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survive and reproduce (pass on alleles and traits) The environment has limited resources, and those who can get more resources live longer to reproduce more. In fitness, offspring is always favored over survival or strength. Example: Almost dead zebra with 4 babies is more fit than the strong lion with no mate Fitness is directly related to adaptations, and is related to the environment Evolution of Organelles and Multicellular Beings ● Cells had membrane-bound organelles, like the nucleus and mitochondria/chloroplasts Cells realized that if they came together and worked in different ways, they could survive better Some cells moved the multicellular organism, while others made food for the whole organism in the middle Population Bottlenecks and the Founder Effect Population Bottlenecks: a small subset of a population survives after a large disturbance (natural disaster) and the allele frequency is very different from the original population Founder effect: subset of a population migrates to a new area and the allele distribution of the subset is different from the original population. Large genetic diversity generation 1 Original population Population bottleneck generation 2 generation 3 time Small genetic diversity generation 4 Bottleneck event surviving population Final population (recovery) Mother population Founder Effect New population Evidence of the Theory of Evolution Fossils The remains of organisms that had died a long time ago Bone remains, footprints, skin of organisms, insects naturally preserved Found in sedimentary rocks Relative Age Relative Age is found by the position of the fossil in the ground The deeper the older Absolute Age O Absolute Age is found by the ratio between carbon-14 and carbon-12 Carbon-14 is a radioactive isotope which undergoes radioactive decay, while carbon-12 doesn't Less carbon-14 means older Natural Selection An easy definition: organisms with heritable characteristics and traits that suit the environment survive and reproduce at a greater rate than organisms less suited to that environment Darwin hypothesized that this is how the different populations of finches evolved X Coevolution and rate of evolution ● Coevolution is when organisms evolve together Insect pollinators and flowering plants Rate of Evolution Gradualism is when organisms slowly evolve at a somewhat constant rate Darwin believed in gradualism Punctuated equilibrium is when organisms alternate between rapid evolution and dormant period of evolution Stephen Jay Gould proposed the theory of punctuated equilibrium John Baptiste Lamarck He hypothesized that organisms inherited acquired traits Theory of Use and Disuse Organisms had the ability to shapeshift their body little by little by using or not using them Example: He thought that because of giraffe's necessity to eat high-up leaves Example: The human appendix shrunk from its "previous size" because of disuse He also thought that organisms naturally became more complex as their adaptations increased Example: Plants became more complex as they started to photosynthesize to adapt to their environment Stanley Miller Performed one of the most important experiments of the last century Miller put all of early Earth's gases into a flask, and sparked* it, which caused a mild explosion. The more important part was that it produced: Glucose, amino acids, fatty acids, glycerol → starch, proteins, fats Guanine, Cytosine, Adenine, Thymine, Uracil →→ RNA and DNA Miller produced organic molecules from inorganic molecules This could why unicellular organisms evolved to respire *sparks in the experiment were fire sparks, but sparks in early Earth could have been volcanoes or lightning strikes, which were more common back then Types of Fossil Preservation Petrification Organisms fell into a body of water with many minerals which seeped into their body, turning their dead body into stone Amber Some insects from the age of dinosaurs were preserved in tree sap O Ice O Ice can freeze dead organisms, preserving DNA The wooly mammoth is an example Homologous Structure Different species of organisms that have a same structural component, suggesting that they all derived from a common ancestor. • Example: Bone similarities in forelimbs of mammals suggest common ancestry and support evolution Humerus- Radius Ulna Carpals Metacarpals Phalanges Human Bat Whale Cat Humerus Radius Ulna -Carpals Metacarpals Phalanges Alfred Russel Wallace Thought that all organisms evolved from common ancestors Planetary common ancestor He came to the same conclusion as Darwin, but he didn't have the resources to publish his results and findings Thomas Malthus He thought that organisms evolved because of the competition for resources Different species had evolutionary arms races Example: Bacteriophages and bacteria Variation Variation between each organism is required Genetic Diversity Example: If a disease that attacked people with weaker tissue cells spread, and everyone had these weaker tissue cells, we would be wiped out Variation is heritable This variation is important because some organisms will be better at survival and reproduction ● Natural selection promotes variation Evolution is still a theory! *But it still establishes some facts! Genetic Variation Genetic Variation is the difference(s) in DNA sequences among organisms of the same species. This can be from mutating or sexually reproducing. These mutations would have to occur in gametes for the mutations to pass onto offspring Organisms with certain alleles will be favored to pass on their variations to the next generation (organism is naturally selected) O Example: Unicellular organisms fought for resources in the seas in early Earth Eventually, some of them mutated to where they were able to use diffused CO₂, channeled water, and captured light rays to make energy and food rather than fighting for it This mutated group of organisms thrived and reproduced at a greater rate than the group of organisms that fought for resources Evolution AP Biology CONVERGENT EVOLUTION Streamlined Shape due to Aquatic Environment (Shared Selection Pressure) SHARK CHONDRICHTHYES • Cartilaginous Skeleton Gills Scale Denticles in Skin DIVERGENT EVOLUTION Branching of Vertebrata into Mammalia and Chondrichthyes DOLPHIN VERTEBRATA Vertebrae Cranium Tri-Partite brain MAMMALIA • . . PUMA Bony skeleton Lungs Mammary Glands Early Earth Earth as of today has an atmospheric composition of mostly nitrogen and oxygen. However, back then, the atmosphere contained: Methane Ammonia Hydrogen Gas Hydrogen Cyanide CO₂ CO Hydrogen Sulfide NO OXYGEN Mostly inorganic molecules, apart from methane The atmosphere was essentially poisonous to humans today. Behavioral Adaptations Behavioral adaptations are traits that change the way that an organism acts to optimize survival and fitness. Some examples of behavioral adaptations are Monarch butterflies migrating Salmon all group up in one part of a stream in order to mate Salmon do not have a council meeting beforehand, they just do it once they sense that it is that time of year Migration is the most common type of behavioral adaptation Physiological Adaptation Physiological adaptations are traits that make an organism's body go under a body process that optimizes survival and reproduction. Some examples of this are: When your hands come in contact with water for long periods of time, your hands have a different sort of texture on them This is so your body has a better grip underwater The King Cobra produces venom when hunting O The venom paralyzes the prey, making it easier for consumption and capture When you have a stroke, your body pumps more blood to your brain This is because the brain has top priority, as there is a blood clot or obstruction blocking blood flow to the brain in one of the arteries Analogous Structure This is the similarities in functions of different species of organisms, suggesting convergent evolution. Dolphins and sharks have similar niches in the environment, but dolphins are mammals while sharks are fish. This is an example of convergent evolution. Dolphin (Cetacean) MAMMALS Ichthyosaurus (Fossil reptile) REPTILES Shark (Condrictian) FISH Evolution of Life Oparin's Heterotroph Hypothesis Life stemmed from nonlife OOO O First cells were heterotrophs, getting food from the environment Were anaerobes, due to the lack of oxygen CO, increased due to it being a waste product of ferment....... Competition among cells for food started A mutation happened Some cells could now intake water, CO₂ and light rays to produce food on their own The photosynthesis produced OXYGEN Evidence that oxygen was produced Layers of iron had rusted due to reactions with oxygen The mutants mutated again to use oxygen to produce way more ATP (36 vs. 2) Structural Adaptation Structural adaptations are traits that change an organism's build or structure in order to increase its survival chances and reproduction. Some examples are: The King Cobra has a hood This is an extension of muscles and bones in order to look more intimidating to other predators Humans have both flat and sharp teeth Since humans are omnivores, they use flat teeth for eating plants and sharp teeth for eating meat Ducks have webbed feet This is so that they can paddle through the water easier A stone fish looks like the ocean floor O The fish can blend in and wait for prey, or hide from predators Mimicry and Camouflage are more common examples