Taxonomy and evolution Flashcards
- Classification, taxonomy and phylogeny - Evolution of domestic animals - Case study – the horse
What is a classification?
Process of sorting living things into groups
What is taxonomy?
The study of principles and classification
What is a species?
The basic unit of classification; a population or group of populations whose members can interbreed and produce viable, fertile offspring
How are species named?
Using a binomial naming system with Latin names for genus and species
What are the formatting rules for binomial nomenclature?
The genus starts with a capital letter; if handwritten, both genus and species names are underlined; if typed, they should be in italics
Give an example of a binomial name
Bos taurus - where Bos is the genus and taurus is the species
What are the characteristics of the genus Equus?
- Molarisation of premolars
- hypsodont teeth,
- unguligrade walking
- odd number of digits (just one)
- third trochanter of femur
- talus doubly keeled
- limb elongation
What is hypsodont dentition?
Teeth that grow throughout life, common in grazing animals like horses
What is unguligrade locomotion?
Walking on the nail/hoof
What is the evolutionary significance of horses?
The horse’s evolution provides evidence of species development through fossils and genetic markers, with changes in size, teeth, and foot structure
What was the first known ancestor of the modern horse?
Hyracotherium (Eohippus) from the Early Eocene
What were the key traits of Hyracotherium?
- Size of a small dog
- 4 toes on the front, 3 on the hind
- Orbit not fully formed
- 44 brachydont teeth (primitive dentition)
- Flexible back
- Separate distal limb bones (tibia/fibula, radius/ulna)
What evolutionary changes occurred in Mesohippus and Miohippus (Late Eocene to Late Oligocene)?
- Size of a large dog
- Lengthened legs and feet
- 3 toes front and hind
- Orbit still not fully formed
- First premolars vestigial
- Straightened and stiffened back
What were the key evolutionary changes in Parahippus and Merychippus (Miocene period)?
- Size of a small pony
- Reduction of lateral toes
- Hypsodont teeth, deepened lower jaw
- Formation of orbit (zygomatic arch)
- Fused and elongated lower leg bones
- Increased head size
- Formation of sinuses
