Practical Skill: Investigating the Effects of Random Sampling on Allele Frequencies Investigations to mimic the effects of random sampling on allele frequencies in a population can be devised using...
Edexcel IGCSE Biology 复习笔记 2.6.2 Types of Respiration Aerobic Respiration Aerobic respiration requires oxygen It is defined as the chemical reaction in cells that uses oxygen to break down nutr...
Allopatric & Sympatric Speciation Evolution causes speciation: the formation of new species from pre-existing species over time, as a result of changes to gene pools from generation to g...
Reproductive Separation Reproductive separation In order for evolution to occur the new species population must be genetically and reproductively separated from the pre-existing species popu...
Evolution The allele frequencies (within the gene pool) of a population can change over time due to processes such as natural selection When the allele frequencies of a population change suf...
Types of Selection & Their Effects Environmental factors that affect the chance of survival of an organism are referred to as selection pressures For example, there could be high levels ...
Edexcel IGCSE Biology 复习笔记 2.6.1 Energy ATP Organisms need energy for things such as: Chemical reactions to build larger molecules from smaller molecules Muscle contraction to allow move...
Selective Advantage Every individual within a species population has the potential to reproduce and have offspring In reality, however, there are many environmental factors that prevent ever...
Natural Selection Every individual within a species population has the potential to reproduce and have offspring which contribute to population growth If all the offspring of every individua...
Edexcel IGCSE Biology 复习笔记 2.5.12 The Energy Content of Food Practical: Energy Content of a Food Sample We can investigate the energy content of food in a simple calorimetry experiment A...
Edexcel IGCSE Biology 复习笔记 2.5.11 Absorption Absorption of Food & Water The Stages of Food Breakdown Food taken into the body goes through several different stages during its ...
Edexcel IGCSE Biology 复习笔记 2.5.10 Humans: Bile Bile Production Bile is an alkaline substance produced by cells in the liver Before being released into the small intestine bile is stored ...
