Flashcards
BIOLOGY CHAPTER 7- Variation and evolution
Cards in this deck (58)
- 1Human characteristics affected by genetics (5)• Eye colour
• Blood group
• Natural colour of hair
• Shape of earlobe
• Nose shape - 2Human characteristics affected by the environment (5)• Hair colour and length
• Language
• Scars
• Tattoos
• Nail length - 3Human characteristics affected by both genetics and environment (5)• Height
• Skin colour
• Weight
• Sporting achievements
• Intelligence - 43 processes leading to variation○ Mutations
○ Meiosis
○ Sexual reproduction - 5What was Lamarck's theory?That organisms survived by adapting to their environment. He suggested that body parts developed during an organism's life were passed on to the next generation. He also though that one organism simply developed into another, rather than becoming extinct.
- 6Why was Lamarck's theory wrong?Acquired characteristics do not have a genetic basis. In addition, his theory cannot account for all the observations made of life on Earth. For instance, it would predict that all organisms gradually become complex, and simple organisms disappear.
- 7What is natural selection?Process by which 'good' characteristics that can be passed on in genes become more common in a population over many generations ('good' characteristics mean that the organism has an advantage which make sit more likely to survive)
- 8Evidence for Darwin's theory from the Galapagos Islands• 1831 to 1836 Charles Darwin travelled aboard the H.M.S. Beagle
• A short period of this was spent on the Galapagos islands (19 days)
• Darwin realised that animals and plants that lived here must have originated from mainland South America
• Some species on the island were similar to those on the mainland, but not the same. Others were very different
• The giant tortoises were all different from island to island- Darwin also noted 3 species of mockingbird- each on a different island
• He realised that species were not fixed- they can change
• Darwin recorded his observations and collected specimens of animals and plants from the islands - 9How did Darwin come up with the theory of 'natural selection'?He knew that organisms produced more offspring than necessary to maintain their numbers. However the populations were reasonably stable, meaning the death rate was high. This was a 'struggle for existence', as Darwin called it. Due to variation in species, some individuals survived better than others. This was natural selection.
- 10How are fossils formed?
- 11What parts of an animal or plant are usually fossilised?The hard parts of an animal (bones, shell or teeth) and the hard woody parts of a plant
- 124 conditions present for fossil formation• Exclusion of oxygen
• Rapid burial - before the hard parts are either eaten or dissolved
• Needs to be deeply buried and turned to rock
• fairly calm, unchanging thermal and mechanical conditions - 13Where have whole fossilised organisms been found?• In amber, a hardened form of tree sap
- 14What is radiometric dating?a method of dating geological specimens by determining the relative proportions of particular radioactive isotopes present in a sample.
- 15How are the relative ages of fossil species worked out?As layer upon layer of rock is added, each must be younger than the one beneath. From this we can tell the relative ages of the fossils in these layers
- 16Why is the fossil record incomplete?Because fossil formation is actually a rare occurrence. Conditions must be just right and geological activity over many years may have destroyed most fossils. The older a fossil is, the more likely it is to have been lost.
- 17Why do we have so few fossils of early life forms?Because many of these were microorganisms or were soft-bodied so fewer traces of them exist. Although sometimes, condition can enable soft-bodied animals t be found.
- 18Which early organisms have left traces?Archaea and Bacteria have left traces of the unique chemicals that they have produced
- 19Give an example of a type of organism that has changed very little in billions of years and how we know this.Certain bacteria- we know this because if the unique chemicals in their cell membranes that fossil bacteria left traces of
- 20Who were the co-author of the theory of evolution?Darwin and Wallace
- 212 examples of animals that show warning colourationWasps and cinnabar moth caterpillar
- 22What is a species?Organisms that can interbreed to produce fertile offspring
- 23What caused the dark form of the moth to be produced in Britain?Britain became heavily polluted during the Industrial Revolution and soot covered the trees, killing lichens and blackening the bark. dark moths were well camouflaged on tree trunks and less likely to be eaten by birds so they had an advantage over the pale form.
- 24Who proposed this explanation?James W. Tutt
- 25Which amateur lepidopterist tested Tutt's hypothesis?Bernard Kettlewell
- 26What experiments did he carry out?His first experiment was in a heavily industrialised woodland near Birmingham, with around 90% melanic (dark) moths. He released a large no. of peppered moths, marking the underside of the wings with a spot of paint. He then caught 770 peppered moths. Recaptured moths from the first part of the experiment were identified by the spot of paint.Others were wild. Overall, more melanic moths were recaptured. When he repeated the experimented in an unpolluted area, he recaptured more pale moths.
- 27What conclusion could Kettlewell come to from his experiments?When he released the moths in a polluted area, more black moths, returned than white moths, meaning that the dark moths were better adapted to the surroundings that the white moths. However in unpolluted area,more pale moths were recaptured, meaning the pale moths were better adapted to the unpolluted areas. The distribution of peppered moths was correlated with the level of pollution.
- 28Why did air quality improve in the UK in the 1950s and 1960s?Due to anti-pollution measures
- 29How were human characteristics thought to be inherited in the nineteenth century?Most people believed that God had created us the way we were
- 30How does antibiotic resistance develop?There is a population of bacteria and a mutation occurs so that one or more bacteria in the population are resistance to the antibiotic. The antibiotic is taken, however the course is not completed, therefore all but the resistant bacteria die. The resistant bacteria reproduce via binary fission, to produce a whole population of bacteria that are now resistance to the antibiotic.
- 31How do we currently treat bacteria that are resistant to common antibiotics?Certain antibiotics, which are kept in reserve as 'last-resorts' are used
- 32What must patients not do to slow down antimicrobial resistance?Never share antibiotics, skip doses, or save some for later, or leave incomplete courses
- 33What is the problem with developing new antibiotics?Economic- testing, development and trialling of new antibiotics is slow and costly; and new antibiotics are more likely to be used as a last resort; pharmaceutical companies won't sell much of their new antibiotics and will lose money
Scientific- As new resistant strains emerge, an antibiotic may not be effective for long - 34Describe the process of selective breeding.The animal breeder selects the animals from the flock with the most of the desired characteristic. Offspring are produced from the selected animals. Some of the offspring now have that desired characteristic. These will be selected and bred to produce offspring. An increased number of the population will have the desired characteristic. The breeding programme until all of the animals have the desired characteristic.
- 35What is a dog's pedigree?A record of the animal's percentage, to show how true it is to its breed
- 36Problems of inbreeding• Birth defects
• Genetically inherited health problems
• Makes animals prone to disease
• Rare disease alleles could increase in inbred animals
• Limited gene pool/ range of genes in the population - 373 characteristics that crop plants could be bred for• To grow and mature quickly
• To have a distinctive taste, aroma or colour, for example, in strawberries
• To have long shelf-life, store well or can be frozen - 38What is genetic engineering?Also called genetic modification or genetic manipulation, is the direct manipulation of an organism's genes using biotechnology- involves taking specific genes from organism and introducing them into the genome of another
- 39What 2 organisms can be genetically engineered to produce insulin?• The bacterium, Escherichia coli
• Yeast - 40How is insulin produced using E. coli?
- 41How are viruses used to transfer genes made safe?By inactivating genes related to infection
- 42How are antibiotic-resistant genes modified?When orgnaism or cells aremodified, not all cells take up the foreign gene. The cells that ahve not need to be screened out. When the cells are modified, a genetic marker gene is inserted into the organism's genome as well as the required gene. This marker gene is usually one giving antibiotic resistance. When the culture of cells is treated with antibiotic, any cells that have not take up the required gene successfully will be killed. Resistance is created to the antibiotic kanamycin, which is rarely used today.
- 43Why is a genetic marker used when genetically modifying organisms?Helps scientists identify when a plant cell has been successfully genetically modified
- 44Describe the process of gene therapy.
- 45Limitations of gene therapy○ How to deliver the replacement gene effectively
○ Any successful gene therapy would not prevent the person from passing on an inherited condition to their children. It's the patient's body cells being modified. Any modification of reproductive cells,or germline gene therapy, would be both technically and ethically difficult- not permitted by law - 46What is the process of adult cell cloning?
- 47What are embryo transplants?A developing embryo is removed from a pregnant female early in the pregnancy, so the cells have not yet become specialised. The cells are separated, grown for a while in culture and then transplanted into host mothers.
- 48What is the purpose of embryo transplants?Cloning- enables the animal breeder ti produce many animals that have identical characteristics. Can be important commercially, perhaps to produce high milk volumes or quality beef.
- 49What is one method used to genetically modify and then clone plants?
- 50What is tissue culture?The process or technique of making body tissue grow in a culture medium outside the organism
- 51What is another way, apart from tissue culture to produce new, identical plants?Gardeners produce many plants using cuttings. A leaf and stem are cut and dipped in hormone powder to encourage rooting. The cutting then grows into a new plant.
- 52What is the order of classification of organism?KINGDOM (Animalia)
PHYLUM (Chordata)
CLASS (Mammalia)
ORDER (Primates)
FAMILY (Hominidae)
GENUS (Homo)
SPECIES (sapiens) - 53What is the binomial system?Formal system of naming species of living things by giving each a name composed of two parts- a generic and species name (Homo sapiens)
- 54What is an evolutionary tree?A branched diagram that shows how scientists think organisms evolved as they diverged from common ancestors
- 55At least how many mass extinctions do fossil records show over geological time?Five
- 56Why can we only estimate the number of extinct species?Because the fossil record is incomplete, so we don't know all the organisms that have been alive
- 577 causes of extinction• Introduction of new species
• Transformation of landscape
• Pollution
• Poaching and Hunting
• Deforestation
• Human over-population
• Climate change - 58Why could introducing a new species, lead to extinction? (3)• Could be new predators
• Could compete with native organisms for food
•Could introduce new diseases
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- Year 10 Biology Flashcards on BIOLOGY CHAPTER 7- Variation and evolution, created by UnknownSnowFlake 123 on 21/03/2018.
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