Year 13 Biology

Species RelationshipsCan be;

1. Positive (Co- operative)2. Harmful (Exploitative)

Co operative relationships between Species

• Co operative relationships– 1. Mutualism: Co-evolution• Both species benefit

– 2. Commensalism• One species benefits, the other is neither harmed nor

benefits

Exploitative relationships between species

• Exploitation between species– 1. Predation

• Predator/ prey• Short term can effect each others population numbers• Long term can shape evolution patterns

– Example: The Lion and the Gazelle

– 2. Parasites• Depend on their host for food• Weaken but usually don’t kill the host• Ectoparasites (external) and endoparasites (inside)

– Example: :Lungworm (endo) or Fleas, Mosquitos and Lice (ecto)

– 3. Grazing• Grazers consume part of many organisms, which are not killed

– Example: Sheep, cattle, deer

Year 13 Biology

Practice Exam Questions 3.5 Patterns of Evolution

Question 1:

• The animal group that includes reptiles and frogs is called herpetofauna. New Zealand has many endemic species within this group including; the tuatara, geckos and skinks, and four species of native frog. The picture shows the Native Hochstetters Frog which only exists in New Zealand. This frog species is widely distributed in at least 10 fragmented and isolated populations in the northern half of the North Island. They are nocturnal and shelter by day in wet crevices or under stones or logs close to the water’s edge in shaded streams.

• In relation to the herpetofauna group that exists in New Zealand, identify the type of speciation demonstrated.

M

Question 2

• Discuss how the diversity of an endemic species has come to exist in New Zealand today in relation to geographical events and selection pressures.

Chevron Skink

E

Question 3• The Australian Broadheaded Snake feeds primarily on velvet geckos. Downes and

Shine (1998) demonstrated that velvet gecko populations that are sympatric with this snake species have evolved the ability to detect and react to the scent of this predator. Their experiments showed that the geckos are significantly less likely to enter rock crevices if the scent of the snake was distributed in the area. In turn, the snake has evolved to remain sedentary for extended periods of time, which minimises the extent to which its scent is spread over the rocks. Furthermore, they showed that while specimens from populations of geckos that are sympatric with the snake predator react to the scent, those that came from allopatric populations did not. Additionally, the geckos did not respond in the same manner to other snake species that do not prey on geckos

• Explain the relationship which exists between the Broadheaded Snake and Velvet Geokos

• Identify some issues which could arise if the Velvet Gecko species was eradicated

E

Question 4

• Most fish populations, in New Zealand and around the world, are intensively harvested by fishermen. The mesh sizes used in their nets means that the fish which are trapped are most likely the older and larger individuals in the species

• Explain how this selection pressure could lead to an alteration in the population if fishing practices continue

M

Question 5 (a)

• A group of Hawaiian Laupala crickets have a very rapid rate of speciation.

• Female Laupala crickets detect tiny differences in the pulse rates of male courtship songs, which differ between species. They will not mate with males of another species.

• Closely-related species of Laupala that live on one island have no clear physical differences, they have similar diets and possess no physiological differences that would prevent them from interbreeding.

• (a) Describe whether the type of speciation is occurring between these closely-related Laupala crickets is sympatric or allopatric. Give a clear reason for your choice.

• (2009)

Question 5 (b)

• A group of Hawaiian Laupala crickets have a very rapid rate of speciation.

• Female Laupala crickets detect tiny differences in the pulse rates of male courtship songs, which differ between species. They will not

mate with males of another species.• Closely-related species of Laupala that live on one island have no

clear physical differences, they have similar diets and possess no physiological differences that would prevent them from

interbreeding.

• (b) Use the definition of a species to justify the decision by scientists to define crickets with different songs as different species, despite

their very similar characteristics.• 2009

Question 5 (c)

• A group of Hawaiian Laupala crickets have a very rapid rate of speciation.

• Female Laupala crickets detect tiny differences in the pulse rates of male courtship songs, which differ between species. They will not mate

with males of another species.• Closely-related species of Laupala that live on one island have no clear

physical differences, they have similar diets and possess no physiological differences that would prevent them from interbreeding.

• Discuss how different types of reproductive isolating mechanisms have contributed to the rapid evolution of Laupala crickets in all the Hawaiian Islands.

• 2009

Question 6 (a)

• Polystichum ferns are found in both Australia and New Zealand. The NZ species are found in a range of habitats from coastal to alpine regions, and in different layers of the forest.

• The speciation of NZ Polystichum ferns was originally thought to have begun in NZ when Gondwanaland split up 85 million years ago.

• However, recent DNA evidence suggests that the earliest divergence from a common NZ ancestor was only 13 million years ago.

• (a) Describe why the DNA evidence suggests that the speciation of NZ Polystichum ferns did not begin when Gondwanaland split up.

• 2009

Question 6 (b)• Polystichum ferns are found in both Australia and New

Zealand. The NZ species are found in a range of habitats from coastal to alpine regions, and in different layers of the forest.

• The speciation of NZ Polystichum ferns was originally thought to have begun in NZ when Gondwanaland split up 85 million years ago.

• However, recent DNA evidence suggests that the earliest divergence from a common NZ ancestor was only 13 million years ago.

(b) Discuss how a combination of both geological processes in New Zealand’s history and biological processes in the fern populations have led to the adaptive radiation of NZ Polystichum ferns.2009

Question 6 (c)

• A group of Hawaiian Laupala crickets have a very rapid rate of speciation.

• Female Laupala crickets detect tiny differences in the pulse rates of male courtship songs, which differ between species. They will not

mate with males of another species.• Closely-related species of Laupala that live on one island have no clear

physical differences, they have similar diets and possess no physiological differences that would prevent them from interbreeding.

• Two closely-related species of Hebe are thought to have been the result of a polyploidy event. H. gracillima (2n = 80) and H. venustula (2n = 120).

• (c) Explain how a polyploidy event could have lead to these two species of Hebe.

Question 6 (d)