20. Human influences on ecosystems
A section of Biology, 0610
Listing 10 of 393 questions
The giant quiver tree, Aloe pillansii, shown in , is an endangered species. These long-lived trees grow in harsh environments. Some populations of A. pillansii are found within the Richtersveld National Park, but one population is found just outside on a mountain called Cornell’s Kop in southern Africa. State the genus of the giant quiver tree. Explain why the A. pillansii trees on Cornell’s Kop represent a population. Suggest three reasons why the giant quiver tree is an endangered species. It was estimated in 2005 that the total number of giant quiver trees in the wild was less than 3000, which is considered to be very low compared with other tree species. Explain the risks to a plant species of having very small numbers. The population of A. pillansii trees on Cornell’s Kop was surveyed and photographed at four sites, A to D, from 1937 onwards. Researchers took photographs at all four sites in 2004 and compared them with the original photographs. The results are shown in Table 5.1. Table 5.1 site date of the original photograph number of living trees in the original photograph number of living trees in number of dead tree stumps average annual mortality rate / percentage of deaths per year A 1.0 B 0.9 C 2.1 D 5.6 Calculate the percentage decrease in the number of living trees at site B from 1953 to 2004. Show your working and give your answer to the nearest whole number. % Describe what the analysis of the photographs shows about the population of A. pillansii on Cornell’s Kop.
0610_s17_qp_41
THEORY
2017
Paper 4, Variant 1
View
is a photograph of a yellow-shouldered Amazon, Amazona barbadensis, a species of parrot found along the Venezuelan coast of the Caribbean. State the vertebrate group that includes A. barbadensis and give two features that are used to classify animals into this group. vertebrate group feature 1 feature 2 This species is subdivided into several populations on the mainland and on the islands of Margarita and Bonaire. Scientists believe that yellow-shouldered Amazons rarely travel between these places. Explain what biologists mean when they refer to populations of animals, such as A. barbadensis. The number of yellow-shouldered Amazons on Margarita Island had decreased to 700 parrots by 1989. The population then increased to 1600 parrots by 2009. Part of this increase was due to the release of captive-bred parrots on the island. This is one of the few successful release programmes of parrots. A similar release programme in Arizona in the 1980s of a different species of parrot was not successful. Suggest why release programmes for captive-bred parrots were not successful. Some captive breeding programmes involve very small numbers of animals. Outline the disadvantages of such programmes. Many biologists think that it is better to conserve ecosystems rather than individual species, such as parrots. Explain the advantages of conserving ecosystems.
0610_s17_qp_43
THEORY
2017
Paper 4, Variant 3
View
shows a tropical forest where the trees have been cut down. State the name of the type of habitat destruction shown in . Describe two reasons why humans destroy habitats such as tropical forests. is a graph showing the estimated area of trees that have been removed from tropical forests between 2001 and 2017. 60 000 70 000 80 000 90 000 100 000 110 000 120 000 130 000 140 000 150 000 160 000 170 000 180 000 2001 2002 2003 2004 2005 2006 2007 2008 2009 year 2010 2011 2012 2013 2014 2015 2016 2017 estimated area of trees removed from tropical forests / km2 State the year which had the lowest estimated area of trees removed from tropical forests on . State the area of trees removed in 2012 on . km2 A student made three statements about the data in : 1 The number of trees cut down increases every year. 2 The number of trees cut down in 2014 was three times more than the number of trees cut down in 2003. 3 Fewer trees were cut down in 2017 than in 2016. Complete Table 7.1 by using the data in to decide if each statement is true or false and state the evidence that supports your decision. Table 7.1 statement number true or false evidence from 1 shows pollution in a marine environment and shows pollution in a land environment. State the name of one source of pollution for each of the environments shown in and . marine land
0610_s20_qp_31
THEORY
2020
Paper 3, Variant 1
View
There are three species of rhinoceros in Asia. shows an Indian rhinoceros, Rhinoceros unicornis, in a national park being observed by tourists who are riding on an elephant. The International Union for Conservation of Nature (IUCN) collects data on animal species and places them into categories based on estimated numbers. Table 4.1 summarises the conservation status of the three species of rhinoceros, as available in 2020. Table 4.1 species location approximate number in the wild approximate number in captivity IUCN category Indian rhinoceros Rhinoceros unicornis national parks in south Nepal and north India vulnerable Javan rhinoceros Rhinoceros sondaicus one national park in Java, Indonesia critically endangered Sumatran rhinoceros Dicerorhinus sumatrensis national parks in Sumatra and Borneo in Indonesia In 2013, Cincinnati Zoo in the USA announced that they were hoping to breed together rhinoceros that were brother and sister as part of their captive breeding programme. Discuss the problems that using such closely related animals might have for the conservation of rhinoceros. Captive breeding programmes often use artificial insemination. Outline the process of artificial insemination.
0610_s21_qp_43
THEORY
2021
Paper 4, Variant 3
View
Questions Discovered
393