EVOLUTION-Copy.of presentation on evolution.pptx

Evolution ppt

1. EVOLUTION is defined as a process involving transformations in living things occurring over a long period of time. The duration of time involved in this process is in thousands of years.

2. A. THEORIES OF EVOLUTION

3. This theory can be summarized into: 1. Organisms desire to improve themselves and become more advance. 2. The effort to improve causes same body structures to be constantly used, others are not used. The frequently used body structures develop, while unused structures weaken and eventually disappear. This is known as the principle of use and disuse. 3. Modifications of structures due to use or disuse are inherited by the offspring. This is called the principle of inheritance of acquired characteristics. An example is the giraffe’s neck becoming longer in order to get food .

4. 2. The Darwin-Wallace Theory It was two English men, Charles Darwin and Alfred Wallace. Independently proposed their theory of biological evolution. Of the two, Darwin is more popularly known. Although there were other naturalists who have proposed their theories of evolution, it is the Darwin-Wallace version which is the most widely accepted today.

5. 1.Natural Selection

6. Through natural selection, organisms attain to retain those features which allow them to have an advantage in adjusting the changing conditions of their environment. If a certain species does not have those characteristics which allows it to survive and leave offspring behind, then that species could become extinct.

7. Briefly his explanation goes: 1. The number of offspring is usually greater than the available resources necessary for survival. 2. Every organism must struggle to survive. 3. Some variations allow members to survive and reproduce better than others. 4. Organisms that survive and reproduce pass their traits to their offsprings and helpful traits gradually appear in more and more. These variations enable them to “fit” into their environment and those who lack these are eliminated.

8. 2. Artificial Selection

9. Plant and animal breeders manipulate crosses between different varieties of organisms to produce offspring with particular traits. Thus, we have fruits and vegetables, and orchids or ornamental plants occurring in different sizes, shape andcolor . Likewise, there are also varieties of domestic cattle, swine, poultry, and fish. These numerous varieties are produced in a relatively short period of time, since man can easily regulate the crosses or mating which could immediately produce the desired traits in the offspring

10. B. EVIDENCE OF EVOLUTION The principal concept of biological evolution is that the different organisms existing today all descended from a common ancestor. The descent of these organisms involve modifications of the original pattern of the common ancestors. This modification came about because nature selected them for over long period of time.

11. 1. Fossils - are remains of evidence of a living thing. The most common fossils are bones, skulls and seeds of pollen grains. Most fossils are formed when the whole or part of an organisms becomes buried in sedimentary rocks, which provides the most important evidence about the evolution of plant and animals. Petrified fossils are formed through petrification. Imprints are formed when soft body structures such as feathers and leaves leave impressions in soft sediments such as mud. Molds and casts are formed with the same shape as the original organisms. Scientists determine the absolute age of rocks and fossils by using radioactive dating techniques

12. 2. Embryological evidence The growth and development of an embryo is controlled by its genes. Similarities in the early stages of embryo development are further evidence that living things have evolved from early living things and they share common ancestry.

13. 3. Homologous Structure The age of fossils is used to determine by taking note of the characteristics of the layers of the sedimentary rocks in which the fossils are found. Similarities in the shape and arrangement of bones show they evolved from the same ancestors. Analogous structures also determine through anatomy

14. 4. Chemical Evidence DNA and protein sequence are the chemical evidence, which shows that two or more organisms are closely related when they have similar sequence of DNA molecules. The same is true with the specific structure of protein. Variation of protein structure of one group as it evolves into another group show relationship in organisms.

15. 5. Vestigial Structure A vestigial structure is a body part that is reduced in size and does not seem to have a function. Example is the tiny leg bones of snakes which suggest that they evolved from an ancestor that had legs.

16. ACTIVITY TIME!

17. Directions: Circle the letter of the correct choice. . 1. ___________developed the theory of evolution by natural selection. a. Alfred Russel Wallace b. Charles Darwin c. Jean Baptiste Lamarck d. Charles Lyell 2. Natural Selection states that a. a change in a species occurs over time. b. nature selects the variation within a species that are most useful for survival. c. fitness is an organisms ability to survive and produce fertile offspring. d. all of the above

18. 3. Evidence of evolution includes a. DNA sequence analysis b. fossil records c. anatomical evidence d. all of the above 4. Examples of analogous structures a. the tails of mice and rats b. the limbs of human and apes. c. the wings of bats and birds d. all of the above 5. The strongest evidence for evolution from common ancestor is a. similar DNA sequence b. similar body structure c. similar embryological structure d. similar fossils

19. Activity 1: Evolution: Fact, Fiction or Opinion Directions: Read the following statements about evolution. Identify whether the statement is fact, Fiction or opinion. Write your answer on the space provided before each number. ____________1. There are no transitional fossils. ____________2. Humans are more evolved than reptiles. ____________3. The theory of evolution has changed since the time of DARWIN. ____________4. Humans evolved from monkeys. ____________5. Charles Darwin developed the theory of evolution. ____________6. Evolution should be taught in biology class only. ____________7. Humans share a common ancestors with chimpanzees. ____________8. Evolution ensures that all organisms are perfectly adapted. ____________9. All traits are adaptations produced by natural selection. ____________10. Evolution can be observed

20. Activity 2: Match Me Directions: Analyze the words given below. Supply the complete answer to make the analogy correct. (2 Points Each) 1. Lamarck: Acquired trait; Darwin: _____________ 2. Fossils: Rocks; _____________: Tail bone 3. Analogous Structure: Anatomy; ______________: Radioactive Dating 4. Fossils: remains; Chemical Evidence: _________

21. ANSWERS 1. B 3. D 5 . A 2. D 4. C

22. ANSWERS Activity 2: Evolution: Fact, Fiction or Opinion 1. Fact 6. Opinion 2. Fiction 7. Fact 3. Fact 8. Fiction 4. Fiction 9. Fiction 5. TRUE 10. Fact

23. ANSWERS Activity 2: Match Me ( 2 POINTS EACH) 1. Natural Selection 3. Rocks/ Fossils 2. Vestigial Structure 4. DNA