UNIT IV EVOLUTION CHANGE AND DIVERSITY Why is

UNIT IV: EVOLUTION, CHANGE AND DIVERSITY

Why is the topic of evolution so controversial? https: //answersingenesis. org/theory-of-evolution/in-schools/ https: //www. youtube. com/watch? v=Ud. XHkt. AAOcc

Modern Day Evolution Industrial Melanism- The Peppered Moth • An example of evolution • It highlights the importance of variation within a species and how this adaptation can help them survive. Peppered Moth Stimulation http: //www. techapps. net/interactives/pepper. Moths. swf

Page 2 in Booklet Before During After - Light moths were more common - Light and dark - Dark moths equal in became more number common - Trees were light, so dark moths got eaten - Trees were light & dark - Most trees were dark from pollution, so light moths got eaten

Adaptation- an inheritable characteristic that helps an organism survive and reproduce in an environment.

Variation- the differences in characteristics of a species.

Natural Selection Artificial Selection • A process where individuals with favorable traits survive to pass on their traits to their offspring • A process where a breeder decides what traits will be passed on • Ex: Peppered Moth • Ex: Dog breeding

Contributions of Scientists Page 3 in Booklet Georges Cuvier • Developed the science of paleontology (fossils) • He believed catastrophism caused new species

Thomas Malthus • He proposed theory of population growth • There is not enough food to feed the growing world population

Charles Lyell • Evolution is slow and gradual • He believed in Uniformitarianism

Jean Baptiste Lamarck 1. Law of use or disuse 2. The Law of Inheritance of Acquired Characteristics

1. The Law of Use or Disuse • Use it or lose it If an organism uses a trait it remains active and strong, but if not used then it becomes weak and disappears.

2. The Law of Inheritance of Acquired Characteristics • Favorable traits can be passed on to the next generation. • Since giraffes stretched their necks during their lifetime then this trait was passed onto their offspring.

Modern Day example that disproves theory of "inheritance of acquired characteristics": Chinese women bound the feet of their infant children for several thousand years, yet the feet of Chinese women today are normal in size.

Alfred Russell Wallace • Forced Darwin to publish his book, he was working on a similar theory

Charles Darwin Developed theory of Natural Selection (survival of the fittest) Don’t write: His came up with his theory after consulting several different sources: A. Maltus’ Essay B. Selective (Artificial) Breeding C. Lyell’s Book D. Darwin’s Personal Observations https: //www. youtube. com/ watch? v=6 GNUl. Zh. E_j. E

Page 4 booklet Explain how the finches evolved on the Galapagos Island. 1 st – variation within the species (ex: beak shape) 2 nd – those with the “best” adaptations were more fit (ex: large beak to crush seeds) 3 rd – they survived in the environment 4 th - passed on their traits to offspring

Page 4 booklet Why is the medical community concerned about the overuse of antibiotics? • People often don’t take all their antibiotics • As a result, all the bacteria are not killed • The strongest bacteria is left to reproduce and pass on their traits to the offspring, making extra strong bacteria that are resistant to antibiotics

Finish pages 4 and 5 in Booklet for homework These are practice questions

Support for the modern theory of evolution • Scientific evidence we use to support theory of evolution

1. Biogeography • The study of the geographic distribution of a species. Video: Island of Lemurs https: //www. youtube. com/watch? v=Q_7 c. Vy. M 8 Efg&safe=active

2. Comparative Anatomy a. Homologous structures –Anatomy is similar in shape, structure and origin.

b. Analogous structures • similar structures but are anatomically different. This is evidence to suggest theses organisms did not evolve from a common ancestor.

c. Vestigial organs - structures that have lost their function, but were functional in an ancestor of the organism.

Video: Evolution of Whales http: //ocean. si. edu/oceanvideos/evolution-whalesanimation

3. Comparative Embryology • Compare the structures of the embryos Similar structure is evidence for close evolutionary relationship

4. Comparative Biochemistry/ Molecular Biology • Scientists compare the chemical composition (DNA) of different organisms. Examples: Hemoglobin of monkey’s is similar to the hemoglobin of man. The insulin from a pig or cow can be used to treat diabetes in humans.

5. DNA sequencing • Compare the sequence (order) of DNA Example: • Humans and chimpanzees have 2. 5% difference in their DNA sequence • Humans and lemurs have 42% difference • Therefore humans are more like chimpanzees than lemurs

6. Fossil Record Relative Dating - an estimate of the age of a fossil by its location in sedimentary layers (oldest on bottom) a. Scientists have discovered that it takes approximately 1000 years of sediment to produce 30 cm of sedimentary rock. • Example: 150 cm deep means a relative age of 5000 years.

b. Absolute Dating - an exact age of a fossil done by radioactive dating Living organisms accumulate certain radioactive isotopes when they are living. Once these organisms die, the radioactive isotopes start to breakdown. The rate of this breakdown is called half life. The greater the amount of decay product the older the fossil.

How to do a half life problem # of Half Lives Fraction Percent Age 1 ½ 50% 5730 2 ½ x ½ 25% 5730 + 5730 = 11460 3 ½ + ½ 12. 5 % 5730 + 5730 = 17190 4 ½ + ½ + ½ 6. 25% 5730 + 5730 = 22920 5 ½ + ½ + ½ 3. 125% 5730 + 5730 = 28650

Half-Life Problems (page 8 in notes) • Carbon 14 has a half life of 5730 years. How long will it take for carbon 14 to decay to 1/8 of its original amount?

Examples include some of the isotope pairs found in the following table: Isotope Pair Half-Life in Years Useful Range in Years Carbon 14/Carbon 12 5730 60 x 103 Uranium 235/Lead 207 700 x 106 Over 500 x 103 Potassium 40/Argon 40 1. 25 x 109 Over 500 x 103 Uranium 238/Lead 206 4. 5 x 109 Over 100 x 106

Half Life Problems Page 7 in Booklet 1. Carbon 14 has a half life of 5730 years. How long will it take for C 14 to decay to 1/16 of its original amount?

2. Uranium has a half life of 700 x 106 years. How long will it take for uranium to decay to ¼ of its original amount?

3. The half-life of carbon-14 is 5730 years. How old is a fossil that contains 6. 25 % of the original carbon-14?

4. If the half-life of carbon is 5730 years, what percent of carbon would be contained in a rock sample that is 22 920 years old?

Finish pages 8 and 9 in Booklet for homework These are practice questions

Hardy-Weinburg Equilibrium Page 10 in Booklet • Used to determine whether or not evolution is occurring in a population. • The law states that under certain conditions, allele frequencies will remain constant (genetic equilibrium) in a gene pool and there will be no evolution. http: //www. youtube. com/watch? v=Jsu. Jlew a. PX 0&safe=active

Five Conditions 1. The population must be large. (No genetic drift) 2. Individuals must not migrate into or out of the population 3. Mutations must not occur 4. Reproduction must be completely at random. 5. No genotype is more likely to survive and have offspring than any other genotype.

Allele frequency p+q=1 p is the dominant allele frequency q is the recessive allele frequency

Genotype frequency p 2 + 2 pq + q 2 = 1 p 2 homozygous dominant frequency (TT) 2 pq heterozygous dominant frequency (Tt) q 2 homozygous dominant frequency (tt)

Practice Public Exam Question 1. A teacher observed that the frequency of students able to roll their tongue has decreased over thirty years. Is this population in Hardy. Weinberg Equilibrium? Give three reasons to support your answer.

Answer:

How can you tell evolution is occurring? If the allele frequency in a population changes, then the Hardy-Weinberg Law fails and it is therefore a sign that evolution is occurring.

Page 11 in Booklet 2 (a) in 30 pea plants, they have 60 alleles present for height (each plant has 2 alleles). A survey tells you that the frequency of the T allele 0. 6 (60%) and the frequency of the t allele is 0. 4 (40%). You can use the Hardy-Weinberg formula to calculate the genotypic frequencies of the population.

(b) Let’s assume that for the next few years, some pollen from another nearby garden of plants fertilizes some of the pea plants in your garden (in migration and random mating have occurred). Years later, you survey your plants for height and find that the T allele frequency is now 0. 73 (73%). What does this prove? Explain.

3. A biologist has found that 10 percent of a population of bats are hairless, which is a recessive trait. Assuming that the population is Hardy-Weinberg Equilibrium, determine the genetic structure (genotype and allele frequencies) of a population?

Mechanisms for Variation • There are FIVE mechanisms that can affect the biodiversity of a population. 1. 2. 3. 4. 5. Small population (Genetic Drift) Non-random mating Mutations Gene Flow Natural Selection

5 finger evolution • http: //www. youtube. com/watch? v=5 Nd. Mnlt 2 ke. E&safe=active

2. Genetic Drift • In large populations, genes expressed will be similar to the parent generation (mutations are noticeable in large populations) • BUT, in very small populations, the frequencies of particular alleles can be affected drastically by chance alone This is called genetic drift.

There are 2 types of genetic drift: A. The Bottleneck Effect • When a population is greatly reduced because of things like natural disasters (earthquake, fire, flood), overhunting, and habitat destruction • The gene pool is therefore much smaller leaving fewer variations in the population.

B. The Founder Effect • When a small number of individuals colonize a new area, they will probably not possess all the genes represented in the parent population. • Since this new population has moved to a new environment, there would have different environmental selective pressures affecting them than the parent population would have.

Ex: Type O blood is recessive, yet the most common blood type in NL

2. Non-Random Mating • Any situation where individuals do not choose mates randomly from the whole population. • Ex: Inbreeding, or choosing mates because of proximity, or choosing mates for similarity of phenotype (ex. Dogs) • Leads to a decrease in genetic diversity.

3. Mutations • If a mutation occurs in a germ cell (sex cell) it alters the DNA of the gamete and can be passed on to future generations. • A mutation is unlikely to cause evolution in the population unless it provides a selective advantage (makes it easier for the organism to live in their environment). • Unfavorable mutations may provide a selective advantage when the environment changes (ex: Antibiotic resistant bacteria)

4. Gene Flow • The movement of new alleles into a gene pool and the movement of genes out of a gene pool. • Ex: A windstorm or tornado can bring new seeds or pollen or even birds into a population.

5. Natural Selection • Survival of the fittest • These members survive to pass on their genes to the next generation. • Four types of natural selection (turn to page 13 in Booklet)

A. Stabilizing Selection • • • Favors the intermediate phenotype Result: Population stays the same Ex: Medium colored moths due better than light or dark moths

B. Directional selection • Favors phenotypes at one extreme • Result: population shifts in the direction of that extreme. • Ex: the environment became polluted so dark moths did better

C. Disruptive (diversifying) selection • Favors both extremes of the phenotype • Result: two new populations result • Ex: Light moths and dark moths do well, medium colored die off

D. Sexual Selection • • One sex of a species uses adaptations to compete for a mate Ex: Male peacocks have brightly colored feathers

Finish pages 14 and 15 in Booklet for homework These are practice questions

What is Speciation? The image above shows two orchid fish. Each is a different species from the other that came from the same common ancestor. How is this possible?

• They are adapting to the environment in which they live and as a result are becoming different species

Turn to Page 16 in Booklet • Species – a group of organisms that can reproduce and make fertile offspring • Adaptive Radiation – a change in the environment causes a species to adapt and change into a new species. Two types: 1. Allopatric Speciation 2. Sympatric Speciation

• Allopatric Speciation – members of a species become separated from each other (ex: river) and become different species • Sympatric Speciation – a new species forms among an already existing species

What is a Hybrid? • The offspring that forms when two separate biological species breed • the hybrid offspring are infertile or not viable Ex: horses and donkeys can mate and produce offspring called a mule which is infertile.

Types of Biological Barriers Page 17 in Booklet • Pre-zygotic – means two species cannot make a zygote • Post-zygotic – means a zygote gets made, but there is an issue with the hybrid (baby)

Pre-zygotic barriers 1. Behavioral isolation –behaviors do not match so they are not interested in mating

2. Temporal isolation – Timing is off Ex: mate at different times in the year

3. Habitat isolation –live in different habitats

4. Mechanical isolation – anatomically incompatible (their parts don’t fit!)

E. Gametic isolation – gametes are unable to fuse to produce offspring.

What type of Pre-Zygotic Barriers are shown in each picture?

Video: The Speciation Song http: //www. youtube. com/watch? v=WDPs. ZPKSE Fg&feature=kp&safe=active Video: Speciation http: //www. youtube. com/watch? v=PKb 8 Yi 5 xzh E&safe=active

Post –Zygotic barriers 1. Hybrid in viability –Mitosis is prevented from happening normally because of incompatible genes.

2. Hybrid sterility – two species mate and produce sterile offspring like the mule.

3. Hybrid breakdown –hybrids may be weak and die

Finish page 18 in Booklet for homework This is a practice question

Types of Evolution Page 19 in Booklet 1. Convergent 2. Divergent 3. Co-evolution

Convergent Evolution • When unrelated species have similar adaptations due to occupying a similar niche • They evolve to share a habitat Ex: wings are all used for flight, bats fly at night

Divergent Evolution • Species that were once similar become two new species

Co- Evolution • When two species evolve gradually together, each one responding to the changes in the other.

Pace of Evolution • At present, scientists do not agree on the rate at which evolution occurred. Two opposing viewpoints are: A. Gradualism B. Punctuated Equilibrium

A. Gradualism • new species arise gradually because of small variations. • In other words, evolution occurs slowly and continuously over long periods of time. Based on Darwin’s theory

B. Punctuated equilibrium • A species is unchanged for extended periods of time and then in a relatively short period of time, rapid change occurs. • Was proposed by Steven Gould and Niles Eldridge.

The Origin of Life 1. 2. 3. 4. 5. 6. Chemical Evolution (Big Bang Theory) Heterotroph Hypothesis Symbiogenesis Panspermia Theory GAIA Theory Intelligent Design Theory

Haldane- Oparin Theory (BIG BANG THEORY) • Early atmosphere was very hot and consisted of: • • hydrogen (H 2) water vapor (H 2 O) ammonia (NH ) methane (CH 4) 3 • Oceans were “hot, thin soup” which was perfect for chemical reactions to occur • Energy was available to start the chemical reaction – BIG BANG (UV light, lightening and/or volcanic heat) http: //www. youtube. com/watch? v=lh. TSf. OZUNLo&feature=kp&safe=active https: //www. youtube. com/watch? v=28 CBRu_k. Mb. Y

Miller and Urey Experiment (1953) • Proved Oparin and Haldane Theory, that life could come from non-living things Details of the experiment: They took methane, ammonia, water and hydrogen and placed them in a flask. They exposed the flask to sparks to represent the sunlight and lightening on the earth at that time They discovered that it was possible to create organic compounds (amino acids) that could have been the beginning of life on earth.

2. Heterotroph Hypothesis • the proposal that the first living organism was a HETEROTROPH

3. Symbiogenesis • an evolutionary theory that explains that eukaryotic cells developed from prokaryotes. • Organelles inside the cell worked together (symbiotic relationship) to make a more complex cell

4. Panspermia Theory This theory suggests that life came from some other source outside of the earth http: //channel. nationalgeographic. com/channel/videos/theories -about-lifes-beginnings/

5. Gaia Hypothesis • It suggests that the earth, including all of its abiotic and biotic components may constitute a huge, living, self-regulating system.

6. Intelligent Design Theory • GOD created earth and all living things

Overview of Evolution • http: //www. youtube. com/watch? v=d 4 VS 00 it 40 o