Chapter 14 Lesson 2 Classifying Species Classification grouping

Chapter 14 Lesson 2 Classifying Species

Classification • grouping objects or organisms based on similarities

1. Taxonomy – the science of classifying organism s - similarities among organisms indicates that they are somehow related 2. What categories are used to classify organisms? a. Homologies – similar structures or similar biochemistry that results from a common ancestor b. Embryonic development – development of fetus c. Genetics – DNA and gene similarities d. Evolutionary history

History of Classification Systems 1. Aristotle - ~350 BC a. Developed the 1 st widely accepted classification system b. Divided organisms into plants or animals c. Plants were further divided by size and structure (trees, shrubs, herbs) d. Animals were classified by where they lived (land, sea, or

Early Classification • Previous classification system – 2 kingdom: • • Plantae and Animalia Declared inadequate Next system: added – Protista - microorganisms and bacteria – – Fungi – mushrooms, molds, and yeasts

Carolus Linneaus a. Classification system based on physical and structural similarities of organisms b. System called – Binomial nomenclature – two word names i. 1 st part – Genus ii. 2 nd part – Species c. Latin d. Ex. Humans – Homo sapiens e. Scientific names must be in italics or underlined f. Genus name is capitalized, species name is lower case

Scientific Names i. common names can be misleading because they vary (language or location) ii. scientific names are recognized worldwide iii. scientific names indicate relationships – 1. Maple Trees – Genus – Acer 2. Acer rubrum – red maple 3. Acer saccharum – sugar maple

Classification Groups • Taxon – a group of organism (plural – • taxa) Seven Classification Taxa – 1. Kingdom – largest taxa, includes many types of organism with some similarities 2. Phylum 3. Class 4. Order 5. Family 6. Genus 7. Species – smallest category, only includes one type of organism

• Similar species grouped in one Genus • Similar Genus are grouped in one family & so on • Categories – always based on similarities among organisms • Ex. – Phylum Chordata – backbones • Class Mammal – warm-blooded, hair or fur, produce milk for young • Order Carnivore - sharp teeth, claws, hunt and eat meat • As we learn more, the classification of an organism can change • Species – a group of organisms that can mate and produce fertile young

Six Kingdoms Differ in cell structure o Unicellular vs. multicellular o Prokaryotic vs. Eukaryotic - Differ in means of obtaining energy • autotrophic vs. heterotrophic

3. Protista – (protists) a. Eukaryotic b. Single celled (but some, like algae, are multicellular) c. Most are microscopic d. Do not have complex organ systems e. 2 main divisions – 1. Algae – autotrophic a. Plant-like, but do not have leaves or stems b. Important base of many food chains 2. Protozoa– heterotrophic a. Animal-like b. Amoeba, paramecium

4. Fungi a. Eukaryotes b. Unicellular (yeasts) and multicellular (mushrooms and molds) c. Heterotrophic – mainly decomposers d. Cell walls contain – chitin – a long-chain polymer of beta-glucose that forms a hard, semitransparent material e. Absorb food through cell walls f. Develop from spores, do not move

5. Plantea: (Plants) a. Eukaryotic b. Multicellular c. Autotrophic (photosynthetic) d. Cell walls contain cellulose e. Tissues, organs systems f. Do not move around g. Trees, moss, ferns, grass

6. Animalia (animals) a. Eukaryotic b. Multicellular c. Heterotrophic d. Able to move at some time in life e. No cell walls f. Tissues, organ systems Ex. Nervous, circulatory, muscle systems g. Ex. Hydra, sponges, coral, fish, insects, birds, frogs, mammals

Biological Keys • also called dichotomous (2 branched) key • series of paired (2) statements that compare or describe characteristics of organisms in order to identify them • To use a key you always start with the first set of sentences, read the description, compare it to your organism, then follow the instructions to continue the key • You will work to find the name through descriptions until the name of your organism is given

How to make a dichotomous key • divide your samples into 2 groups using one characteristic • write a set of 2 sentences describing the characteristics you have used to divide your object/organisms • Characteristics must be objective (ex. 5 cm) not subjective (ex. Short/long)

Example 1. Has straight sides……………go to 2 Does not have straight sides………. go to 4 2. Has 3 sides ……………………triangle Has more than three sides………………go to 3 3. Has 4 sides ………………………. . Square Has more than 4 sides …………………. . star 4. Diameter is same all over…………. circle Diameter varies………………. oval