Module 3: Biodiversity

Question 1

Process of natural selection

Answer 1

1. In any population there are variations - all the members of one species are not identical
2. In any generation there are offspring that do not reach maturity and do not reproduce due to their inability to cope with selection pressures e.g. change in the environment (natural selection) - the characteristics of these organisms are removed from the population
3. Those organisms that survive and reproduce are well suited to the environment; they have favourable variations (survival of the fittest)
4. Favourable variations are passed onto offspring; they become more and more common in the population

Question 2

Who discovered Natural Selection?

Answer 2

Charles Darwin

Question 3

What is natural selection?

Answer 3

the process by which the environment selects characteristics that are favourable to a species survival determining if they live or die out.

Question 4

What does natural selection rely on?

Answer 4

variations in the population

Question 5

What causes the variation in natural selection?

Answer 5

These variations would initially be a result of a random mutation, which results in a new characteristic being introduced into a species.

Question 6

What decides whether these mutations change things?

Answer 6

It is then up to natural selection to determine whether the environment will favour that characteristic and individuals of the species that possess it

Question 7

What passes on these characteristics?

Answer 7

interbreeding passes the characteristic on to future generations.

Question 8

What is a result of natural selection?

Answer 8

Over time this can results in a population change where the desirable characteristic is selected for.

Question 9

peppered moth natural selection:

Answer 9

industrial revolution presented conditions that through natural selection caused the white moths to die out and the black moths to thrive.

Question 10

Convergent evolution:

Answer 10

The evolution through natural selection of similar features in unrelated groups of organisms

Question 11

convergent example

Answer 11

Dolphins and sharks

Question 12

Divergent evolution:

Answer 12

Separated populations typically diverge (may be from genetic drift or natural selection) causing separated populations to gradually become different

Question 13

Divergent example:

Answer 13

Galapagos finches

Question 14

Purpose of selective breeding

Answer 14

to breed livestock to meet specific requirements, especially food

Question 15

What does selective breeding help identify?

Answer 15

-The technique is to identify desirable qualities e.g. good quality meat/ high meat production and breed together individuals with those qualities, so the trait is reliably passed on.

Question 16

Selective breeding example:

Answer 16

Belgian blue cows

Question 17

What is Spatial sorting?

Answer 17

• In any dispersing population, there are traits that will accumulate in different regions of the dispersing population
• Spatial sorting can only occur if natural selection does not oppose it

Question 18

Compare spatial sorting and natural selection:

Answer 18

• They are both ways in which evolution occurs
• They both rely on variations in the population, inheritance of traits and time
• However, natural selection involves a selection pressure driving the survival of advantageous traits
• Whereas, spatial sorting involves traits leading to geographical dispersal with impacts on mating partner options.

Question 19

Cane toads are an example of…

Answer 19

selective breeding

Cane toads are a dispersing population with a high reproduction rate. Toads with advantageous traits such as long legs and high endurance are more likely to be located at the invasion front. Hence, they reproduce with toads that have the same traits causing these traits to be more common.

Question 20

define biodiversity

Answer 20

The range of organisms that makes up the living world and the ecosystems they live in.

Question 21

whats a trophic cascade?

Answer 21

an ecological process that starts at the top of the food chain

Question 22

What is a community?

Answer 22

A community is a group of different species living together and interacting with one another in a particular habitat.

Question 23

What do all ecosystems have?

Answer 23

1. The sun: the source of energy in the ecosystem (energy is not recycled in an ecosystem).
2. Nutrients: Food, which is matter (matter is constantly recycled in natural ecosystems)
3. Organisms These include –

Question 24

describe the distribution of the prickly pear (this E.G. is in syllabus!!)

Answer 24

introduced to Australia with the first settlers in 1788 to use the insects that feed on it. It moved around Australia by people as food source. Methods for removal were not successful. Moths were used to kill the species. After 7 years, population was controlled.

Question 25

How was the population of the prickly pear controlled.

Answer 25

Methods for removal were not successful. Moths were used to kill the species. After 7 years, population was controlled.

Question 26

what are two examples that support darwin’s theory

Answer 26

finches of the Galapagos islands + Australian flora and fauna

Question 27

explain how the finches of Galapagos support Darwin’s theory

Answer 27

each species of finch found had differing forms of beaks. These were the traits altered by natural selection.
Each island of the Galapagos has different environmental conditions, including foods available, These provide selection pressures for birds to migrate to different islands.

Question 28

explain how the Australian flora and fauna supports Darwin’s theory

Answer 28

Darwin noticed that the platypus and english water rat occupied a similar ecological niche.
He concluded that animals that exist in similar conditions might have no resemblance to each other. This is because the water rat and platypus do not share a common ancestor.

Question 29

microevolutionary changes (defintion)

Answer 29

it is the changes in populations or species over a short period of evolutionary time. An accumulation of these changes can result in speciation.

Question 30

what are the four main processes that drive microevolutionary changes

Answer 30

mutation, migration, genetic drift, natural selection

Question 31

evolution of the platypus (E.G. from syllabus)

Answer 31

280 mya (million years ago), they diverged from lineage they shared with birds and reptiles. 200 mya, the egg laying mammal spilt from mammalian lineage. The only branch that remained were platypus and some echidna. They lost their stomachs in this evolution.

Question 32

what does punctuated equilibrium state

Answer 32

States that species undergo rapid change from one form to another. There are some periods of time where there are short bursts of rapid change to become more stable in an environment. Rapid changes are usually in response to sudden environmental changes.

Question 33

list the evidence supporting evolution

Answer 33

biochemical evidence, comparative anatomy, comparative embryology, biogeography, techniques used to date fossils

Question 34

what is comparative anatomy

Answer 34

comparing the structures of organism.
Features that have fundamental similarities based on a common ancestor are homologous features. They evolve to have different functions, but have similar structures. E.G. the forearms of mammals have the same arrangement of bones, but have different functions.

Question 35

what is comparative embryology

Answer 35

comparing the developments of different species’ embryos.
the embryo of organisms that share a common ancestor will pass through similar stages of development. E.G. human embryos gill slits, like fish.

Question 36

what is biogeography

Answer 36

the study of geographic distribution of organisms and the factors affecting them. it includes:

• shifting continents
• changing climates
• fluctuating sea levels

Question 37

2 techniques used to date fossils are:

Answer 37

1. absolute dating

2. relative dating

Question 38

explain absolute dating

Answer 38

absolute dating looks at radioactive isotopes in the rock and how it has decays,
Radioisotopes decays into different forms, at rates that are constant for an element. The rate of decay is not influenced by the nature of the rock and environmental conditions they are exposed to.

Question 39

explain relative dating

Answer 39

relative dating compares the deep (old) layers of rock to the closer (young) layers.

Question 40

2 examples of modern day evolutionary change:

Answer 40

1. cane toad

2. antibiotic resistant strains of bacteria

Question 41

explain the cane toad as a modern day evolutionary change:

Answer 41

When cane toads were first introduced to QLD, they were not very active. They evolved larger, faster and have stronger and longer legs. Their behaviour changed too.
The distribution is continually expanding (60km/year). Fast toads breed with other fast toads, meaning the generations are becoming faster. In each generation, the fastest offspring reproduce

Question 42

explain the antibiotic resistant strains of bacteria as a modern day evolutionary change:

Answer 42

some bacteria are sensitive and can be killed by antibiotics, and some are resistant and cannot be killed. Antibiotics are used to kill as many pathogenic bacteria as possible.
Bacteria reproduce asexually, meaning subsequent generations are almost perfect clones. This also means they can reproduce very quickly and rapidly evolve. Bacteria can transfer genes to another, meaning they can quickly develop genetic variation and new traits,
Because of natural selection, the bacteria become very resistant and can quickly evolve.