Life Science Notes 5 PDF

Resistance Natural selection : Antibacterial cause diseases such as tuberculosis and preumonia...

Resistance Natural selection : Antibacterial cause diseases such as tuberculosis and preumonia in humans. People who Some bacteria bacterial infections often given antibiotics to kill the bacteria. However, some are suffering from are resistant to antibiotics. This means they are not killed by the antibiotics. Darwin's theory of bacteria are the evolution of bacteria that are resistant to an antibiotic evolution can explain. Darwin's 1 Theory says is variation in the individuals of a species · there · some individuals will die before reproducing o the individuals that survive will be the ones with the best survival characteristics 0 When these individuals breed, they will produce more individuals with the good survival characteristics. 2 bacteria that cause a disease have slight variation that make them different to each other · All the antibiotic medicine, not all of the bacteria be killed it. · When you take an may by Any bacteria that survive will be the ones resistant to the antibiotic · If you take all of the antibiotic that the doctor prescribes , all the bacteria will be killed by the medicine or by your body's immune system · If you stop taking the antibiotic early , there may still be many bacteria left in your body. These bacteria can all become to the antibiotic These bacteria could be passed on to another person resistant. · If another person is infected with these bacteria , the antibiotic medicine will not work because all the bacteria in their. body are resistant to it of selection Types Natural selection advantageous adaptations selected - organisms with are by nature and pass - They are more likely to survive , reproduce , on their genes Artificial selection - organisms with desirable phenotypes are selected by man- - They are more likely to survive reproduce, and pass on their genes  selection) SexualSelection /a specific type of natural with sexy characteristics selected - Organisms are - They are more likely to (survive) , reproduce , and pass on their genes - sexy characteristics are exaggerated traits Cornaments) or behaviours that are the result of sexual selection do the long gestational period therefore because females and - Females usually choosing usually have a , cannot mate again for a while whereas makes can mate again right after Sexual Dimorphism Male- -Female - Females usually don't have exaggerated traits as they tend to be costly (decrease fitness) and provide no benefit to the female - Females are attracked to these characteristics because they are costly· Having an exaggerated characteristic is usually a good indicator of strength or good health : ultimately - good genes mating with these individuals likely to have increase fitness result from the are an - Offspring that The Lion's Mare · Females are attracted to males with larger , darker makes o correlation with higher testosterone levels o better nutrition and health Natural Selection · More muscle and aggression o better sperm count/Ertility life · longer · But imposes a cost to the male Is It worth it ? · Hot ! Genetic Drift Other Forces of Golutionary change Selection (natural/artifical/sexual) Genetic Drift survival will in ↳> traits that improve or reproduction accumulate 1> frequency of traits can change a population events in the population due to chance · adaptive change o random change o small populations are more susceptible Bottleneck Affect few members to survive , but not necessarily the ones with An event causes only a fitness change in allele frequencies the highest > - oeg forest fire Founder Affect of individuals become isolated and start a new population they may have A small group - different allele frequencies to the original population South unusually high frequency of the eg. Afrikaner population in Africa - give Huntington's disease that causes Gene Flow - When a member of a different population immigrates and joins another population introduce new alleles into the population - They may non-native species transported humans eg. by Evidence For Evolution A. The Fossil Record the remains or evidence of past life recorded in rock (molds impressions, bones , shells, teeth, preserved in ice. etc Fossil : , , be determind fossils position the layers. The oldest fossils found below. 2 Relative dating - age can by the in are surface fossils nearer the Isetopes atoms wh the a re younger are. Absolute dating 2 - uses the principle of radioactive dating same number of and protons ↳ The half-life of known radioactive compounds never changes different numbers of neutrons. Over ↳ Example of absolute dating time Istopes decay and change o Potassium -40 decays to Argon - 40 Potassium -40 deays to half its original amount in 1 3 billion years. o o I there are equal amounts Potassium - 40 and Argon-40 in a rock sample, how old is the rock sample ? Answer: 1 3 billion years. - gradual evolution of the modern horse. Ex. Fossil remains clearly show the