Chapter 17: Speciation Flashcards
Lineage
Is a series of ancestors and descendant population
Speciation
is the process by which new species form. It occurs when groups in a species become reproductively isolated and diverge
Species Concept
How biologists define a species form
How many ways are there to define species?
There are 27 ways
Who is Carl Linnaeus?
He is the father of modern taxonomy
Binomial Nomenclature
is the formal naming system for living things that all scientists use. It includes Genus + species
Biological species concept
organisms belong to the same species if they can interbreed to produce viable, fertile offspring
What are the limits of the biological species concept?
doesn’t include asexual reproduction
Can’t breed with other groups
Ignores the fact of hybridization
Morphological Species Concept
Where a group of individuals looks the same
allopatric speciation
When physical barriers pop up between an ancestral species and make the species evolve into separate species
sympatric speciation
groups from the same ancestral population evolve into separate species without any geographical separation
What are the limits of the morphological species concept?
doesn’t take account of genes
doesn’t accept the same species if they look different
Operational Definition
A checklist of things in order to make something true
Species
Groups of organisms that mate with one another
What is the most important factor in the long-term isolation of sexually reproducing lineages from one another is what?
It is the evolution of reproductive isolation
Reproductive Isolation
A state in which two groups of organisms can no longer exchange genes
What is the Dobzhansky-Muller model?
It describes how reproductive isolation between two descendant lineages can develop through the accumulation of incompatible genes/chromosomal arrangements
Reproductive isolation does what?
It increases with an increasing genetic divergence between populations
Polyploidy
Duplication of sets of chromosomes within individuals
Autopolyploidy
Duplication of sets of chromosomes within the same species
Allopolyploidy
Combines the chromosomes of 2 different species
What animals can form polyploid reproduction?
Some types of fish: salmon and trout
What are the two mechanisms to prevent hybrids?
Prezygotic and postzygotic isolating mechanisms
Prezygotic Isolation Mechanism
It prevents hybridization through three different forms
Postzygotic Isolation Mechanism
Prevents hybrid offspring from surviving and reduce reproduction rates through three different mechanisms
What are the three different ways to prevent hybridization?
- Mechanical Isolation
- Temporal Isolation
- Behavioral Isolation
What is Mechanical Isolation?
is a form of reproductive isolation that prevents two different species from interbreeding with one another (hyenas)
What is Temporal Isolation?
is when species that could interbreed do not because the different species breed at different times
What is Behavioral Isolation?
Where individuals may reject/fail to recognize individuals of other species as potential mating partners
What are the three methods to prevent hybrid offspring from surviving and reproducing?
- Low hybrid zygote viability
- low hybrid adult viability
- Hybrid infertility
What is low hybrid zygote viability?
refers to a lower potential to survive for organisms whose parents have incompatible genetics
What is low hybrid adult viability?
Prevents hybrids from maturing into reproductive adults because the hybrids will die before sexual maturity
What is hybrid infertility
hybrid offsprings that develop normally and reach sexual maturity, however, they’re sterile
