVIDUALS MAKE UP POPULATIONS, ALL OF THE GENES OF THE INDIVIDUALS MAKE UP THE POPULATION’S GENES.

12 What is a gene pool? ALL OF THE POPULATION’S GENES BROUGHT TOGETHER

13 What is allelic frequency?
THE PERCENTAGE OF ANY SPECIFIC ALLELE IN THE GENE POOL – HOW OFTEN A TRAIT SHOWS UP IN A POPULATION

14 What is genetic equilibrium
What is genetic equilibrium? THE FREQUENCY OF ALLELES REMAIN THE SAME IN A POPULATION FOR GENERATIONS

15 What causes changes in genetic equilibrium?
ANY FACTOR THAT DISRUPTS THE ALLELIC FREQUENCY WILL DISRUPT THE PHENOTYPE: EXAMPLES: 1. MUTATIONS – ENVIRONMENTAL FACTORS (chemicals or radiation) OR GENETIC FACTORS BY NATURAL SELECTION 2. GENETIC DRIFT – a. Small population that include the descendants of a small number of organisms: example – The Amish of Lancaster County, Pennsylvania one of the 30 settlers in this community carried the recessive genes that resulted in short arms and legs and extra fingers and toes. Today 1 in 14 have these traits rather than the 1 in 1000 in the larger population of the U.S.A. b. movement of individuals in and out of a population – Individuals leave a population, their genes are lost from the gene pool. Individuals move into population, their genes are added to the gene pool.

16 3 types of Natural Selection that Act on Variation
A. STABILIZING SELECTION FAVORS AVERAGE INDIVIDUALS IN A POPULATION AND REDUCES VARIATION IN A POPULATION. B. DIRECTIONAL SELECTION FAVORS ONE OF THE EXTREME VARIATIONS OF A TRAIT AND CAN LEAD TO THE RAPID EVOLUTION OF A POPULATION C. DISRUPTIVE SELECTION FAVORS BOTH EXTREME VARIATIONS OF A TRAIT, RESULTING EVENTUALLY IN NO INTERMEDIATE FORMS OF THE TRAIT AND LEADING TO THE EVOLUTION OF TWO NEW SPECIES.

17 Speciation What is speciation? OCCURS WHEN MEMBERS OF THE SIMILAR POPULATIONS NO LONGER INTERBREED TO PRODUCE FERTILE OFFSPRING WITHIN THEIR NATURAL ENVIRONMENT. (the formation of a new species)

18 Causes of Speciation a. Geographic Isolation – members of a population are separated by a structural object like a river, ocean, mountain range, pond, lake b. Reproductive (Temporal) Isolation 1. mating seasons 2. mating habits c. Change in the number of chromosomes – polyploidy – DNA is not compatible.

19 Occurrence of Speciation
a. Gradualism – ORGANISMS SLOWLY CHANGE OVER A LONG PERIOD OF TIME b. Punctuated Equilibrium-A MAJOR CASTROPHE HAPPENS AND ORGANISMS CHANGE QUICKLY

20 Patterns of Evolution a. Adaptive Radiation- COMMON ANCESTOR EVOLVED INTO DIFFERENT SPECIES EXAMPLE – ANCESTRAL LASAN FINCH MAUI PARROT BILL CRESTED HONEY CREEPER GROSBEAK FINCH b. Divergent evolution- IS ADAPTIVE RADIATION; ORGANISMS BECOME LESS ALIKE OVER TIME c. Convergent evolution- ORGANISM HAVE DIFFERENT ANCESTORS BUT BECOME MORE ALIKE IN TIME EXAMPLE: WATER LIVING ANCESTOR LAND LIVING ANCESTOR (GILL SLITS) SHARK DOLPHIN (LUNGS) TORPEDO SHAPED BODY LIVE IN WATER

21 Primates Primate – MAMMALS THAT INCLUDE LEMURS, MONKEYS, APES, HUMAN
- Opposable thumb- GRASP- THUMB CAN CROSS THE HAND - Prehensile tail- GRASP – 5TH LIMB - MONKEYS

22 Types of Primates Hominids- WALK UP RIGHT
TWO GROUPS: 1. GORILLAS AND CHIMPANZEES HUMAN Bipedal- ABLE TO WALK ON TWO LEGS


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