Evolution by speciation

Question 1

Species

Answer 1

Groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups and produce viable offspring that are fertile

Question 2

Speciation

Answer 2

Process by which a new species evolves

Question 3

New species arise as a result of…

Answer 3

Reproductive isolation and the lack of gene flow which causes Gentic changes in the gene pool and as a result members are no longer able to interebreed with the members of the same species

Question 4

Allopatric speciation

Answer 4

Occurs when 2 populations are geographically separated form each other as a reuslt there are no gene flow and no migration
- natural slection may play out differently in the 2 septicemia now that their gene pools are separated
EX: founder effect

Question 5

Sympatric speciation

Answer 5

New species arise without a geographic barrier
- occurs without a geographic separation
- reasons= ecological and chromosomal aberrations)

Question 6

Ecological isolation

Answer 6

Occurs in populations that gain preferences within the local habitat and seperate form each other an gravitate twoards those preferences
Ex: Hawthorn flies

Question 7

Chromosomal aberrations

Answer 7

Changes in the # of chromosomes can imdediatealy cause reproductive isolation
- polyploidy= mistakes during meiosis that develops an offspring that has 2X so much chromosomes as the parents (more likely to happen in plants)
Can reproduce with other polyploidy’s

Question 8

Covevolution

Answer 8

As one species changes the other species must also change in order to adapt

Question 9

Symbiotic relationships

Answer 9

Species tend to evolve together and both benefit

Question 10

Endosymbiotic theory

Answer 10

The mitochondria and chroloplast evolve with eukaryotic cells and have their own dna sequences which is different form the nucleus and the mitochondria and the host cell evolve together

Question 11

Adaptive radiation

Answer 11

One species gives rise to many species in a realatively short period of time and as a result exploits the reasources and spreads out to fill the large area with their size (Darwin’s finches)

Question 12

Isolating mechanisms

Answer 12

The structural and behavioral modifications that prevent interbreeding and maintains the species reproductive isolation
- consists of prezygotic and postzygotic mechanisms

Question 13

Prezygotic mechanisms

Answer 13

Any structure , psychological function, or behavior that prevented organisms of 2 populations form mating
- includes geographical, temporarl, behavioral, and mechanical isolation

Question 14

Geographical/ habitat isolation

Answer 14

2 species preferences on their habitat keeps them away from each other and maintains reproductive isolation
- ex: water and land snakes

Question 15

Temporal isolation

Answer 15

When members of a species breed at different times which isolates them from each other and they can’t interbreed and share their gentic information
EX: winter v/s summer breeding season

Question 16

Behavioral isolation

Answer 16

Members of the same species behave differently with their mating practices
-these behaviors prevents a female from chosing 1 differnt male form the same species over the other

Question 17

Mechanical isolation

Answer 17

Some members can’t mate with other members because the reproductive parts are not able to fit

Question 18

Gametic isolation

Answer 18

Occurs in aquatic animals
Red and purple sea urchin can’t fertilize an offspring because their gametes are incompatiable because there are protiens and chemicals an the surface of the gametes that prevent successful fertilization between the 2 gametes
- sperm and eggs can not fuse

Question 19

Postzygotic barriers

Answer 19

Any structure, physiological or developmental abnormality that prevents organisms of 2 populations, once mating has occurred form producing vigorous fertile offspring

Question 20

Reduce hybrid viability

Answer 20

The hybrids are no viable and have shorter life spans and the babies can’t reproduce so the lines ends with them and the 2 parents are still 2 different species

Question 21

Reduce hybrid fertility

Answer 21

The hybrids can live long and healthy lives but are sterile and can’t reproduce

Question 22

Extinction

Answer 22

The death of all members of a species/ the ultimate fate and 99.9% of species goes through it
- caused by intro of new predators, completion among species, and habitat destruction
- also caused by over speciation