Classification Flashcards
What is classification?
Classification is the process of sorting living things into groups based on how similar they are to each other. It helps us organize and study them better.
How were organisms classified before molecular science and genetics?
Organisms were grouped by their physical appearance, body structure, behavior, and where they lived.
What is taxonomy?
Taxonomy is the science of naming and organizing living things into groups based on their shared features.
What are the 8 hierarchical groups in our classification system?
The groups are: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
Mnemonic: “Do Kings Play Chess On Fine Green Silk.”
Why is the current system called a taxonomic hierarchy?
It’s called a hierarchy because it organizes life into levels, starting with big groups (like Domain) and narrowing down to smaller, more specific ones (like Species).
What is the full classification of a human being?
Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae
Genus: Homo
Species: sapiens
What is a binomial name, and what are the rules for writing it?
A binomial name is a two-part scientific name for a species, like Homo sapiens.
Rules:
• The first word (genus) starts with a capital letter.
• The second word (species) is lowercase.
• Both words are italicized or underlined.
What are the five kingdoms, and how can you recognize them?
Kingdom Key Features
Prokaryotae: Simple, single-celled, no nucleus, cell walls made of peptidoglycan.
Protoctista: Mostly single-celled, some have cell walls, some are plant-like (make food), others eat like animals.
Fungi: Mostly multicellular, cell walls made of chitin, absorb nutrients from dead material (saprotrophic).
Plantae: Multicellular, cell walls made of cellulose, make their own food (photosynthesis).
Animalia: Multicellular, no cell walls, eat other organisms (heterotrophic).
What system did Carl Woese introduce, and why?
Woese introduced the three-domain system: Archaea, Bacteria, and Eukarya. He did this because studying DNA showed that some organisms, like Archaea, were very different from others like Bacteria.
Why do we classify organisms?
- To make studying them easier.
- To understand how they are related.
- To give every organism a unique name that’s used worldwide.
What do we use now to classify organisms?
• Physical traits.
• DNA and genetic information.
• Fossils.
• How embryos develop.
How can DNA and amino acids help classify organisms?
By comparing DNA and amino acid sequences, we can see how similar organisms are. Closely related organisms have similar DNA because they share a common ancestor.
How does the fossil record help with classification?
Fossils show us how organisms looked in the past and how they changed over time. This helps us figure out their relationships and ancestors.
How does embryology help with classification?
When embryos from different animals look similar early on, it shows they likely share a common ancestor. For example, all vertebrates have similar embryos at first.
What is phylogeny?
Phylogeny is the study of how species are related through evolution. It’s like a family tree that shows which species share ancestors.
