Week 1 (23.1, 23.2,23.3)

• Natural selection is the process by which certain traits become more or less common in a population over time due to their impact on reproductive success.
• Biological Evolution refers to the changes in one or more characteristics of a population from one generation to the next.
• Microevolution involves changes in a single gene or in allele frequencies in a population over time.
• Macroevolution refers to the formation of a new species or groups of related species.
• Changes in chromosome structure and number may affect the ability of two organisms to breed with one another - important in the establishment of new species.
• Human cells have 23 pairs of chromosomes while the others have 24.
• Evolution is a theory as it is supported by a substantial body of evidence while explaining a wide range of observations.
• Evolution aims to explain the diversity of life and scientific knowledge.
• Molecular Evolution refers to the process of evolution at the level of genes and proteins.
• Comparisons of gene or protein sequences in different organisms can reveal evolutionary relationships that cannot be seen in morphology.
• The term Empirical thought relies on observation to form an idea or hypothesis rather than trying to understand life from a non physical or spiritual point of view.
• John Ray, an English naturalist, was the first scientist to carry out a thorough study of the living and developed an early classification system for plants and animals based on anatomy and physiology.
• Carolus Linnaeus, a Swedish Naturalist, expanded John Ray's systematic classification of plants and animals.
• Georges Buffon, a French zoologist, proposed that populations of living things change through time but was careful to hide his views.
• Jean-Baptiste Lamarck, a French naturalist, suggested an intimate relationship between variation and evolution and discovered that some species remained the same over the millennia but some changed by examining fossils.
• Georges Cuvier, a French Zoologist, proposed that Earth has been shaped by sudden, violent events, and that the planet was about 6,000 years ago.
• James Hutton, a Scottish geologist, and Charles Lyell, a Scottish geologist, proposed that changes in the Earth are directly caused by recurring events.
• Thomas Malthus, an English Economist, proposed that population growth tends to increase exponentially, leading to situations where resources are insufficient to support the population.
• Convergent Evolution: two species from different lineages have independently evolved similar characteristics as they occupy similar environments.
• The first placental mammals evolved much later after Australia drifted away resulting in Australia to lack larger, terrestrial placental mammals.
• Australia being isolated resulted in unique species that are not placental mammals.
• Australia was more than 100 species of marsupials, mammal species whose offspring are born underdeveloped and then developed in their mother’s pouch.
• The tetrapods gave rise to the three main groups of modern tetrapods: Amphibians, Birds and Moder Reptiles, and Mammals.
• The theory of evolution explains that bone structures are modified for different functions due to natural selection despite originating from a common ancestor.
• In 2005 Paleontologists Ted Daeschler, Neil Shubin, and Farish Jenkins found fossils of Tiktaalik Roseae, which illuminated the evolution of tetrapods.
• Developmental Homologies are revealed during early stages of embryonic development in certain organsims such as vertebrates.
• Different species being evolved in similar structures for survival due to demands from environment.
• Cetacea is an order of aquatic animals that included whales, dolphins, and porpoises, and is a representation of whale evolution.
• Placental mammals arose some place else and was unable to migrate to Australia as the ocean served as a barrier.
• Tiktaalik Roseae represents an intermediate state of ancestral form to the form of its descendants.
• Molecular Homologies are similarities between organisms at the molecular level due to descent from a common ancestor or an interrelated group of ancestors.
• Fossils provide detailed information regarding evolutionary change of related organisms as they are evidence of life history.
• Vestigial Structures are anatomical features whose function is reduced or absent but that resemble structures of their presumed ancestors, another result of evolution.
• Endemic species are plants and animals that are only found in particular locations naturally.
• The first evidence of biological evolution comes from fossil record studies, the distribution of related species on our planet, selective breeding experiments, and the comparison of similar anatomical features in different species.
• Most foods we consume, such as fruits, vegetables, meat, etc., are obtained from species that have been modified by selective breeding.
• Additional elements of evolution can be found at the molecular level, such as comparing DNA sequences from different species to gain knowledge into the evolution of species and its relation to the associated changes in the genetic material.
• Isolated continents, such as Australia, have major animal groups that are also in connection to the changes in landmasses on Earth.
• Heritable variation in traits may occur among individuals of a given species and passed from parent to offspring.
• Biogeography: the study of the geographic distribution of extinct and living species indicates that species in a given area have evolved from pre-existing species.