CHARACTERISTICS AND CLASSIFICATION OF LIVING ORGANISM
Chapter 1
Describe the characteristics of living organisms by
describing:
Movement
Describe the characteristics of living organisms by
describing:
Respiration
Describe the characteristics of living organisms by
describing:
Sensitivity
Describe the characteristics of living organisms by
describing:
Growth
Describe the characteristics of living organisms by
describing:
Reproduction
Describe the characteristics of living organisms by
describing:
Excretion
Describe the characteristics of living organisms by
describing:
Nutrition
MRS. GREN
Nutrition
Movement
Respiration
Excretion
Sensitivity
Reproduction
Growth
Classifications
- Organisms can be categorized into groups
according to their common characteristics.
- This process of classification is known as
Taxonomy.
Taxonomy: it is used to organize and classify living
organisms into different groups based on their
physical, genetic, and behavioral characteristics.
Species
Species: is a group of organisms that can reproduce or
produce fertile offspring .
These species can be grouped based on the features
they share.
The Binomial System
Binomial System: Is an internationally agreed
system in which the scientific name of an organism
is made up of two parts showing the genus and
species.
1- Genus name
2- Species name
Rules to follow in binomial namenculture:
- Genus name always first, species name comes
second.
- Binomial names should always be typed in Italic.
(which indicates they are latin).
- When handwritten each of the names should be
underlined separately.
- Genus name always starts with Uppercase
letters, while all letters in species are lowercase.
EX:
Human:
Homo sapien
Egyptian mongoose:
Herpests ichneumon
Indian mongoose:
Herpests edwardsii
Egyptian mongoose
Indian mongoose
Dichotomous keys
- Keys are used to identify organisms based on a series of questions about their features.
- Dichotomous means “ branching into two” and it leads the user through, to the name of the organism
by giving two descriptions at a time and asking them to choose.
- Each choice leads the user onto another two descriptions.
- In order to successfully navigate a key, you need to pick a single organism to start with and follow the
statements from the beginning until you find the name.
- Then pick another organism and start at the beginning of the key again, repeating until
all organisms are named.
Dichotomous keys
Dichotomous keys
Exercise:
Conical flask
beaker
Measuring cylinder Boiling tube
Round-bottomed flask
To Sum-Up
Characteristics of living organisms
Classifications of organisms
Species
Binomial system
Dichotomous keys
Student Excersize
How classifications systems reflect evolutionary
relationships between organisms?
• Organisms share features because they originally descend from a common ancestor.
Ex: all mammals have bodies covered in hair and feed young from mammary glands.
• Originally, organisms were classified using morphology ( the overall form and shape of
organism, whether is has wings or legs).
• As technology advanced, microscope, knowledge of biochemistry, and eventually DNA
sequencing allowed us to classify organisms using a more scientific approach.
• Studies od DNA sequence of different species show that the more similar the base
sequences in the DNA pf two species, the more closely related those two species are( and
the more recent in time their common ancestor is)
Use of DNA sequencing in classification
However, genetic evidence using DNA provides a different understanding – humans are more
closely related to chimpanzees (1.2% difference in the genome – the complete set of genetic
material of the organism) and gorillas (1.6% different) than to orangutans (3.1% different). Also,
chimpanzees are closer to humans than to gorillas
Any Questions?
see in the next class