theSciencyStuff

First of all, we still don't really know why sex developed in the first place. I mean for all the longtime singles out there, who desperately want a baby to give on their genes to the next generation (if you really just want to reproduce... uhm, maybe go and see a psychologist first?)  - things would be so much easier if they could just duplicate themselves. Voilá - perfect copy. But you see, the problem here is - it's just a copy. There is nothing new about it. This might work for now for you, but we live in an ever-changing world . Technology changes and if you don't adapt, you will find yourselves as clueless about gadgets just like your grandma when you first tried to explain to her how CSGO Players talk to each other via teamspeak in-game. But no innovation isn't the only problem. What if your genome suffers a deleterious mutation ? You can't go to one of your other clones, that didn't have that mutation and say "Oi, give me that, mine b...

Mutation The ultimate cause of all genetic variation is mutation. It occurs either during replication or under the action of a mutagenic agent, i.e. a chemical or radiation. They can happen in somatic cells and in germ -line cells, but only mutation in germ-like cells have an evolutionary consequence. There are a larger number of cell divisions involved in the male sperm line than in the female germ line, therefore more new mutations are transmitted through sperms than eggs. The different types of mutation can be distinguished: Gene mutations: a) Point mutation : one base mutates to another b) Frameshift mutation : insertion/deletion of a single base/short stretch of nucleotides, which shifts the whole reading frame Chromosomal mutations c) Duplications/deletions : “in-dels”, possible due to slippage or unequal crossing-over d) Inversions : reversal of DNA order e) Translocation : exchange of segments among non-homologous chromosomes f) Fissions/Fusions : chromosomes ...

Okay, this one is not a complete summary, but rather a How-To for Population Equilibrium. Should take about 5mins! Hard-Weinberg Equilibrium The Hard-Weinberg-Principle is mostly used to count and calculate population, but with the side note, that the population we want to work with, is an ideal population. There is no evolution, no natural selection, we just look at the state the group of animals is like, at this very moment. The HWE itself is simple, it looks like the binomic equation you probably got to know in high school. Our population is a bunch of sheep, 1000 to be frank. Of those sheep, 18 are black - black being recessive, the other 982 sheep are grey-ish. Now I want to know how many of those are pure grey sheep and which are heterozygous grey-ish-black-ish sheeps .___. Because we look at all possible constellations for 2 allele (p and q), there are 3 possible phenotypes: (p + q) x (p + q) ==> p^2 (black) + q^2 (grey) + 2pq (grey-ish-black-ish BUT THEY LOOK FUCKING ...

Paleoevolution & Fossil Records Fossiles are defined as trace of past life - such as body parts, footprints and moulds, left as indents of organic matter or other kinds of thinkable traces. Fossilisation can only occur if remains of animals are covered by sediments ( sedimentation ) before they decay ( microbial action, scavengers ). The fossil must be preserved and eventually found. The change for any organism to leave a fossil is therefore generally very unlikely and depends on: where organism lived - within sediments better than elsewhere - surface sediment > water column - marine > terrestrial type of organism - large > small - have skeletons/shell > soft bodied forms Geologists use relative and absolute techniques to date events. Radiometric dating infers the absolute geological time: It uses radioactive decay of isotopes (rubidium isotope 87Rb decay into strontium isotope 87Sr with a half-life(HL) of 48.6 x 10^9 years) Radioactive decay proceeds ex...

This little series here covers the summaries I write for my EvoGen lectures, maybe somebody finds them helpful :) Evidence for Evolution Definition - the development from a simple to a complex formed organism (i.e. Procaryotes => Eucaryotes) Lamarckism - theory of soft inheritance, inheriting traits that an organism acquired during its lifetime and passing it on to its offspring Darwin 1) Final genetic process - Speciation; phylogenetic tree 2) The main mechanism of evolution is natural selection Evolution is a phylogenetic process In order to demonstrate Evolution in the sense of Darwin, there are 3 Points that need to be shown: Species can go extinct Species can change over time Species trace back to a common ancestor Three lines of evidence that can be used to prove these points are 1) Fossil record, 2) Embryology & Anatomy, and 3) Biogeography Extinction of Species The main source for the fact that species can go extinct, comes from the fossil record...