Classification

Traditionally, the morphology (_________) of the organism was the basis for its classification. Modern taxonomy now takes into account other types of evidence when attempting to classify an organism.

(structure)

He divided animals into three groups

1 Land dwellers 2 Air dwellers 3 Water dwellers

Darwin's Theory of Evolution

1. Organisms produce more offspring than can survive. Of the offspring that do survive, many will never reproduce 2. Because more organisms are produced than can survive, there is: intense competition for limited resources, such as food, water, and shelter 3. Individuals that are best suited to their environment survive, reproduce, and pass their traits on to their offspring. Other organisms that are less suited for their environment often die, or will not be reproductively competitive. This is the process of "natural selection" and causes the many species of organisms on Earth to change over time. facts: The species that are alive on Earth today are descended with modification from ancestral species that lived in the past. Natural selection has led to a staggering diversity in organisms. To study this diversity, scientists must give each organism a name and sort them into groups. *more offspring than can survive leads to competition for resources, the best suited survive and pass on traits to offspring.

Scientists have described and named a total of ______ species

1.5 million

It is estimated that the total number of species is about

10 million

Organisms were first classified more than _____ years ago by the Greek philosopher, ________.

200, Aristotle

A change to the 5 and 6-kingdom systems is the evidence that all living things seem to fall naturally into ____________________. In recent years, this led to the establishment of a: 3-domain system. Domains are essentially: super kingdoms, a taxonomic level even higher than the kingdom level.

3 broad groups

Each subset was further subdivided until he had developed ________ levels of classification.

7

Cladogram

A diagram that shows the evolutionary relationships among a group of organisms.

Vestigial Structures

A structure that is reduced in size and seems to be "left over" from a previous ancestor. Examples: Human Appendix "Hips" in snakes. *think vestigial veggies no-one eats their veggies on their plate

Kingdoms and Domains

As new discoveries have been made, the systems of classification had to be changed. The first attempt at scientific classification was Linnaeus with his _________2- kingdom______ system. Since the time of Linnaeus, many changes have been made in the ways that scientists classify organisms.

Mating occurs, but the offspring do not survive.

Bullfrog eggs may be fertilized by the sperm of the leopard frog. The eggs develop to a point, but do not survive. There is too much difference in the chromosomes.

Problems with original classification groups

By the 15th and 16th centuries, it became obvious that there were many problems with this system of classification. Many organisms were placed in groups to which they had no real relationship with the other members of the group. The use of common names was very confusing. For example: catfish, jellyfish, shellfish. Many new organisms were being discovered and needed to be classified.

In response to the need for a better system of classification, the Swedish naturalist, _______________, developed the system of classification that we still use today.

Carolus Linnaeus

Cladistics

Cladistics is a relatively new method of: classifying organisms.

The offspring may survive but they are not fertile EX:

Example: horse + donkey = mule

All scientific names are in _____. It is understood by all scientists.

Latin

Geographical Barriers

Many organisms simply do not come into contact with one another.

Behavioral Barriers

Many organisms, especially in the animal kingdom, will not mate unless certain behaviors are exhibited.

Barriers between the species: What factors keep the species apart? Physical Characteristics

Mating is impossible under natural conditions for many organisms. Ex: can't mate a mouse and elephant

Morphology definition

Morphology is classification based on: the structures possessed by the organism. *The average person would use color and size, but these are the least important in classification. *This was the basis for Linnaeus' system of classification.

facts abt divisions:

Organisms are placed in the same species if: they can mate and produce fertile offspring. A species contains: only one type of organism. In the system developed by Linnaeus, the ____kingdom____ was the biggest, broadest group. More recently scientists have added an additional level above the kingdom called a "__domian____".

Analogous Structures

Similar in function but not in structure. Analogous structures are not derived from a common ancestor. Example: The wing of a bird and the wing of a butterfly have the same function, but there is nothing in common in their structure.

Taxonomy

The branch of biology that classifies organisms and assigns each organism a universally accepted name.

Binomial Nomenclature definition

The system of assigning a scientific name that consists of two parts.

If two species acquire the same characteristic from separate evolutionary processes- are those characters homologous or analogous?

They are analogous.

This genetic similarity is an indication that yeasts and humans share _____________________.

a common ancestry

derived character

a feature that evolved only within the group under consideration

Evolutionary Relationships Fossils show that organisms ______ today are similar to organisms that are now ________.

alive, extinct

Genetic Similarities Two organisms that bear no resemblance to one another_______ may still be related to one another. Two different "looking" organisms may have similar ___ in their DNA.

anatomically genes

He developed a naming system called ___________________ that is still in use today

binomial nomenclature

Cellular Organization Similarity in ______________ provides evidence that organisms may be related.

cell structures Examples:plastid cell thingies

Similarities of ____________________ found within cells can be used as evidence to show relationships between organisms.

chemical compounds

Similarities in ____________________________ provide evidence of phylogenetic relationships.

embryological development

Some organisms show no similarities as adults, but are very, very similar as __________.

embryos

An example might be the _________ of birds. Birds are the only animals to have feathers. It is therefore assumed that feathers evolved within the bird group and were not __________ from a distant ancestor. Shared derived characters are strong evidence of ___________________ between the organisms that share them.

feathers inherited common ancestry

The _______ name is always capitalized; the ________ name is never capitalized.

genus, species The two names are always written: in italics or underlined. No two organisms can have the same name.

Linnaeus developed a system that placed an organism in a particular _______ and assigned it a _______________.

group, scientific name

Aristotle first sorted organisms into two groups

plants and animals

Cladistics uses features called "________" to establish _______ relationships.

shared derived characters evolutionary

Linnaeus set up a classification system based on____________________. He thought that the organisms that looked alike were: the most closely related.

structural similarity

Rules of Binomial Nomenclature (Linnaeus) The scientific name always consists of two words ______ and _______

the genus and the species.

Convergent Evolution

two unrelated animals that occupy the same ecological role in their ecosystems will tend to converge on similar solutions. They look identical but are unrelated.

Homologous structures

have the same structure, but different functions. Example: The bones found in the wing of a bird, the wing of a bat, the forearm of a human and the flipper of a whale are homologous to one another. Fins of sharks and dolphin are not homologous. The greater the number of homologous structures two organisms share, the more: closely related they are thought to be.

He first divided all organisms into large groups that he called ___________. He based his classification on two kingdoms:

kingdoms, plant and animal

A comparison between the proteins of two organisms serves as a "_________________". Simple __________ occur all the time, causing slight differences in the DNA and the proteins being built. When the proteins of two different organisms are compared, the _______________________ in amino acid sequences is a clue as to how long ago two species diverged from a shared common ancestor.

molecular clock mutations DNA proteins number of differences

Archaeopteryx(the wild bird dino chicken) The fossil record gives us many clues as to the ____________ of ancient species, but it is an ____________ record. Other lines of evidence must be considered when classifying an organism. Following are 5 additional areas of consideration.

morphology, incomplete

convergent evolution

not cuz loo same they just happen to look the same

Do the two organisms being compared have the same ________ of chromosomes? The same ______ of chromosomes?

number type Example: Humans have a gene that is the code for building a protein called myosin. This protein is a primary component of our muscles. Yeasts (which have no muscles) have the same gene. The gene in yeasts produces the same myosin protein as it does in humans. In yeasts, this protein is used to materials around the inside of the cell.

Each subdivision of a kingdom is called a _______ in the animal kingdom, or a _______ in the plant kingdom. A kingdom would be further subdivided into smaller groups.

phylum, division