3.1.2 - What is a species? Flashcards
definition of a species.
A group of organisms that can interbreed to produce fertile offspring.
definition of a breed.
a group of animals of the same species that have different characteristics that make them different to other members of that species.
definition of variety.
a group of plants of the same species that have different characteristics that make them different to other members of that species.
One reason why species need to be identified?
To measure biodersity
What is the morphological species concept?
Looking at the inside and outside characteristics of an organism to classify it
Limitations of the morphological species concept?
Appearance can be affected by many things such as environment.
What is the reproductive or biological species concept?
Classified due to reproductive behaviour
overcomes sexual dismorphisms - differences in male and females
Limitations of the biological species concept
Not all organisms of the same species live in the same area to reproduce
What is the ecological species concept?
Based on ecological niche occupied by an organism
What is the mate- recognition species model?
Based on unique fertilisation systems including mating behaviour
Limitations of the mate - recognition species model?
Many species will mate with other species and may even produce fertile offspring.
What is the genetic species model based on?
Based on DNA evidence
Limitations of the genetic species model?
People still have to decide how much genetic difference makes 2 organisms members of the same species.
What is the evolutionary species model?
Based on evolutionary relationships between species, members of the same species are evolving together
What are some limitations of species models?
- Finding the evidence - many living things have never been observed mating for example
- plants of closely related species interbreed and produce fertile hybrids which may lead to confusiom.
