Evolution & Natural Selection PDF

Evolution & Natural Selection WHO IS CHARLES DARWIN? Born in England in 1809, Darwin was a nature lover who graduated from Christ’s College with a bachelor of arts in 1831. His botany professor recommended him for a naturalist position on the HMS Beagle, which would take him on the voyage of a lif...

Evolution & Natural Selection WHO IS CHARLES DARWIN? Born in England in 1809, Darwin was a nature lover who graduated from Christ’s College with a bachelor of arts in 1831. His botany professor recommended him for a naturalist position on the HMS Beagle, which would take him on the voyage of a lifetime. Darwin published On The Origin of Species, which solidified him as the father of evolutionary biology. He died in 1882. WHO IS CHARLES DARWIN? Darwin obtained a naturalists position aboard a ship called the HMS Beagle which was captained by Robert FitzRoy. The trip would last five years and take him around the world. During this time, Darwin collected plant, animal and fossilized specimens and was able to closely observe the biological principles he learned in school. WHO IS CHARLES DARWIN? Darwin’s trip on the HMS Beagle lasted from 1831-1836. His favourite location included the Galapagos Archipelago found off the coast of South America. He spent five weeks there, and his findings were instrumental in developing his scientific theories. He discovered that the unique animals of the mainland and many islands were similar to one another. This led him to wonder about their origins – how did they get there, and why did they vary just slightly from one another, depending on their location? WHO IS CHARLES DARWIN? Darwin specifically studied finches which were eventually named after him. He determined that the finches varied from place to place because they all descended from a common ancestor on the mainland. Because the birds were isolated on the different islands with various types of foods and climates, new populations were formed, causing them to evolve into the thirteen different finch species. WHO IS CHARLES DARWIN? It took Darwin 20 years to explain WHY organisms evolved using his theory of Evolution by natural selection. Natural selection is where species that are best adapted to their environment will survive and reproduce which increases the strength of the species, while those that fail to adapt and reproduce die off. Darwin wrote about this in 1859 in On the Origin of Species by Means of Natural Selection where he backed up his theory using the fossil record, embryology and other factors. Darwin’s Finches Charles Darwin set off on the HMS Beagle on December 27, 1831. On September 7, 1835, they set off from Peru and reached one of the first Galapagos Islands on September 16 – Chatham Island. Darwin collected species of tortoise, mockingbirds, turtles, snakes, sea and land iguanas, and various other birds including his finches. On October 20, his famous voyage came to an end as he set sail to Tahiti over 3,200 miles away. Darwin’s Finches However, while visiting the Galapagos, Darwin discovered 13 unique finch. All are said to be descended from one species that may have blown from the mainland of South America during a windstorm over a million years ago. Darwin collected multiple species of finch from the Galapagos and began to see how diverse they were from island to island – their beak shape and function seemed to relate to the foods they ate depending on the environmental factors present on each island. Darwin’s Finches One major commonality of all the finches is their beak coloration – black for breeding finches and yellow for those that aren’t ready or able to breed. This suggests their relation to a common ancestor. Darwin’s finches or Geospizinae belong to one of several finch categories: Darwin’s Finches – Warbler Finches: Certhidae: Once thought of as an actual warbler due to its physical characteristics and song, Darwin was told upon his return from his trip that it was in fact a finch. They feed primarily on insects using their probing beak. It is the most widely spread species in the Galapagos and inhabits the forests and highlands of the islands of Narborough. Darwin’s Finches – Cactus/Ground Finches: Geospiza: ground finches have large, short, crushing beaks meant for cracking nuts to get food. They typically live in tropical forests and shrubland and spend their days foraging the ground and low vegetation for food. They can be found on Chatham Island. The large ground finch is considered to be on the brink of extinction. Darwin’s Finches – Vampire Finch: The most ancestral form of all of Darwin’s Finches is the Vampire finch which is native to Wenman and Culpepper Islands. It pecks at the skin of blue footed boobies and drinks their blood. It is believed they developed this feeding habit from eating parasites off of birds. Darwin’s Finches – Tree Finch: Camarhynchus: these birds have a small, sharp beak which allows them to feed primarily on insects in trees. They are found on the islands of James and Indefatigable. Darwin’s Finches – Vegetarian Finch: Platyspiza: found in dry forests and humid mountain forests, these finches are one of the largest and feed on flowers, buds, bark, and fruit of trees. It can be found on Bindloe. Mutation Nation What is a Mutation? Any change in the DNA of an organism Are mutations good or bad? Mutations can be both good or bad, or they can have no effect at all. Good – webbed feet on a duck Bad – Skin cancer No effect – Blue or Brown eye color Mutation Nation Earth is approximately 4.6 billion years old, and the planet has changed a great deal during its existence. For organisms to survive, they would have to change (mutate) also. A mutation is any permanent change in the DNA of a gene or chromosome. Some mutations are BAD, some can be GOOD and some don’t really have any effect. Mutation Nation Examples of Mutation: Albinism …the absence of pigmentation within the skin – true albinos have pink eyes due to the flow of blood to the retina and the absence of pigment within the iris…  Mutation Nation Examples of Mutation: Flu Virus …every year, scientists that study the flu virus must devise a new vaccine to combat the current strain of flu going around. The flu virus mutates often so new vaccines must be created each year… © Getting Nerdy, LLC  Mutation Nation List three more mutations - other than Albinism and Flu virus - that exist in nature, and whether they are good, bad or neutral. © Getting Nerdy, LLC  Mutation Nation Some mutations lead to adaptation… When a mutation is beneficial and helps an organism to survive in its environment, the organism has the opportunity to live longer, find a mate, and pass on its good traits to its offspring. How are a zebra’s stripes considered a helpful mutation? A zebra’s stripes allow it to confuse predators when traveling in herds. This allows them to survive another day to pass on their traits during reproduction. © Getting Nerdy, LLC  Mutation Nation An adaptation is a characteristic that helps an organism survive and reproduce in its environment. They include structures and behaviors for finding food, a mate, for protection, and for moving from place to place. © Getting Nerdy, LLC  Can you list some adaptations of the animals below? Large ears to hear predators Powerful back legs for jumping long distances Have special hairs on Jaw that can “unhinge” to swallow prey whole Pouch for carrying their back which they young until they are can release when under Basks in the sun to able to survive on their attack to irritate the warm cold-blooded own eyes and nose of body predators Can “smell” with it’s Can easily sense tongue vibrations in the ground Adaptation: behavior or characteristic for Have opposable survival Trunk used to bathe, thumbs for grasping drink and wash items themselves Prehensile tail for Has spots that camouflage Large tusks for defense hanging from trees them from predators and Large feet to distribute Teeth designed for prey alike body weight and to dig omnivorous diet Teeth designed for meat out water holes eating Have special ankle bones that allow them to climb down trees headfirst © Getting Nerdy, LLC  Who figured all of this stuff out? Charles Darwin, studied the characteristics of organisms in the Galapagos Islands and noticed that they were similar to those on nearby South America. He hypothesized that animals came to the Galapagos from the mainland. The environment determined which animals would survive and which would die off. Those adapted to the new environment survived and became different from their mainland relatives. Example: Iguanas & Finches © Getting Nerdy, LLC  Now you don’t! Now you see me! Traits are inherited and some traits make it easier for living things to survive and reproduce. Camouflage is a trait that makes it very hard to see an animal in its natural habitat. Camouflage is an important part of their survival. It hides the animal from its predators while, at the same time, making the animal a sneaky predator itself. An animal that is best camouflaged in its environment has the best chance to survive, reproduce, and pass its color pattern on. © Getting Nerdy, LLC  Natural Before Selection the Industrial In Action: Revolution, the white “peppered moth” had the largest population The Peppered Moth Therebecause are two they matched phenotypes for athe typelight colored of moth foundbark on in England: the trees. This blackmeant thatspeckled and white birds couldn’t spot them and eat them, so they lived longer. © Getting Nerdy, LLC  When the Industrial Revolution happened, the factories poured out black smoke, covering the white trees with black soot. This caused the white moths to stand out, and the birds ate them sooner than the black ones. The black moth population then grew rapidly because the birds were not naturally selecting them. If this progression were to continue for generations and generations, the gene for the white moths may be completely eliminated from the species. In other words, the birds would cause all of the white moths to go extinct because of evolution. © Getting Nerdy, LLC TYPES of CAMOUFLAGE  Concealing Camouflage: when an animal blends in with its background © Getting Nerdy, LLC © Getting Nerdy, LLC  The light underside of many predatory animals like this ray allow them to blend in with the sun filled waters as they hunt for food below © Getting Nerdy, LLC © Getting Nerdy, LLC © Getting Nerdy, LLC  Disruptive coloration: when an organism’s color is broken up with a pattern like stripes or spots so it confuses or conceals when alone or in a group © Getting Nerdy, LLC  Stripes and spots give the illusion of light and shadow and often confuse prey and predator’s eyes alike © Getting Nerdy, LLC © Getting Nerdy, LLC  Mimicry: when an animal copies or mimics the form of something else © Getting Nerdy, LLC  OWL BUTTERFLY MIMICRY: Eye spots on wings resemble owl eyes. When the butterfly spreads its wings, the eye spots may scare predators. © Getting Nerdy, LLC  CATERPILLAR-SNAKE MIMICRY: These caterpillars have special adaptations that create the illusion of snake eyes or markings so that when predators see them, they are often deterred from eating them because they think they are snakes. © Getting Nerdy, LLC  VICEROY-MONARCH MIMICRY: The Viceroy butterfly has a secret defense. It resembles the distasteful Monarch butterfly which deters animals from eating it, resulting in their survival… © Getting Nerdy, LLC  LEAF MIMICRY: Many insects mimic leaves and other components of nature in order to camouflage themselves from predators and prey… © Getting Nerdy, LLC  FLY-HORNET MIMICRY: We all know that hornets can leave a nasty sting. This fly (pictured upper left) is a mimic of the common yellow jacket hornet (pictured below). Because of this coincidental resemblance, most predators will leave the fly alone, mistaking it for the stinging kind… © Getting Nerdy, LLC  Concealing Coloration: when an animal blends in with its background © Getting Nerdy, LLC  Disruptive coloration: when an organism’s color is broken up with a pattern like stripes or spots so it confuses or conceals when alone or in a group © Getting Nerdy, LLC  Mimicry: when an animal copies or mimics the form of something else © Getting Nerdy, LLC Natural Selection & The Peppered Moth The English Peppered Moth, Biston betularia, flies at night and rests on lichen covered trees during the day. Just like how humans can have red or black hair, the moth comes in two forms of the same species – a pale speckled version which blends in with the light coloured lichen n the trees, and a black, or melanic, version which is easy to see on the light trees. Natural Selection & The Peppered Moth Before the Industrial Revolution, trees were covered in a light coloured lichen and the pale form was easily camouflaged during the day. The melanic form was a dark contrast to the light background so birds easily found them and they were eaten more frequently. As a result, they were less likely to survive and pass their genes on to the next generation which made this form of moth rare within the population. Natural Selection & The Peppered Moth In the late 1700s and early to mid-1800s, the Industrial Revolution created air pollution so thick that it killed the lichens and covered the trees in black soot. As a result, the pale moths stood out against the black background and birds caught them more easily while the melanic form was well-camouflaged allowing them to survive, breed, and pass the dark coloration on to their offspring. Natural Selection & The Peppered Moth The melanic moth became more common among the peppered moths due to selective pressure the birds put on the population due to their inability to find camouflaged forms. In the 1950s, pollution became regulated and as a result, the trees took on their original appearance and lichens again flourished. Natural Selection & The Peppered Moth As a result of reverse selective pressure, the melanic form decreased while the pale form increased in numbers. It is expected that with the current trend, the gene for melanic moths could be completely eliminated from the peppered moth population within the next few years. Natural Selection & The Peppered Moth The peppered moth story provides evidence for changes of frequencies of different forms of a species within a population. However, it does not show large scale evolution.  Now you don’t! Now you see me! So, you think you can make it in the wild? Try your hand at creating Camouflage that will help you survive in various environments with this interactive game … © Getting Nerdy, LLC  Camouflaged Chameleons Objective: To explore and simulate camouflage in animals Here’s what you’ll need to conduct this experiment: Chameleon pattern, colored pencils, markers or crayons What You Do: Day 1 1. Think about the three types of camouflage we discussed and design a chameleon so that it can be camouflaged somewhere in the classroom. 2. Make the chameleon as invisible as possible. © Getting Nerdy, LLC  um… you see that tasty chameleon over Camouflaged Chameleons there or is it just me? Objective: To explore and simulate camouflage in animals …what chameleon? I don’t see anything but a Here’s what you’ll need to white slide… conduct this experiment: Your EYES, a pencil and a piece of paper to tally your kill! What You Do: Day 2 You’re a predatory bird! You will have 10 minutes to quietly stalk your chameleon prey! Afterward, answer the following conclusion …la…la…la… hope nobody sees me… questions from your sheet. © Getting Nerdy, LLC  …nobody’s home… What Happened? The Results and Conclusions: 1. How many chameleons did you see? 2. Which type of camouflage do you think was the best at hiding the chameleon? Why do you think this type of camouflage made it difficult to see the chameleons? 3. Which type of camouflage do you think was least successful at hiding the chameleon? Why? © Getting Nerdy, LLC  So, what does this all mean?... Those chameleons that blended in have the traits that help them to survive. Those that didn’t blend in do not have those traits. Organisms that do not have the necessary traits to survive in the environment will not live as long as those that do have the traits. Therefore, they will not be able to reproduce as much as the organisms that live a long time. More organisms with the desired traits will live from generation to generation. This process is known as natural selection. Remember that natural selection is what drives EVOLUTION! © Getting Nerdy, LLC Natural VS Artificial Selection Environment influences survival Humans influence survival Changes traits in living species from one Happens slowly over time generation to the next Happens quickly over time Selected trait improves chance to Traits are genetically inherited survive and reproduce Trait is desirable to breeders Require diversity or variation of traits Improves an organisms fitness Decreases an organism’s fitness Natural and Survival of the fittest Natural selection is the driving force behind Evolution. Nature essentially decides who lives and who dies based on several factors: a competitive struggle to survive, reproduction and passing favorable traits on to offspring, overproduction of a population which leaves more offspring born than can survive, survival of the fittest, and speciation which is the creation of new species evolving from a common ancestor over time. Natural and Survival of the fittest Survival of the fittest refers to the process of natural selection. It does NOT mean the fittest in terms of strength or size. Instead, it refers to an organism’s ability to survive and reproduce within a particular environment by ways of finding food, obtaining a mate, securing it’s habitat, etc. Individuals who are better adapted to their environmental conditions have a greater chance of passing their successful traits on to the next generation of offspring. Natural and Survival of the fittest Genetic variation and mutation of a species increases their chance of surviving in a changing environment. Those that are not well-adapted to their environment do not reproduce as often or live as long. An organism that survives but cannot reproduce or one that reproduces but does not survive a long time is deemed unfit.