S5 Biology Revision Notes 2024 PDF

S5 Biology Revision Notes 2024 (Version_18th_Nov, 2024) 1- History of the Earth / Geological History Suggestions, Examples, Prompts and Ideas as you Revise Essential characteristics of the 4 Eons Hadean (Greek word for ‘Underworld); Archean (Primitive), Proterozoic (first...

S5 Biology Revision Notes 2024 (Version_18th_Nov, 2024) 1- History of the Earth / Geological History Suggestions, Examples, Prompts and Ideas as you Revise Essential characteristics of the 4 Eons Hadean (Greek word for ‘Underworld); Archean (Primitive), Proterozoic (first life); Phanerozoic (visible life) (Hadean, Archean, Proterozoic, Phanerozoic) What is the Age of the Earth? Do you know the (i) Chronological Order (ii) Duration or Length of time (iii) Correct Spelling, for all the Eons? Essential characteristics of the 3 Eras: Meaning for each Era? What are the major events from each Era? (Palaeozoic, Mesozoic, Cenozoic) Quote - The Jurassic Period was in the middle of the Mesozoic Era which consists of 3 Periods (Triassic, Jurassic and Cretaceous). Blah Blah... Major events Palaeozoic (Ancient , Past or Mesozoic (Middle Life or Dinosaurs Cenozoic (Recent, Present or Modern Old Life aka Age of Life). Age aka Age of the Reptiles). Life aka Mammalian Age). Duration of era 541-252 mya 251.9 to 66.0 mya 66 mya to today How many periods 6 3 3 Age of what? Invetrebates (e.g Reptiles, Dinosaurs, First –(birds, Larger Mammals, Birds, Conifers, and Dominance of what? Arthropods), Amphibians, flowering plants and insects that Flowering Plants Evolution of what? Who Fishes and the 1st Life on pollinated them, small mammals) Human evolution were the winners? Land Who lost out or got Many Trilobites, Many Dinosaurs Many plants and animals. e.g. dodo, extinct by the end of Many other marine animals woolly mammoth. era? Who were the You can find many more on the IUCN losers? Red List. Geographical Creation of the Pangaea began separating into the Northen part of Laurasia separated into occurrences or Supercontinent Pangaea modern continents. (Laurasia + Greenland and Scandinavia. phenomena that Gondwanaland). occurred Mass extinctions World’s largest mass Massive meteorite impact in Mexico The 6th mass extinction is the Holocene (6 mass extinctions to extinction. The Permian wiping out the dinosaurs and up to Extinction. It is an Ongoing extinction date) Extinction (240 mya) 80% of life on Earth. that is primarily caused by humans. The 3rd extinction - The Great The 5th mass extinction- Cretaceous- Dying Paleogene OR C-P OR K-T Extinction Explaining the link between mass extinction and the Think of ‘Losers’ and ‘Winners’ with reference to Extinction? Losers died out and Winners dominated or flourished in the absence of the Losers emergence of new species Some examples- (i) Dinosaurs died out and Large Mammals dominated and flourished in the absence of the dinosaurs. Getting rid of the bullies allows the weaker ones to flourish. 2- Evidence for Evolution Suggestions, Examples and Prompts A. Fossils as evidence of evolution: Distinguish between ‘Remain (Body)’ (actual organism) and ‘Trace’ (action or activity of the organism) fossils. Types of Fossils: Remains (Body) Fossils has many subtypes. Remains (Body) Fossils AND Trace Fossils (i) Organism’s soft part decays, bone is preserved by turning into bone fossil (e.g. bone turns to rock→ bone or rock fossil). Remains = (e.g. imprint, inclusions, fossilisation) (ii) Organism’s soft part decays but leaves an imprint which turns into rock (e.g. moulds or casts) Trace = (e.g. footprints, poo, burrows) (iii) Organism’s entire body is preserved (e.g. inclusion fossils such as amber fossils, ice fossils, tar fossils etc).  S5 Biology Revision Notes 2024 (Version_18th_Nov, 2024) How are fossils formed? (remains) Fossilization is also known as Petrification Fossilization of Bone = Death → Rapid burial → Decay of soft parts → Build-up of sediments (lithification) with replacement of minerals within the bones (mineralisation) → Uplift of land → Exposure Fossilization of Insect = insect trapped in tree sap or amber (inclusion = amber fossil) Fossilization of Ice Mammoth = mammoth frozen/trapped in ice (ice fossil) Fossilization of Animals = animals trapped in pit of tar (tar fossil) How are fossils formed? (trace) Trace Fossils can also be a mould (cup/mug) or cast (cake/jelly) but there is no physical remains of the body (e.g. footprint, poo or coprolites, teeth marking, borrows etc) Define Index fossils (e.g., ammonites, trilobites) What are the characteristics of an Index Fossil? What type of useful information do they provide? B. Relative and Absolute age determination of fossils as Compare (similarities) and Contrast (differences) of Absolute and Relative dating of fossils. evidence of evolution: Explaining relative age determination What is Biostratigraphy? = old fossils at the bottom (), younger fossils are found at the top (). (biostratigraphy) What is Radiocarbon Dating? = using the half-life of radioactive 14C to determine age of fossils Explain absolute age determination (radiocarbon method) C. Transitional Fossils OR Living Fossils as evidence of What are Transitional Fossils? shows links between groups of organisms, evidence of Darwin's theory of evolution. evolution: What does ‘Missing Link’ mean? Archaeopteryx has long been considered a "missing link" between birds and dinosaurs. Explain the importance of transitional fossil using What does ‘Living fossil’? a living species that was thought to have gone extinct from fossil records but hasn’t changed over millions of years examples (e.g., Archaeopteryx, Coelacanth, Platypus). e.g., Coelacanths. Complete Biology IGCSE 3rd edition Chapter 1.5, pg. How do following show that are Transitional Fossils, Missing Link or Living Fossils? *12-13 Archaeopteryx = are considered transitional fossils between dinosaurs and modern birds because it blends avian and reptilian features, it was long viewed as the earliest known bird. Archaeopteryx (dinosaurs → modern birds) Coelacanths = are considered living fossils between fish and tetrapods because it blends paired lobe fins that extend away from its body like Coelacanth (fish → tetrapods) legs and move in an alternating pattern, like a trotting horse. Platypus (reptiles →birds →mammals) Platypus = are considered living fossils because they are the ONLY egg laying and venomous mammal. (e.g., Jurassic mammal) D. Homology and Analogy as evidence of evolution Homologous structures? - same structure but different functions. (limbs of humans, cats, whales, and bats), indicating a common ancestor. What are Homologous structures? Analogous structure? same function but different structures. (wings in flying animals like bats, birds, and insects, to fins in animals like What are Analogous structures? penguins and fish), indicating different ancestor. Advance Biology For You 2nd edition pg. 217 There are many more other evidence for evolution in your notes! 3- Evolutionary Theories Suggestions, Examples and Prompts Linnaeus = →→→ Linnaeus = He believed that species were ‘immutable’ (Species do not and are unable to change over time). Curvier = →→→ Curvier = Developed his theory of catastrophes or catastrophism. -Earth has largely been shaped by several, sudden, short-lived, violent events. -Fossils show that animal and plant species are destroyed time and time again by many natural and violent events, and that new species evolve only after that.  S5 Biology Revision Notes 2024 (Version_18th_Nov, 2024) Lamarck = →→→ Lamarck = organisms alter their behaviour in response to environmental change. (Organism changed behaviour, in turn, modified their organs, and their offspring inherited those "improved" structures). Darwin = →→→ Darwin = that variation occurred randomly among members of a species; that an individual's traits could be inherited by its offspring; and that the struggle for existence would allow only those with favourable traits to survive. Neo-Darwinism = Darwinism + Mutation + Genetics Neo-Darwinism = Darwinism + the idea that Mutations + Mendelian Genetics all contribute to Natural Selection. (Advance Biology For You 2nd edition pg. 210) Modern Synthetic Theories of Evolution = a modern way to unify and comprehensively explain Neo-Darwinism Modern Synthetic Theories of Evolution (MSToE). Modern Synthetic Theories of Evolution = Neo-Darwinism + Key terms (Julian Huxley, 1942). Central Dogma of Molecular Biology = DNA → RNA Central Dogma of Molecular Biology = a theory stating that genetic information flows only in one direction, from DNA, to RNA, to protein, or → Proteins RNA directly to protein. What does "immutability of species" mean according "Immutability of Species" = an idea that each species of organism does not and cannot change. They all came into being (i.e., created) as what to Linnaeus? they are now. This idea was disproven by Charles Darwin's theory of evolution. Creationism = the belief that the universe and living organisms originate from specific acts of divine creation, as in the biblical account, rather than by natural processes such as evolution by Charles Darwin. Creationism totally disagrees with Darwinism. What does " theory of catastrophes or catastrophism " Fossils show that animal and plant species are destroyed time and time again by many natural and violent events, and that new species mean according to Curvier? evolve only after that. Evolutionary theories by Lamarck and Darwin Lamarck – environment caused variation; organisms adapted by ‘use and disuse’. Complete Biology IGCSE 3rd edition Chapter 3.25, pg. Darwin – environment selected variation; organism adapted by ‘chance’ *216 Explain today's Synthetic Theory of Evolution (MSToE) Population = a group of organisms of the same species. e.g. a population of finches or tortoise or iguanas etc. A population consists of a several individuals that breed with each other and produce a fertile young. A population is considered to be a "pool" of genes and gene types that are responsible for the genetic diversity of all the individuals within the group. (Key terms you should understand & use - Population; Individual; Mutation & Recombination; Selection; Individual = a member of a population Isolation; Origin of species) Random Mutation = sudden changes in the genes/alleles that parents pass on to their offspring. These changes may be good or bad. Either way is lead to variation. Variation = differences between individuals. This can be continuous variation (height, weight, IQ etc) or discontinuous variation (gender, blood group, eye colour etc) Recombination of genes = Sexual Reproduction leads to new combinations of genes/alleles, and this causes genetic variability. This is why you look different from your brother or sister even though you have same parents. Selection = Selective Pressure which selects the favourable characteristics  S5 Biology Revision Notes 2024 (Version_18th_Nov, 2024) Passing on genes (alleles) = offspring inherit genes over many generations Isolation = Any factors that breaks up a large original population into a smaller one and then isolates them. For example, geographical isolation would promote evolution of the original species inro different species. Isolation leads to the emergence of new species or speciation Species = individual that can breed with each other and produce a fertile young. Competition for Resources = without competition, organisms would not evolve. Competiton or the struggle for survival is a driving force Darwinsim. Origin of species by means of Natural Selection = -the diversity of organisms and their characteristics can be explained as the result of natural processes. -populations evolve over the course of generations through a process of natural selection 4- Variability and Selection Suggestions, Examples and Prompts Industrial Melanism (Peppered Moth) Industrial Melanism = (Advance Biology For You 2nd edition pg. 212) Black-colored moths were rarely seen because could be easily spotted by predators. During the industrial revolution, smoke polluted the environment and lichens disappeared. The tree trunks became black and the white-colored moths were replaced by the black-colored variety. Understanding Causes of Variability: Mutation and Genetic Variation is caused by. Recombination via Sexual Reproduction -mutation (which can create entirely new alleles in a population, some good and some bad), -random mating (males and female have several partners they mate with) -random fertilization (any of the millions of sperm produced by the male can fertile the egg that is periodically released by the female) - recombination (during meiosis, homologous chromosomes reshuffle their alleles and producing a variety offsprings with different characteristics. Understanding the meaning and consequences of Biological definition of Species = Isolation a group of organisms that can reproduce with one another in nature and produce fertile offspring. (→ emergence of new species) Speciation = (Advance Biology For You 2 edition pg. 215) nd a process where called new species arise In speciation, an ancestral species splits into two or more descendant species that are genetically different from one another and can no longer interbreed. Species separated OR isolated from each other can evolve separate species. A physical barrier, such as a mountain range or a waterway, makes it impossible for them to breed with one another. Examples of speciation are the Darwin’s Finches, Tortoise, Iguana etc Darwin’s Finches What is Adaptive radiation? (Advance Biology For You 2nd edition pg. 209) A process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available.