Evolution and Ecology Overview

Evolution

• Evolution is the change and adaptation of organisms to their environment over time for survival.
• Key figures in the concept of evolution include Darwin and Wallace; numerous other figures contributed to the field.
• Many indigenous cultures have beliefs that reflect evolution.
• Ecology is the study of interactions between organisms and their environment.
• Adaptation is how organisms change to fit their environments.
• Fitness is the suitability of an organism to their environment.
• The history of ecology is often based on Western philosophy, but indigenous communities also studied ecology long before.
• The information on evolution and ecology is crucial for understanding how fields of study develop and evolve.

Misconceptions About Evolution

• Evolution is not just a theory about the origin of life; it is a theory of how organisms change over time.
• A theory is a claim (a hypothesis) that can be potentially proven.
• Humans did not evolve from monkeys but share a common ancestor.
• Evolution does not always lead to more complex organisms; organisms may also lose traits they no longer need.
• Evolution is not goal-oriented; organisms do not evolve because they need to; beneficial traits enhance survival and reproduction.

Science and Religion

• Science and religion can be independent, complimentary or in conflict.
• Science and religion do not always contradict.

Phylogenetic Trees

• Evolutionary relationships are displayed in phylogenetic trees.
• Phylogenetic trees show similarities in traits or genetic information.
• Phylogenetic trees show how organisms are related to each other.
• Phylogenetic trees demonstrate that evolutionary changes affect organisms in diverse ways which are not always linear.

Clades

• A clade includes a common ancestor and all its descendants.
• Clades are nested within larger clades.
• There are several types of grouping, such as Monophyletic, Paraphyletic and Polyphyletic groups.

Evolution Mechanisms

• Mutation: Changes in nucleotide sequences (substitutions, deletions, insertions, inversions) leading to variation within an organism.
• Non-Random Mating: organisms mating based on their traits.
  • Assortative Mating: Preference for similar traits.
  • Disassortative Mating: Preference for different traits
• Gene Flow: Introduction of new genotypes into a population through migration.
• Genetic Drift: Change in allele frequencies due to random chance events.
• Genetic Drift (Founder Effect and Bottleneck Effect): occurs in smaller populations due to chance events. The loss of genetic variation can reduce likelihood of survival.
• Natural Selection: Organisms with traits best suited to their environment are more likely to survive and reproduce.

Types of Natural Selection

• Directional Selection: Favors one extreme phenotype.
• Stabilizing Selection: Favors the intermediate phenotype.
• Disruptive Selection: Favors both extreme phenotypes.

Hardy-Weinberg Equilibrium

• Allele frequencies remain stable in a population not evolving.
• Population can remain consistent over generations, but it does not always mean the population is not evolving.