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 Taxonomy18th Century

Carolus LinnaeusSwedish Botanist He is known as the Father 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 TaxonomyCharles 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 TheoryWhen 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 SelectionPublished his famous book On the Origin

of Species by Means of Natural Selection4 Main parts to the book

Overproduction of Offspring

Species produce many more offspring than what will survive maturity.

VariationSome 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 SelectionIndividuals with certain variations

compete more successfully than others.

AdaptationsInherited 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.

AdaptionOccurs through variation and natural

selection.Example: Peppered moths in England

during the Industrial Revolution pg 93

CamouflageAllows organisms to blend in with their

environment.Some organisms resemble twigs or leavesOthers resemble non-living things like

stones.Many organisms blend in perfectly with

their surroundings.

Crab Camo Deer Camo Caterpillar Camo

Attract AttentionSome 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

MimicrySome 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.

King Snake

Coral 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.