speciation (Evolution)

Question 1

What does speciation mean?

Answer 1

Formation of new pecies from exisiting species (The formation of something that already pre-exisited, however this species is different/”evolved”)

Question 2

What are the mechanism/mode of speciation? and what does it result to?

Answer 2

Happens in 2 ways (/is influenced in two ways)
1) Reproductive isolation
(Cannot breed in under any natural conditions)

Resulting in Different gene pools
(Physically cannot exchange genetic information)
–> Seperate animals and physically cannot reproduce.

Question 3

What is the definition of species? What is the defintion of different speciations?

Answer 3

Species: Indivduals that can interbreed (/reproduce) under natural conditions (without human interferement). the offspring reproduced is VIABLE (sucessful/fertile)

Different species: Species that are unable to reproduce or create viable offspring

Question 4

Does speciation stem from micro or macro evolution? What does microevolution or macroevolution mean?

Answer 4

Stems from both micro and macro evolution, stems from both small scale and large scale changes.
–> Reproducetive isolation techniques focous on microevolution.

microevolution: Changes in gene (allele) frequeincies, which lead to the change in phenotype frequencies. Within a population of species.

Question 5

What is a reproductive isolation mechanism? (General umbrella terms)

Answer 5

Any biological factor that prevents indivduals of different species to reproduce sucessfullly

(Factors may include; behaviour, structure, chemically)

Main categories of reproductive isolation is pre-zygotic (before the formation of the zygote/before the fusion of 2 haploid cells) and post-zygotic (after the formation of the zygote/fusion of the haploid cells)

Question 6

What are the 2 main umbrellas under reproductive isolation and what other category do the posses (do not list out the reproductive mechanism technology)
–> Meanings of each category?

Answer 6

Main categories of reproductive isolation is pre-zygotic (before the formation of the zygote/before the fusion of 2 haploid cells) and post-zygotic (after the formation of the zygote/fusion of the haploid cells)

Within pre-zygotic reproductive mechanisms, you have mechanisms that** prevent mating **and mechanisms (Cannot get inot the situation of mating) that prevent fertilization (Able to mate or want to mate, but the egg cannot be fertilize/the gamates are not fusing).

With post zygotic reproductive mechanisms, the main mechanism/categoy is prevention of hybirds. Where mating was sucessful, and the egg was able to be fertilized, however there is/was no sucess in the actual offspring produce. (Either was unable to grow or unable to reproduce)

Question 7

What categories are under pre-zygotic, prevention of mating. (3)

Answer 7

1) Behavioural isolation
2) Temporal isolation
3) Ecological isolation

Question 8

What categories are under pre-zygotic, prevention of fertilization

Answer 8

1) Mechanical isolation
2) Gamatic isolation

Question 9

What categories fall under post zygotic, prevention of hybrids?

Answer 9

1) Zygote mortaility
2) Hybrid inviability
3) Hybird infertility

Question 10

What is behavioural isolation? Example?

Answer 10

-> Different courtship (ways of matting)
-> Unable to feel attraction towards each other

Ie: Birds have different mating songs, only that certain type of bird is able to recognize that certain type of song.

Question 11

What is temporal isolation? Example?

Answer 11

Mathing seasons are different, different species breed at different times of the year.

-> Most evident within flowers
Example: Flowers bloom and breed at different times of the year, if a flower isnt blooming it cannot physically mate (cannot exchange pollen(

Question 12

What is ecological isolation? Example?

Answer 12

Species live in different habitats of the same region, therefore rarely encounter each other.
-> SAME ENVIRONMENT
-> DIFFERENT HABITAT
–> example: Birds live in the air/trees, fish live in the lake. (Same habitat)

Question 13

What is mechanical isolation? Example?

Answer 13

Anatomy incompatiablility, the organisms cannot physically mate.
–> Most animals operate a lock and key system (Only a certain key fits in a house, therefore only a certain genital can fit in a certain organism/species)
–> More species have uniquely shaped female and male genitilla.

Question 14

What is gamatic isolation? Example?

Answer 14

Gamates are present and produced within the same environment however do not recognize each other.
–> Male gamates are unable to recognize and fertilize the egg, due to the lack of chemical attraction and recognition

Example: Marine animals release sperm or eggs into open water, and is only reognized by these other specific marine animals

Question 15

What is zygotic mortaility? Example?

Answer 15

Organism is formed/fertilization and mating was sucessful, but the organism is unable to devolpe, and dies in a very very short peropd of time
-> Happens very early on, where the organism does not even produce an embryo (one of the possibilities) (However, usually is never birthed out)
–> Zygote are not viable

Question 16

What is hybrid inviability? (Example?)

Answer 16

A hybird is sucessful, therefore fertilization and mating occured sucessfully, however the hybrid dies before birth or shortly after birth
–> Significantly more devolped than hybrid inmortaility.
–> Often ends up being misscarried or becoming a stillborn offspring.

Question 17

What is hybrid infertility? Example?

Answer 17

A healthty, livabile, viable, off spring is produced but cannot reproduce (it is sterile)

–> bECAUSE OF ITS INABILITY TO REPRODUCE, IT IS NOT A DIFFERENT SPECIES, to create this offspring you need to continiously breed the 2 different organisms, which does not align with the category “Different species or species”

–> Example:
Male donkey + Female horse = Mule.

Question 18

All isolation techniques prevent ____, there fore for speciation to occur organismsm must be ____.

Answer 18

1) Gene flow
2) Gentically isolated

Question 19

What is allopatric speciation?

Answer 19

The geograhic seperation of a species, where a single species is seperated into 2 geographically isolated populations (therefore exposed to different selective pressues, allowing them to evolve seperately)

–> Can occur as like a sudden natural disaster (a formation of a remive beside the 2 species), human interference with the habitat (cutting trees down, etc), or migration/oraganisms choose to move to a new habitat.

Question 20

How does allopatric speciation help organismsm evolve seperately?

Answer 20

1) Natural selection
(Different environments = different selective pressures = different organisms will be favoured = difference in what is “common” or what allele is common, and overtime, enouch different adaptations and changes will occur that the organisms will be considered as different)

2) Mutations
(Any random mutations that happen in one population cannot be shared to the other because they physically cant breed together. therefore introduction of new genetic information can be widespread in one population and not the other, defficiating the two)

3) Geneflow
(Cannot mix and interbreed, therefore slowly losing the genetic similiarties/relatability)

Question 21

What is sympatric speciation?

Answer 21

Organisms are within the same environment, and can acess each other, but are geneticall seperated.
–> Can be sudden or gradual, but usually happens by chance (usually involves a mutation)

Question 22

How does sympatric speciation work?

Answer 22

Mutations can make indivduals unable to reproduce with each other in the population, which can result in…
(The indivdual being able to reproduce w/o a partner)
OR
(If the mutation is shared among a small ground of people, people who have this mutation can reproduce with each other, but not with the original population)
–> Results in a reproductive isolated population, because they are not interbreeding with each other, therefore they have the potiental to form a new species with time.

Question 23

How does sympatric speciation create polypoids? (What are they and how are the defined as a different species)

Answer 23

Polypoids = organisms with more than 2+ homologous pairs of choromosomes, and is usually a mutation.
-> Genetically seperated indivduals from the original population

–> Happens because of non-disjunction (Trisomy or monosomy)
–> Polypoids usually produce fertile offspring when mated with each other, but sterile offspring when mated with the original population/species
(By defiintion they are reproductivily isolates, because they cant mate and have different genetic makeups)

Question 24

How does human interactions induce or influence speciation?

Answer 24

Allopatric speciation can be induced by civilization, while geneflow can be artifically mainted within a species by conservational practices (the idea of conserving an organism, ie zoos/breeding centers)