Species Definitions

Question 1

In 1973, a single small population (< 250 plants) of Stephanomeira malheurensis was found among a much larger population (> 25,000 plants) of S. exigua in Harney Co., Oregon. Both species are diploid and have the same number of chromosomes (N = 8). S. malheurensis can self-pollinate, but S. exigua cannot. Though the two species look very similar, there are 5 documented morphological differences as well as several genetic differences. F1 hybrids between the species produce 50% fewer seeds and 76% less pollen than within species crosses. F2 hybrids showed various developmental abnormalities.

For each species concept state if the concept would identify the two types of plants as the same or different species. Use specific information from the passage to justify each statement.

Mention all four concepts (ecological, phylogenetic, morphological, and biological)

Answer 1

1- By the ecological species concept, they are considered the same species since they were found together, meaning that they share a niche

2- By the Phylogenetic species concept, they are different species since it is stated that they have several genetic differences

3- By the phenetic concept, they could be either since they look similar but there are 5 undocumented morphological differences

4- By the biological concept they are different since they produce abnormal offspring

Question 2

Maggot flies tend to mate with their own kind.

Hawthorn maggot flies strongly prefer to mate on and lay fertilized eggs in hawthorn fruit. Apple maggot flies strongly prefer to mate on and lay fertilized eggs in apple fruit.

There is only a 4-6% hybridization rate between hawthorn and apple maggot flies.

By the morphological species concept, is there enough information to state if maggot and hawthorn flies are the same species? If so, are they?

Answer 2

Not enough information.

Question 3

Maggot flies tend to mate with their own kind.

Hawthorn maggot flies strongly prefer to mate on and lay fertilized eggs in hawthorn fruit. Apple maggot flies strongly prefer to mate on and lay fertilized eggs in apple fruit.

There is only a 4-6% hybridization rate between hawthorn and apple maggot flies.

By the biological species concept, is there enough information to state if maggot and hawthorn flies are the same species? If so, are they?

Answer 3

Not enough information. We know that they can produce offspring but we do not know if they are sterile or fertile.

Question 4

Maggot flies tend to mate with their own kind.

Hawthorn maggot flies strongly prefer to mate on and lay fertilized eggs in hawthorn fruit. Apple maggot flies strongly prefer to mate on and lay fertilized eggs in apple fruit.

There is only a 4-6% hybridization rate between hawthorn and apple maggot flies.

By the ecological species concept, is there enough information to state if maggot and hawthorn flies are the same species? If so, are they?

Answer 4

Yes, they are different species

Question 5

Maggot flies tend to mate with their own kind.

Hawthorn maggot flies strongly prefer to mate on and lay fertilized eggs in hawthorn fruit. Apple maggot flies strongly prefer to mate on and lay fertilized eggs in apple fruit.

Hawthorn and apple maggot flies are genetically distinguishable and have distinct genetic profiles.

There is only a 4-6% hybridization rate between hawthorn and apple maggot flies.

By the phylogenetic species concept, is there enough information to state if maggot and hawthorn flies are the same species? If so, are they?

Answer 5

Yes, they are different species

Question 6

Are unequal gamete sizes relevant for explaining adult behavior?

Answer 6

Yes. Typically, there are insufficient eggs to go around; males end up having to compete for access to them