9D-SPECIATION

Question 1

sSpeciation

Answer 1

the process by which populations genetically diverge until they become different species.

Question 2

species

Answer 2

A species is a group of organisms that can interbreed to produce viable and fertile offspring. Species can also be determined by comparing DNA and amino acid sequences.

Question 3

Why are a horse and a donkey not considered the same species?

Answer 3

A horse and a donkey are not considered the same species because when they interbreed, they produce a mule, which is typically infertile. The inability to produce fertile offspring indicates they are different species.

Question 4

What are mechanisms that prevent species from interbreeding to produce fertile and viable offspring?

Answer 4

Geographical – physical barrier such as oceans and mountains
Ecological – different niches
Temporal – different breeding cycles
Behavioural – courtship behaviour
Structural – differences in reproductive organs

Question 5

Allopatric Speciation

Answer 5

Allopatric speciation occurs when a geographic barrier (such as an ocean or mountain) separates a population, isolating the two groups and preventing them from breeding. This lack of gene flow leads to genetic divergence, eventually resulting in the creation of a new species.

Question 6

What role does a geographic barrier play in allopatric speciation?

Answer 6

A geographic barrier physically separates a population into two or more isolated groups, preventing gene flow between them. Over time, this isolation leads to genetic divergence and the formation of new species.

Question 7

What happens if the two populations that underwent allopatric speciation meet again after being separated by a geographic barrier?

Answer 7

If the two populations meet again after being separated, they may not be able to produce fertile and viable offspring due to the genetic divergence that has occurred. This indicates that they have become distinct species.

Question 8

If two populations that underwent allopatric speciation meet again after being separated by a geographic barrier, will they be able to produce offspring?

Answer 8

If significant genetic divergence has occurred during the separation, they may not be able to produce fertile and viable offspring, indicating they have become distinct species. If they can still interbreed and produce fertile offspring, they may not have diverged enough to be considered separate species.

Question 9

Process of allopatric speciation

Answer 9

1. a geographical barrier separates a population and no gene flow occurs.

Step 2; Different selection pressures act upon each population, favouring different phenotypes

step 3: Eventually, so much genetic variation has accumulated that the two populations can no longer interbreed even if the geographic barrier is removed.

Question 10

What role do the Galapagos Islands play in species diversity, particularly in the case of the Galapagos finches?

Answer 10

The Galapagos Islands, consisting of 19 islands, each represent a specific ecological niche with different selection pressures. The islands are separated by ocean (a geographical barrier), preventing gene flow between populations. This has led to the evolution of 18 different species of Galapagos finches, each with unique beak shapes and sizes adapted to their environment and food source.

Question 11

Types of Galapagos finches and describe

Answer 11

Cactus finch has a thin and elongated break shape, their food soruce is mostly frm cacti as their thin elongated beak allows them to easily pick cactus seeds from the cacti without coming into contact with the spikes

Large ground finch- have thick and short beaks, their priary soruce of food is hard woody nuts and thier thick and short beaks allow them to forcfuelly break open and extract the interior ofthe woody nuts

Medium ground finch-
they have beakers with moderate width and short-their pirmary srouce of food is soft seeds because their moderate and short beaks allow them to only eat soft seeds due to the inabilty to break open harder seeds

Question 12

How do different species of Galápagos finches form through allopatric speciation?

Answer 12

: Different species of Galápagos finches form because, with no gene flow between isolated island populations, each island contains different selection pressures selecting for different phenotype This leads to genetic differences accumulating and the development of new species.

Question 13

Sympatric speciation

Answer 13

ormation of a new species in populations located in the same geographical location.

Question 14

How does sympatric speciation occur through different selection pressures?

Answer 14

Sympatric speciation occurs when a new species forms within the same geographic area, without physical separation. In this process, different selection pressures within the same environment act on various traits (phenotypes) of a population. Over time, individuals with specific traits may diverge from others, eventually leading to reproductive isolation and the formation of a new species.

Additionally, sympatric speciation can result from genetic abnormalities during gamete formation, such as chromosomal mutations, which can create reproductive barriers between individuals within the same population.

Question 15

where does polyploidy occur

Answer 15

Polyploidy occurs when an organisms contains additional sets of chromosomes in its genome.
Seen exclusively in plants

Question 16

Question: How can polyploidy lead to sympatric speciation?

Answer 16

Polyploidy, which occurs when an organism has additional sets of chromosomes, can lead to sympatric speciation. This genetic change, seen primarily in plants, can result in reproductive isolation within the same geographical location, allowing new species to form.

Question 17

examples of polyploidy

Answer 17

Garden onions
Keeled garlic
Chinese chives

Question 18

How is the speciation of Howea palms on Lord Howe Island an example of sympatric speciation?

Answer 18

Answer: The speciation of Howea palms on Lord Howe Island is an example of sympatric speciation because different pH levels in the soil led to the divergence of palm species within the same geographical area.

Question 19

Discus how there is natural selection in peppered moths

Answer 19

There is variations in phenotypes within a population(light and dark coloured moths)

A selection pressure exists(predation from birds) that causes a struggle for survival in some individuals

3. Organisms with favourable phenotype(dark moths in darker environemnt) will be selected for nad have an advantageous phenotype

4.talk about heritabilty

Question 19

How did speciation occur in Howea palms on Lord Howe Island?

Answer 19

Speciation in Howea palms on Lord Howe Island likely happened through sympatric speciation, meaning it occurred without physical separation.

Howea belmoreana lives in neutral and acidic soils, while Howea forsteriana adapted to alkaline soils. This difference in soil types acted as a selection pressure, pushing the populations to adapt differently.

As the population living in alkaline soils adapted, they developed traits like different flowering times, which led to reproductive isolation. This means the two groups could no longer interbreed effectively.

Over time, these differences became significant enough to result in the formation of two distinct species. The fact that this occurred without geographical isolation on the small island supports the idea that it was sympatric speciation.

Question 20

Selective breeding

Answer 20

Process by which humans can select or remove particular traits from a population by directly controlling the breeding of animals or plants

Question 21

Q: What is required in a population for both natural selection and artificial selection to occur?

Answer 21

A: Variation in a population is required for both natural and artificial selection to occur.

Question 22

Q: What are two benefits and disvantages of artificial selection?

Answer 22

A: 1. Improved agricultural crops
2. Domestication of animals

disadvantges is that it can cause mutations and its inhumane.

Question 23

Process of Selective breeding

Answer 23

Determine the desired trait

Interbreed parents who show the desired trait

Select the offspring with the best form or desired trait and interbreed these organisms

Continue process until population reproduces desired trait

Question 24

Selective breeding in shepe

Answer 24

1. variation-sheep population has phenotypic variation. ranging from low to high wool density

2.Selection pressure- as high wool density is favourbale to humans, this trait is selected. Humans act as an artifical selection pressure and estbaolish a breeding population of sheep with high wool density, while indiividulas with low wool density are not permitted to breed.

3.Heritabilty-
As wool density is a heritable trait, the allele frequency of high wool density increases overtimeas only high wool density sheep are allowed to breed, Repeated selection reinforces high wool density expression

Question 25

The effect of selective breeding on genetic diversity

Answer 25

Loss of genetic diversity
Increased inbreeding
which can increase the prevalence of deleterious alleles

Lower adaptive potential – if new selection pressure arises, species may not survive