Taxonomy

When did scientists begin classifying living things? Taxonomy: The system of classification which divides living things into groups of shared characteristics based on their physical appearance.

Early Taxonomy 18th Century Carolus Linnaeus Swedish Botanist He is known as the Founder of Taxonomy First broke living things into Animals and Plants Work was widely accepted by the early 19th century and is still used today.

Early Taxonomy vs. Modern Taxonomy Linnaeus first classified organisms by their shared characteristics (observable traits). Modern taxonomists classify organisms on both shared characteristics and evolutionary relationships.

Early Taxonomy Charles Darwin Visited the Galapagos Islands near South America in the 1830’s. He observed finches and speciation on the Galapagos Islands. He was the naturalist on the HMS Beagle Collected plants and animals that he found when the ship stopped. Also collected fossils. 5 year voyage

Darwin's Theory When he returned home, he studied his collections and tried to figure out how organisms could change over the years. He said that only the organisms that are best suited to their environment survive, passing their traits on to their offspring. This is known as Natural Selection Published his famous book On the Origin of Species by Means of Natural Selection 4 Main parts to the book

Overproduction of Offspring Species produce many more offspring than what will survive maturity.

Variation Some species are not exactly alike in all of their traits. Some traits increase the chances that the individual will survive and reproduce. Other traits decrease the chances of survival. These variations are genetic and can be inherited.

Struggle for Existance All organisms must compete for food, water, and living space. In addition many individuals are killed by other organisms. Only some of the individuals in a population survive adulthood.

Successful Reproduction Successful reproduction is the key to natural selection. The individuals that are well-adapted to their environment are more likely to survive and reproduce.

Natural Selection Individuals with certain variations compete more successfully than others.

Adaptations Inherited features that help increase an organisms chances of surviving and reproducing. There are adaptations for obtaining food, protection, and for locomotion. Obtainment of food Venus’ flytrap’s leaves (catch insects), Spiders glands that secrete silk (build web to catch insects), and Hummingbirds long, thin bill (reaches nectar in flowers). Protection  Cactus’s sharp spines that protect it from being eaten Locomotion Mosquito’s wings enable it to fly, humans’ legs let us walk.

Adaption Occurs through variation and natural selection. Example: Peppered moths in England during the Industrial Revolution pg 93

Camouflage Allows organisms to blend in with their environment. Some organisms resemble twigs or leaves Others resemble non-living things like stones. Many organisms blend in perfectly with their surroundings. Caterpillar Camo Crab Camo Deer Camo

Attract Attention Some organisms have developed adaptations to attract attention. Some do this to attract members of their own kind for mating purposes Example: Male Peacock and Male cardinal Others do this to warn enemies of their bitter or smelly secretions. Example: Skunk, Wasp, Lionfish, Monarch butterfly

Mimicry Some animals act like or look like another animal that is dangerous in order to protect themselves from danger. Examples: The king snake looks like the coral snake. The coral snake is poisonous but the King snake is not. One type of moth mimics wasps. Another form of mimicry is found on insects that have large spots that resemble eyes on their bodies. Many birds are frightened by these eyespots and so will avoid eating these insects.

Coral Snake King Snake

Adaptations for Seed Dispersal Most plants produce seeds that grow into new plants. Seeds cannot always survive if they simply drop and grow beneath the adult plant so it is necessary that they be adapted for dispersal.

Natural Selection in Action Insecticide Resistance Insecticides that used to work well are not as effective because insects have adapted. Adaptation to pollution In the 1850s the pale peppered moth was common and the dark peppered moth was rare. Now due to pollution (darker air) the dark moth is much more common because it blends in easier to its environment.