classification Flashcards
what is classification
classification is the process of placing LIVING organisms into groups/TAXA based on SIMILARITIES or differences
why do we classify living organisms?
- for our convenience
- to make the study of living things more manageable
- to make it easier to identify organisms
- to help us see the relationships and understand evolution
what were early classification systems based on?
Early classification systems were based only on appearance and anatomy.
were early classification systems accurate?
early classification systems provided enough information to allow accurate classification. but it was easy to make mistakes.
How did Aristotle (384 BC) classify living thing?
in the earliest attempts of classification, Aristotle 384 BC classified all living things as either plants or animals. He further subdivided the animals into 3 groups - those that:
- live and move in water
- live and move on land
- move through the air
Give an example of a mistake Aristotle made with his classification?
His system was based on the similarities that he observed. He noticed that some animals have fins, some have legs and some have wings. unfortunately, this grouped:
fish and turtles
birds with insects
mammals with frogs
How have early classification been updated and made more accurate?
Early classifications have been updated and made more accurate as more research is carried out and more information becomes available.
How do we classify organisms today?
Today there are still many ways of classifying organisms. Taxonomy is a form of classification that focuses on physical similarities between different species, for ease of naming and identification
who was the first scientist to introduce a formal system of taxonomy?
Carl Linnaeus (250 years ago) was the first scientist to introduce a formal system of taxonomy. Linnaean taxonomy is still the basis of the systems we use today
Describe Linnaeus’s classification process?
- Linnaeus studied each organism closely and organised them according to their visible features
- 2 organisms with many similar visible features were grouped closely together
How many organisms did Linnaeus classify?
Linnaeus classified over 70 000 organisms
What are taxonomic groups or taxa?
Linnaeus decided to put his organisms into a series or ranked categories. These categories are known as taxonomic groups or taxa.
How many taxas are in the current system of classification?
there are 8 taxas in the current system of classification
How many taxas were in Linnaeus original classification system?
5 taxas: kingdom/class/order/genus and species. However, as more organisms have been found and described, this original system of classification had to be modified.
Name the 8 taxa:
Domain Kingdom Phylum Class Order Family Genus Species DARING KING PHILIP CAME OVER FOR GREAT SEX
what happens as we go down the taxa?
as we go down through the taxa there becomes increasing similarity between organisms
the number of species in each taxa decreases
classifying humans (homo sapiens) ?
Note: there are no other organisms that today share our genus:
domain: eukaryote: one of the 3 domains of life that consists of eukaryotic organisms that are either single celled or multicellular
kingdom: Animalia: multicellular organisms, cells that have no cell walls
phylum: chordata: animals with backbones
class: mammalia: hairy skins, produce milk to feed their young
order: primates: flat faced, forward facing eyes, opposable digits
family: hominidae: human-like creatures
genus: homo: humans are the only living member of this genus
species: sapiens: all modern humans belong to this species
describe the Linnaeus binomial system?
- the names of the genus and species are written in italics
- Linnaeus devised a system of naming living organisms that uses 2 names
- Linnaeus’s system used latin as the common language, meaning that every scientist will use the same name
What was the problem with the naming system before Linnaeus?
Before Linnaeus, species were identified by a common name, or long and detailed description
this did not work because:
- the same organism may have a completely different common name in different parts of one country/ different countries
- Translation of a language or dialects may give different names
- The same common name may be used for different species in other parts of the world
What does the first part of the name say?
the genus to which the organism belongs
what does the second part of the name say?
the species to which the organisms belongs
How can you identify living organisms?
- A DICHOTOMOUS key is a way of identifying and naming a specimen you have found
- the key provides a series of questions and each question has two answers - usually ‘yes’ or ‘no’
- the answer to each question leads to another question
- Eventually the answers will lead you to the name of the specimen
What was the accepted number for the total number of kingdoms?
for many years 2 (plants and animals) was the accepted number for the number of kingdoms
what is the new accepted number for the total number of kingdoms?
5 - because as more living things were discovered and studied closely, it became clear that not all living things could fit easily into one of these categories
Name the 5 kingdoms?
Plantae Animalia Fungi Prokaryota Protoctista
Describe the main characteristic feature of green plants?
The main characteristic feature of green plants is their ability to manufacture their own sugars from simple molecules by photosynthesis. They are autotrophs - autotrophic nutrition
.
