MODULE 4

Question 1

What is an abiotic factor?

Answer 1

Physical rather than biological- aren’t living or derived from living organisms (dirt, temperature, sunlight)

Question 2

What are biotic factors?

Answer 2

Are related to living organisms (plants, animals and bacteria)

Question 3

What is an ecological niche?

Answer 3

The specific region that an organism takes within an ecosystem in response to influences from abiotic and biotic factors

Question 4

What is an example of a biological niche?

Answer 4

Marsupial moles are found only in Australia, live entirely underground have no eyesight and feed on insects

Question 5

How is ocean light and co2 an example of unequal abiotic factor distribution that impacts an ecosystem?

Answer 5

The amount of sunlight, effects the amount of organisms that live there. Blue light can penetrate 300m, red light only penetrates 50m (carrying out photosynthesis)
Below these, no photosynthesis can occur and there is little plant life

Question 6

What is the photic and epipelagic zone?

Answer 6

Photic- area where plants carry out photosynthesis

Epipelagic zone- surface to 200m- 90 percent of all life

Question 7

What is predation?

Answer 7

A relationship in which a predator benefits and the prey is killed (lion and the wildebeest)

Question 8

What is intraspecific competition?

Answer 8

Individuals from the same species acting to secure the same resources such as food, shelter and mates

Question 9

What is interspecific competition?

Answer 9

Individuals from different species acting to secure the same resources such as food shelter and mates (zebra and wildebeest)

Question 10

What is symbiosis?

Answer 10

A relationship between two species living in close proximity in which at least one of them benefits

Question 11

What is mutualism?

Answer 11

Both species benefit from the interaction (oxpeckers land on rhinos or zebras and eat the parasites on their skin- the oxpeckers get food and the zebras get pest control)

Question 12

What is commensalism?

Answer 12

One species benefits from the interaction, whilst the other neither benefits or is harmed (the golden jackal following a tiger to feed on leftovers from its kills- strangler figs)

Question 13

What is parasitism?

Answer 13

One species benefits from the interaction whilst the host is harmed but not killed ( a flea on a dog)

Question 14

What is allelopathy?

Answer 14

An organism produces one or more biochemicals that influence germination, growth, survival and the reproduction of other organisms (tree roots pulling more water from the soil so other plants can’t thrive)

Question 15

What is carrying capacity?

Answer 15

The maximum, equilibrium number of individuals of a species that can be supported indefinitely in a given environment

Question 16

How does energy change through the food chain?

Answer 16

Moving along a food chain, there will always be less energy valuable and a smaller biomass

Question 17

What are the different kinds of consumers?

Answer 17

Tertiary consumers (eagle), secondary consumers (quoll), primary consumers (grasshopper), producer (grass)

Question 18

What are the effects of instraspecific competition?

Answer 18

More influential than interspecific, leads to a reduction in fitness for both individuals, but the more fit individual survives and is able to reproduce.

Question 19

What are the effects of predation?

Answer 19

Predators affect the distribution and abundance of their prey. If a species can reproduce as much as it is hunted the population will remain stable. As prey are consumed, their numbers decline, and the food for predators decline, causing themselves to decline

Question 20

What are the effects of interspecific competition?

Answer 20

The effects of interspecific competition can also reach communities and can even influence the evolution of species as they adapt to avoid competition.

Question 21

What are the effects of symbiosis as a whole?

Answer 21

Increased evolutionary diversification, development of new species, new capabilities for organisms, enhance evolutionary fitness, increased biodiversity (coral reefs exist because coral has a symbiotic relationship with photosynthetic algae- reefs provide an environment for fish and marine invertebrates)

Question 22

What are the effects of mutualism?

Answer 22

Species A is at carrying capacity, when species B is introduced, both species increase and improve until a new carrying capacity is reached and then it plateaus and moves up and down the carrying capacity. (Zebra and pests)

Question 23

What are the effects of commensalism?

Answer 23

Species A is at carrying capacity, and when Species B is introduced, they remain at carrying capacity, whilst Species B increases then plateaus. (Egret and cattle)- no change in cattle population

Question 24

What are the effects of parasitism?

Answer 24

Species A is at carrying capacity, and when Species B is introduced, Species A decreases significantly, whilst Species B increases. (Cattle health is impaired- decrease in cattle population, tick numbers increase rapidly)

Question 25

What are the effects of infectious diseases?

Answer 25

Species A begins at carrying capacity, and when the pathogen (Species B) is introduced, the population of Species A significantly decreases whilst the pathogen increases

Question 26

What is a sampling technique?

Answer 26

Sampling techniques determine the distribution and abundance of a species when direct counts or a census isn’t possible due to size, amount, mobility or isolation

Question 27

What are the three kinds of sampling techniques?

Answer 27

Random quadrats (abundance), transects (distribution and abundance) and capture (abundance)

Question 28

What are random quadrats?

Answer 28

Throw over shoulder (chance not choice) and is used for plants or immobile animals. It assumes even distribution- once numbers are counted an average is generated

Question 29

What are transects?

Answer 29

Used to measure the distribution of plants or immobile animals- random straight line is drawn through the study area and the presence of any species along the set intervals

Question 30

What is capture and recapture?

Answer 30

Used for highly mobile organisms that are difficult to observe. (1. Capture the individuals and mark them. 2. Return them to the wild population 3. Recapture a second sample of the population. 4.Record the number of individuals in s2 that are marked (m2) 5. Use an equation to determine an estimate of the total population)

Question 31

How do you calculate the estimate of a total population in capture and recapture sampling?

Answer 31

s1 x s2 divided by m2 (s1=sample 1, s2=sample2, m2=individuals in s2 that are marked)

Question 32

What is an extinction event?

Answer 32

A widespread and rapid decrease in the biodiversity on Earth.

Question 33

What are the differences between eras and periods?

Answer 33

Era- a major division of geological time, usually characterised by major and specific events
Period- the basic unit of geological time which a single rock is formed

Question 34

What are the five major extinction events?

Answer 34

Ordovician-Sicilian extinction (86%), Devoninan extinction (75%), Permian-triassic (96%), Triassic-Jurassic (80%), Cretaceous (76%)

Question 35

What is the cretaceous period extinction?

Answer 35

Most recent, 65 million years ago, a combination of volcanic activity, climate change and asteriod impact, temperatures fell, sea levels dropped and sunlight was blocked- extinction of 80% of all species including the dinosaurs, plants, autotrophs and marine invertebrates-rise of mammals

Question 36

What is the Australian megafauna extinction?

Answer 36

The procoptodon goliah and diprotodon australis- 30-40 thousand years ago, could be due to climate change at the end of the last ice age causing scarcity of vegetation and surface water or by overhunting by first Australians- unable to compete with their smaller counterparts

Question 37

What is the Tasmanian Tiger extinction?

Answer 37

A large dog like carnivorous marsupial, went extinct on the mainland 2000 years ago and remained on Tasmania- bounties were paid to eradicate the species as a pest, competition with introduced species, habitat loss and population fragmentation- 1936 extinction

Question 38

What is the proposed ‘Anthropocene’ extinction?

Answer 38

Current extinction event caused by human action- co2 emissions, global warming, habitat destruction, overconsumption, nuclear weapons, plastics etc
1000 to 10000 times higher than the natural extinction rate (WWF)

Question 39

What is geological evidence?

Answer 39

Study of rocks, minerals and formations in the outer cast of the planet that provide evidence of changes in ecosystems

Question 40

What is paleontological evidence?

Answer 40

The study of fossil remains that prove the changes in ecosystems

Question 41

How do Aboriginal rock paintings provide evidence for past changes in ecosystems?

Answer 41

Rock paintings of a thylacine located in Urbir in the East Alligator region of Kakadu NT, thylacine paintings have been dated 50000 to 60000 y/o, the types and numbers of paintings change over time showing a change in ecosystems and thylacine abundance- climate change

Question 42

How do rock structures and formations provide evidence for past changes in ecosystems?

Answer 42

Iron bonding are distinct layers of sedimentary rocks with iron oxides- first appear in 3 billion y/o rocks- at this time the numbers of photosynthetic cyanobacteria increased releasing oxygen that saturated the atmosphere + oxidised iron dissolved into oceans.- indicates a different ecosystem to now

Question 43

How do marine fossils provide evidence for past changes in ecosystems?

Answer 43

Marine fossils in the desert show a different location and transformation of the environment, showing there were different conditions and landscapes. It proves that areas that were once underwater are now deserts.

Question 44

How does ice core drilling provide evidence for past changes in ecosystems?

Answer 44

Ice cores are cylinders of ice drilled out of ice sheets- snow falling in these regions doesn’t melt and encloses small bubbles of gases (co2 and ch4) and pillars in the atmosphere- results indicate conditions on earth had changed

Question 45

What is radiometric dating?

Answer 45

Used to determine the age of an object by using half-lives- better and more accurate than relative dating

Question 46

What is iron banding and how does it provide evidence for past ecosystems?

Answer 46

Distinct layers of sedimentary rock containing iron oxides. They appear in rocks dated 3byo due to the increase in photosynthetic cyanobacteria releasing greater levels of oxygen. This resulted in the oxidation of iron in the oceans indicating the past changes and environmental conditions on earth.

Question 47

What does ice-core drilling tell us?

Answer 47

Allows scientists to construct a climate record, with the temperature and chemical profiles of the atmosphere through history. This understanding of past climates and their effects on ecosystems enables scientists to predict future climatic events.

Question 48

Why do marsupials thrive and dominate in Australia?

Answer 48

Larger mammals went extinct due to abiotic factors, which removed competition allowing marsupials to dominate.
→ Marsupials have a lower resting metabolic rate and survive on a lower energy requirement than similar sized mammals.
→ Less energy investment in gestation/raising young = better chance of surviving unpredictable fluctuations in climate

Question 49

Why do sclerophyll thrive and dominate in Australia?

Answer 49

As Australia split from Antarctica, the climate began drying out. As a result, the rainforests shrunk and sclerophyll plants adapted to aridity, poor soil nutrition and increased fires evolved. This is supported by fossil evidence.
→ waxy leaves to prevent excessive water loss
→ some require fire for reproduction

Question 50

Maruspial statistics (vs placental animals)

Answer 50

-4000 placental species in the world, only 330 marsupials- not many endemic placentals in Australia

Question 51

What are examples of marsupials and sclerophyll plants?

Answer 51

Marsupials-koalas, kangaroos

Sclerophylls-Acacias and eukalpypts

Question 52

What is the evidence for fluctuations in Co2, sea and temperature levels in Australia?

Answer 52

Rainforest and marine fossils in the desert, ice core drilling samples (all show a different ecosystem and different levels