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HSC Biology | Free Study Notes In this lesson what alleles are the difference between genotype and phenotype what dominant and recessive mean how Mendelian inheritance works how to use Punnett squares What is Mendelian inheritance? Mendelian inheritance is the basic pattern of inheritance first described by Gregor Mendel. It explains how characteristics are passed from parents to offspring through alleles. At this level, Mendelian inheritance mainly refers to traits where: on

HSC Biology | Free Study Notes In this lesson how mutation creates new alleles how meiosis produces variation what crossing over does what independent assortment means how fertilisation increases variation Why genetic variation matters Genetic variation means differences in genetic information between individuals. This variation is important because it: makes individuals different from one another provides the basis for natural selection helps populations respond to changing

HSC Biology | Free Study Notes In this lesson what transcription is what translation is the roles of mRNA and tRNA what codons are how ribosomes are involved in polypeptide synthesis Why transcription and translation matter DNA stores genetic information, but proteins are the molecules that carry out many important cell functions. Cells need a way to: use the code in DNA transfer that code to the ribosome build a chain of amino acids in the correct order This happens through:

HSC Biology | Free Study Notes In this lesson what semi-conservative replication means how complementary base pairing is used how DNA is copied why accurate replication matters how replication supports continuity of genetic information What is DNA replication? DNA replication is the process by which DNA makes an exact copy of itself before cell division. This is important because: new cells need genetic information daughter cells must receive DNA heredity depends on genetic i

HSC Biology | Free Study Notes In this lesson what nucleotides are how base pairing works why DNA is described as a double helix what the sugar-phosphate backbone is why DNA structure matters in heredity What is DNA? DNA is the molecule that stores genetic information. This genetic information: carries instructions for inherited characteristics is passed from one generation to the next provides the code used in protein synthesis Nucleotides DNA is made of repeating subunits c

HSC Biology | Free Study Notes In this lesson the purpose of meiosis what reduction division means the main stages of meiosis how gametes are formed how meiosis creates variation What is meiosis? Meiosis is a type of cell division that produces gametes with half the chromosome number of the original cell. These gametes are used in sexual reproduction. Why meiosis matters Meiosis is important because it: forms sperm and eggs in animals forms gametes in plants reduces chromosom

HSC Biology | Free Study Notes In this lesson the purpose of mitosis how chromosomes behave during mitosis the main stages of mitosis why mitosis is important in growth and repair What is mitosis? Mitosis is a type of cell division that produces two genetically identical daughter cells. It happens in body cells and is used when an organism needs to: grow repair damaged tissue replace worn-out cells reproduce asexually in some organisms A useful exam point is that mitosis keep

HSC Biology | Free Study Notes In this lesson how fungi reproduce by budding and spores how bacteria reproduce by binary fission how protists reproduce by binary fission and budding how these methods support continuity of species why asexual reproduction is effective in many microorganisms Why reproduction matters in microorganisms Fungi, bacteria and protists must reproduce to: continue the species increase population size spread into new environments survive over time In th

HSC Biology | Free Study Notes In this lesson what pollination is what fertilisation is how seeds are formed how plants reproduce asexually why plants use both sexual and asexual reproduction Why reproduction matters in plants Plants need to reproduce to: continue the species pass genetic information to the next generation survive across changing environments Plants can reproduce in two main ways: sexually asexually Pollination Pollination is the transfer of pollen from the

HSC Biology | Free Study Notes In this lesson the key differences between internal and external fertilisation animal examples of each the survival implications of each method why each method suits different environments What is fertilisation? Fertilisation is the fusion of male and female gametes to form a zygote. In animals, fertilisation can happen in two main ways: internal fertilisation external fertilisation Internal fertilisation Internal fertilisation happens when the

HSC Biology | Free Study Notes In this lesson what sexual reproduction is what asexual reproduction is the main advantages and disadvantages of each examples of each in different organisms why reproduction matters for continuity of species What is reproduction? Reproduction is the process by which organisms produce offspring. It is important because it allows: continuity of the species transfer of genetic information from one generation to the next populations to persist ov

HSC Biology | Free Study Notes In this lesson what rehabilitation means in ecosystem management how biodiversity can be managed what sustainability means in ecosystems what future threats ecosystems may face why conservation matters Why ecosystems need conservation and management Ecosystems can be damaged by: habitat destruction pollution introduced species climate change overuse of natural resources If ecosystems are not managed carefully, biodiversity may decrease and impo

HSC Biology | Free Study Notes In this lesson what extinction means how environmental change affects ecosystems how species replacement can happen what long-term trends in ecosystems look like why ecosystem change over time matters in Module 4 Why ecosystems change Ecosystems are not fixed. They change over time as abiotic and biotic conditions change. These changes may happen: over short time periods, such as after drought, fire or disease over long time periods, such as cli

HSC Biology | Free Study Notes In this lesson how fossils provide evidence about past life how rock records show past environmental change how ice cores preserve evidence from the past how pollen helps reconstruct past vegetation how scientists reconstruct past environments Why scientists study past ecosystems Past ecosystems help biologists understand: how environments have changed over time how organisms responded to changing conditions how abiotic and biotic factors shape

HSC Biology | Free Study Notes In this lesson how graphs are used in ecosystem studies how to identify trends and patterns what anomalies are how to draw valid conclusions from data how to avoid common mistakes when interpreting results Why ecosystem data needs interpretation Collecting data is only one part of ecology. Biologists must also interpret what the data show. Interpreting ecosystem data helps students: describe changes in populations compare habitats identify relat

HSC Biology | Free Study Notes In this lesson what quadrats are used for what transects are used for why sampling is needed in ecosystem studies what validity means in fieldwork what reliability means in fieldwork Why fieldwork matters in ecosystems Ecosystems are too large and complex to study by observing every single organism. Fieldwork helps biologists: estimate population size compare different areas detect patterns in species distribution investigate relationships betw

HSC Biology | Free Study Notes In this lesson what a habitat is what an ecological niche is how a niche includes a species’ role in the ecosystem how competition relates to niches what niche overlap means What is a habitat? A habitat is the place where an organism lives. A habitat provides the environmental conditions an organism needs, such as: shelter food or energy sources water suitable temperature space for reproduction Important point A habitat is mainly about where an

HSC Biology | Free Study Notes In this lesson what limiting factors are what carrying capacity means how populations change over time how examples can be explained using ecosystem factors What is population size? Population size is the number of individuals of one species in a particular area at a particular time. Population size can change because of: births deaths immigration emigration In ecosystems, population size is not fixed. It changes in response to environmental con

HSC Biology | Free Study Notes In this lesson what abiotic factors are what biotic factors are how temperature, rainfall and light affect ecosystems how competition, predation and disease affect populations why these factors matter in ecosystem dynamics What are abiotic factors? Abiotic factors are the non-living parts of an ecosystem. These are physical and chemical conditions in the environment that affect where organisms can live and how well they survive. Module 4 specifi

HSC Biology | Free Study Notes In this lesson what an ecosystem is the roles of producers, consumers and decomposers how food chains show feeding relationships how food webs show interdependence why organisms in ecosystems depend on one another What is an ecosystem? An ecosystem is a community of organisms interacting with each other and with their physical environment. An ecosystem includes: biotic factors, such as plants, animals, fungi and bacteria abiotic factors, such as