EEMB Study Guide PDF

Evolution: How organisms change and adapt to their environment over time for better survival. Survival of the fittest, natural section. There were many “founders” of the concept of evolution, Charles Darwin being the most known, but Alfred Wallace also thought of this conception (“histor...

Evolution: How organisms change and adapt to their environment over time for better survival. Survival of the fittest, natural section. There were many “founders” of the concept of evolution, Charles Darwin being the most known, but Alfred Wallace also thought of this conception (“historical sketch” gives credit to these founders, there are more than 70). Many indigenous cultures around the world held beliefs that reflected beliefs of evolution. Ecology: Interactions between organisms and their environment. Adaptation: How organisms change to fit their environment Fitness: How suitable an organism is to their environment The history of ecology that is taught is based on “western” philosophy, but indigenous communities were studying the ecology of land and sea long before. Hypothesis of a kelp highway. The information we covered this week is important for understanding Evolution and Ecology because it is important to recognize the narratives and origin of a field of study to better understand their principles and teachings. The history of ecology and evolution helps me to understand that as humans that interact daily with our environment, our interactions are actually super important and it is not a new concept but rather one that has been developing for thousands of years by other scholars or even tribes. ​ When we talk in English, we often refer to living organisms such as plants as “it” and by doing so we put them in a separate category, not living. This is an ability to objectify. ​ Indigenous people held controlled fires in the forests to care for the ecosystem until they were banned, after colonization there were a lot of trees in the forest, little care about the ecosystem. Science: The study of the world around us, atoms, biological organisms and theories to explain the physical world. Body of knowledge and a process by which we understand the physical/ natural world. Religion: the belief in a Creator, belief in a spiritual world. Structured systems of beliefs. How do science and religion overlap, or not? ​ -​ The Galileo Affair consisted that the Earth was not the center of the universe that it revolves around the sun Misconceptions about Evolution Actually, Evolution is just a theory, it is not proven. It is a theory about the origin of life, about how organisms change over time. ​ A theory is a claim, a hypothesis but causation cannot be proven. ​ There can be so much evidence to prove a claim (closest thing to a fact) Misconceptions: ​ “Humans evolved from monkeys” ○​ Well we share a common ancestor but did not evolve directly from one another ​ “Evolution always leads to more complex organisms” ○​ Sometimes organisms lose traits that are not of need for them such as cavefish that lose their sight because they don’t need to fight off prey. They can use their energy in another area. ​ “Organisms evolve because they need to” ○​ Evolution is not goal-oriented ○​ Sometimes they don’t need to evolve, but it might be more favorable if they do in terms of investing their energy in another areas. Some organisms will be well off with or without a trait because sometimes that trait isn’t needed so then it evolves to get rid of it. ○​ Evolution occurs as a result of natural selection to enforce FAVORABLE TRAITS ​ “Organisms can evolve during their lifespan” ○​ Populations, not individual organisms evolve when they undergo genetic change ​ “The fittest are the strongest” ○​ The fittest individuals are the most adapted to their environment not necessarily physically the strongest ​ A) I chose to dig into the misconception "Evolution is a theory about the origin of life" because every time I hear a conversation about evolution it is in the context of the origin of humans and how we were created/ where we originated from. ​ B) The corrected misconception is that the theory of evolution does not encompass how life originated rather how it evolved and changed after its origin. This alters how someone understands evolution because instead of seeing it as a debate between science and religion in terms of how life came to be, it can be approached as a field of study where we can use fossils and understanding of our environment to understand how new organisms came to be. Phylogenetic Trees and Patterns That Help us Understand Evolution -​ Evolution has a lot of changes over the years, lots of variations within families of organisms Phylogenetic Tree: a diagram that shows evolutionary relationships among organisms based on similarities in their traits or genetic information -​ A hypothesis about relationships because they’re continually changing (even today) ​ Trees aren’t ladders, not every change in between lead to one ultimate organism, rather the branching of many ○​ Addresses misconceptions of hierarchy, “more progressed is better” Clade: a grouping that includes a common ancestor and all the descendants of that ancestor. ​ Clades are nested within larger clades Sister Group: 2 different organisms/ groups that share a common ancestor that are each other’s closest relatives Organisms seem closer when other organisms are excluded, as some, most, are extinct. They are context specific Monophyletic group: A common ancestor and all descendants of that ancestor Paraphyletic group: A common ancestor and some, but not all, of the ancestor’s descendants. Polyphyletic group: Does not include the common ancestor of the group. ​ There independent lines of evidence for evolution such as comparative anatomy, embryology and development, fossil record, DNA​ comparisons, species distribution, evolution observed, predictive power of evolution, and nested hierarchies of traits. 4. The information we covered this week is important for understanding Evolution and Ecology because phylogenetic trees address common misconceptions such that evolution is linear. Phylogenetic trees help us understand how the divergence of so many organisms came about but also how we can trace organisms to their ancestors and understand how they are related. ​  Evolution happens by: Mutation: Changes in the nucleotide sequence; Substitutions, Deletions, Insertion, and Inversions ​ Mutation leads to change in allele frequency ​ Allele frequency: How common an allele is at a given population ​ ​ Frequency of A= number of allele A/ total number of A/a alleles Non-Random Mating: Organisms may mate with others of the same or different genotypes -​ Assortative Mating: Preference for a similar geno/phenotypes -​ Disassortative Mating: Preference for different geno/phenotypes * Non Random Mating may lead to a decrease in heterozygous genotypes because the combination of big A and small a is lost * Gene Flow: The introduction of a new genotype to a population that didn’t have genotype present before. Migration ​ Genetic Drift: Describes changes in allele frequencies due to random chance events. ​ Ex. you squash all of a specific type of beetles on the sidewalk. Small populations are greatly affected by genetic drift, but not large populations. 2 flavors of genetic drift that leads to a loss of genetic variation -​ The Founder Effect: When a small subset of a larger population is used to establish a new population. -​ Bottleneck Effect: A random event that significantly reduces the population size. -​ Natural disasters, diseases Biological fitness: ability of an individual to produce surviving, fertile offspring relative to that ability in other individuals in a population Natural Selection: A process by which organisms with traits that are better suited to their environment are more likely to survive and reproduce. ​ -​ If evolution is occurring, there is an increased frequency of a specific genotype, hence there being less genetic variation. Directional Selection: One extreme phenotype is more fit than all the other phenotypes Stabilizing Selection: intermediate phenotype being more fit than the extreme ones. ​ Birds laying just the right amount of eggs Diversifying/ Disruptive Selection: Both phenotypes are more fit than those in the middle Hardy-Weinberg equilibrium: tells us when evolution is not occurring and therefore there is no change in genotype or allele frequencies over time. ​ Allele frequencies will remain stable in a transition state. Equilibrium equation tells us evolution is not happening when a population’s allele frequencies remain constant across generations Channel Island Foxes: -​ Founder and Bottleneck Effect -​ Eagles ate them -​ Less variation -​ The information we covered this week is important for understanding Evolution and Ecology because we can better understand that evolution does not just arise from a specific case but there are many contributing factors that can cause it. To understand the mechanisms of evolution helps us understand why many organisms evolve and what that means for the population and the environment that they are in. It is also helpful in understanding that sometimes evolution can be caused by random chance events and it is not always a positive evolution nor is natural selection the developing the most complex organism. -​ -​