1.2 The Biological Classification System Flashcards
(18 cards)
What is a species?
A species is a group of organisms that can reproduce to produce fertile offspring.
What is the binomial naming system?
The binomial naming system is a internationally agreed system forclassification.
It gives each organism a scientific name made up of two parts: the genus and the species.
What is the scientific name for humans in the binomial naming system?
Homo sapiens —
Homo is the genus, and sapiens is the species.
The genus name is written first and is capitalized.
The species name is written second and is not capitalized.
The full name is written in italics (or underlined if handwritten).
Example: Homo sapiens or Homo sapiens (if handwritten)
Why do we classify organisms?
Organize and identify them easily
Identify those at risk of extinction
Understand relationships between different organisms
Show how organisms have evolved
Provide a universal system used by scientists around the world
How do we classify organisms?
We classify organisms by studying their:
Morphology – the external features (like shape, size, structure)
Anatomy – the internal structure (like organs and tissues)
These similarities and differences help group organisms into related categories.
Why are DNA and protein sequences used in classification?
Sequences of DNA and amino acids in proteins provide a more accurate way of classification, because they show the genetic similarities and differences between organisms.
How is each species genetically unique?
Each species has a unique number of chromosomes and a unique sequence of bases in its DNA, which makes it different from other species.
For example, humans have 46 chromosomes.
What does similar DNA between organisms tell us about their ancestry?
Organisms with recent common ancestors have DNA that is more similar compared to those with distant ancestors.
This helps scientists understand evolutionary relationships.
What are artificial systems of classification?
A system that groups organisms based on observable features like appearance, size, or behavior, not evolutionary relationships.
What is natural classification?
A system that groups organisms based on evolutionary relationships and genetic similarities (e.g. DNA, common ancestors).
Give one example of artificial classification.
Grouping birds, bats, and insects together because they all fly, even though they aren’t closely related.
What is a key disadvantage of artificial classification?
It can be misleading because it doesn’t show true biological relationships.
What is an advantage of artificial classification?
It is simple and quick to use for identifying organisms based on looks.
Which system is more accurate: artificial or natural classification? Why?
Natural classification, because it reflects evolutionary history and genetic links.
What is the smallest natural group of organisms?
Species
What is dry mass?
the mass of an organism after it has been killed and all water removed from it
What is a common ancestor?
a species that lived in the
past, and is thought to have given rise to several different species alive today; for example, all mammals share a common ancestor
What is genus?
A group of species that share similar features and a common ancestor
