Defining a Species + Classifying and naming life

what is a species? 

a group of similar organisms whose members can interbreed with eachother 

what are two different species called when they cant produce fertile offspring?

reproductively isolated 

what keeps a species apart?

behaviours, mating seasons, sex organ structure, genetic arrangements 

what is a hybrid?

the offspring of two closely related but different species. e.g. a horse and a donkey creates a hybrid mule
hybrids are usually viable but sterile, so the parents are still seperate species

what are the limitations of biological species concept? 

fossils and extinct organisms, asexual reproduction, geographical barrier, physical size

what is apomixis 

a form of asexual reproduction where an embryo develops without fertilisation (an animal with apomixis is called parthogenesis)

ring species definition 

a connected series of neighbouring populations, spread around a geographical barrier. 

> where each group can mate with the groups next to it, but the two end groups have changed so much that they can no longer interbreed where they meet

varieties definition 

differ in appearances, not geographically isolated and can interbreed freely like breeds of cats.

classifcation 

arranging things into groups according to their observed similarities 

hierarchical classification 

grouping form large, genera groups to smaller, more specific groups 

taxonomy 

the act of naming and classifying organisms based on physical and biochemical characteristics 

list the taxonomic hierachy from most general to specific 

domain, kingdom, phylum, class, order, family, genus, species 

mnemonic: Dear King Phillip Came Over For Good Soup

Domain

The highest and broadest level. splits life into three massive groups depending on basic celullar structure (archea, bacteria, eurkarya)

Kingdom

divides the domains into smaller groups based on how they get food (animals, plants, fungi)

Phylum

group organisms with a shared basic body part

Class

narrows the phylum down further

Order

group families with similar diets or major physical traits

Family

a collection of closely related genera

genus

a small group of species that look very similar and are closely related

species

most specific.