Population dynamics

Question 1

Name the three types of niches and describe each one

Provide case study

Answer 1

Ecological niches refers to the part of the ecosystem occupied by an organism. It is the role the organism plays in the larger ecosystem.

The Fundamental niche is the potential niche they would occupy if there was no competition.

The realised niche is the actual niche due to limitations caused by other organisms.

CS:
Koalas
suitable for koalas to have a widespread distribution along east coast. This distribution is not realised due to predation, disease, fires and drought.

Question 1

describe results of symbiosis

Answer 1

interactions between biotic factors create opportunity of resources available within an ecosystem

increase in biodiversity and more resilient ecosystems

Question 2

define the 4 symbiotic relationships with examples

Answer 2

Mutualism (both species benefit from the interaction +/+)

Commensalism (benefits one organism while not affecting the other +/0)

Parasitism (benefits one organism while harming the other +/-)

Ammensalism (harms one organism with no benefit to the other -/0)

Question 3

what are the 3 main relationships within an ecosystem

Answer 3

competition

symbiotic

prededation

Question 4

describe predation prey relationship with mention to the graph

Answer 4

a relationship where the predator benefits and the prey is killed.

abundance of predator and prey fluctuates however prey always peaks first and predator population is the delay of prey

Question 5

describe competition relationship

Answer 5

where two or more species (interspecific) or individuals of the same species (intraspecific) independently act and compete for the same resources

Question 6

what are the 3 main selection pressures

Answer 6

resource availability- food, habitat, shelter, mates

environmental conditions- temp, weather, geographical access

biological factors- predators, pathogens

Question 7

Define ecosystem

Answer 7

community of interacting organisms and their physical environment

Question 8

List 6 abiotic factors

Answer 8

temperature, water, buoyancy, viscosity, air pressure, light penetration

Question 9

what do abiotic factors effect within an ecosystem?

Answer 9

abundance and distribution of ecosystems according to the needs of organisms (tolerance range)

Question 10

list terrestrial vs aquatic abiotic factors

Answer 10

terrestrial- water availability, rain, shelter climate

aquatic- light availability, salinity, dissolved oxygen, depth

Question 11

define permeable

Answer 11

things can penetrate through it.

Question 12

what is the process of osmosis?

Answer 12

osmosis is the process of water moving from a low concentration of solute to a high concentration of solute; the water goes through a semi permeable membrane

Question 13

define abundance and distribution

Answer 13

abundance- how much

distribution- how evenly spread

Question 14

define salinity

Answer 14

the amount of salt in a body of water. All natural water contains salt but some contain more than others

Question 15

how do fish keep their internal water levels constant? explain how this is different for salt water fish and freshwater fish

Answer 15

they alter how concentrated or dilute their urine is.

freshwater fish
-live in a body of water with low salt content.
-through osmosis water travels into them through their permeable skin.
-release diluted urine

saltwater fish
-live in a body of water with high salt content
-release concentrated urine
-through osmosis water will flow out the fish

Question 16

state the 3 factors of biodiversity

Answer 16

species diversity
ecosystem diversity
genetic diversity

Question 17

what factors can effect biodiversity?

Answer 17

selection pressures
human impact
health of planet is effected by biodiversity

Question 18

define the following terms…
ecosystem
community
population
organism

Answer 18

ecosystem- made up of organisms living in an area that interact with each other, biotic and abiotic

community- a community of organisms. biotic but not abiotic factors. The biotic factors within an ecosystem

population- group of organisms of the same species living together in a defined geographical area

organism- individual of a species

Question 19

what is meant by the term carrying capacity

Answer 19

the maximum equilibrium number of individuals of a species that can be supported indefinitely within an environment (shelter, water, mate availability)

Question 20

Describe Allelopathy state an example

Answer 20

Competition between plants

The production of specific biomolecules by one plant that can be detrimental or beneficial to another plant.

E.g Casuarina (she-oak) have allelochemicals in stems, leaves, roots and fruit which render soil around plant ecologically sterile (v. low nutrients for other plants)

Question 21

What are the consequences to competition?

Answer 21

it affects reproduction and survival rates.

Some species may be more successful competitors than others, driving them to very low numbers or even extinction.

Question 22

Describe disease in an ecosystem, provide a case study

Answer 22

A disease is any process that adversely affects the normal functioning of a living organism. Diseases can be infectious (caused by a pathogen) and non-infectious

Genetic variation in the host population can limit the spread of a pathogen. In a genetically diverse host population there is a higher likelihood of resistant individuals.

Disease alters the balance in food webs and some organisms can become endangered due to disease.

CS:
Tasmanian devils are susceptible to devil facial tumour disease (DFTD) which is a transmissible cancer passed when an infected animal bites another and transmits some cancer cells into the wound.

Question 23

Describe Extinction
Provide Case Study

Answer 23

Extinction is the death of all the members of one species.

Major extinction- when a number of different species become extinct around the same time.

Remaining species- take advantage of the changes environment and available resources.

CS
Recent extinction: Tasmanian Tiger

The last known Tasmanian tiger died from exposure in an enclosure in Hobart Zoo in 1936 after the zookeeper forgot to secure it at night.