population dynamic

Question 1

what is an ecosystem

Answer 1

an area where a community of biotic factors interact with each other and the abiotic factors that exist around them.

e.g., desert, grassland, freshwater river, estuary, human skin/scalp, animal fur

Question 2

what are biotic factors?

Answer 2

the living things found in an ecosystem; these are usually those whose natural habitat is the identified ecosystem.

Question 3

examples of biotic factors

Answer 3

plants, animals, bacteria, humans

Question 4

what are abiotic factors?

Answer 4

the non-living things present in an ecosystem; these are either permanent or constantly changing but not uncommon to the ecosystem.

They cause the biotic factors to behave and adapt in order to survive.

Question 5

examples of abiotic factors

Answer 5

temperature, water availability, salinity, acidity of soil/water, air pressure etc

Question 6

what are introduced species?

Answer 6

organisms whose current ecological niche is not its usual habitat. This is either due to human introduction to the ecosystem or the organism found its way to that ecosystem

Question 7

what is a population?

Answer 7

A population is the quantity of organisms (same species or type of species) found in an ecosystem.

Question 8

what’s abundance?

Answer 8

Abundance of species refers to the number of individuals of that same species present in the named ecosystem.

high= this species is unlikely to be endangered
low= this species need to be protected and conserved.

Question 9

what is distribution?

Answer 9

Distribution of species refers to the spread of that same species that reside in the named ecosystem.

high= it means this species is either mobile and/or can adapt in multiple locations.
low= this species may prefer to exist as a community.

Question 10

what are the types of sampling techniques?

Answer 10

Quadrat
Transect
Capture-Release-Recapture

Question 11

what’s quadrat sampling?

Answer 11

the study area is divided into a grid of equal sized quadrats. count, measure or estimate organisms in each quadrat. This data is used to assess species abundance, distribution, and population density across the entire area.

Question 12

what’s transect sampling?

Answer 12

A transect is a 10-metre-long straight line across the study area. At one-metre intervals, whatever living thing is on, under or above the tagged mark is recorded.

Question 13

what is capture-release-recapture sampling?

Answer 13

A sample of animals is captured, harmlessly marked, and released. After time to mix back into the population, a second sample is captured. The proportion of marked individuals in the second sample is used to estimate the total population size with a formula.

Question 14

what are the effects of abiotic factors on abundance and distribution?

Answer 14

They set the limits for growth, reproduction, and survival, so species are only abundant where conditions match their needs. When conditions fall outside their tolerance, abundance drops or they disappear entirely.

Question 15

What is a biological relationship?

Answer 15

Relationships are connections between organisms. These can occur within the same species or among different species.

These can either be positive (beneficial) or negative (detrimental) or neutral (no effect) on the organisms involved.

Question 16

types of interrelationships

Answer 16

mutualism
commensalism
amensalism
exploitation
antibiosis

Question 17

what’s mutualism

Answer 17

Both species benefit from the relationship.

Often a close, long-term interaction (symbiosis).

Example: Birds eat parasites off elephants.
Bird gets food (+)
Elephant gets rid of parasites (+)

Question 18

what’s commensalism

Answer 18

One species benefits, the other is unaffected.
One-sided benefit.

Example: Vines grow on trees to reach sunlight.
Vine benefits (+)
Tree is not affected (0)

Question 19

what’s amensalism

Answer 19

One species is harmed, the other is unaffected.
Opposite of commensalism.

Example: Humans walking on grass.
Grass is damaged (–)
Humans are unaffected (0)

Question 20

what’s exploitation

Answer 20

one benefits, one is harmed

Predation: Predator kills and eats prey.
Herbivory: Animals eat plants.

Parasitism: Parasite harms host without immediately killing it.
Example: Parasite lays eggs in host.

Parasite benefits (+)
Host suffers (–)

Question 21

what’s antibiosis

Answer 21

One species produces chemicals that harm another.

Example: Eucalyptus trees release toxins from roots.

Eucalyptus benefits (+)
Nearby plants can’t grow (–)

Question 22

whats competition

Answer 22

Both species compete for the same limited resources.

Both are negatively affected.

Example: Fish fighting over food in a pond.
Fish A and Fish B both suffer (– / –)

Question 23

whats an ecological niche?

Answer 23

a location in the ecosystem where a species is usually found. In the niche, this species finds comfort and safety in finding food, water, and other factors to survive.

Question 24

whats a food chain?

Answer 24

A food chain is an outline of energy flow from a producer to a consumer or a set of consumers

Question 25

whats a food web?

Answer 25

A food web is a set of food chains in one ecosystem. The energy flow is represented by an arrow -->

Question 26

what are introduced species?

Answer 26

organisms whose current ecological niche is not its usual habitat either due to human introduction to the ecosystem or the organism found its way to that ecosystem

Question 27

impacts of introduced species:

Answer 27

positive = beneficial e.g. new food source for the animals hence local producers are less consumed negative = harmful e.g. another competition to the local consumers for food, habitat, or mate neutral = no effect e.g. occupies a space in the ecosystem but does not bother any species

Question 28

what are extinct species?

Answer 28

the organisms that did not survive and did not leave any offspring behind. Despite their ability to adapt, the selective pressures in their environment were harsher than usual. The offspring may have suffered too

Question 29

what are selective pressures?

Answer 29

changes in either abiotic factors or biotic member of the ecosystem. They 'pressure' organisms to adapt in response to survive. 'Selective' refers to the fact that not every organism will cope and adapt in the same manner. Some may adapt quickly while others not at all resulting in death. Selective pressures drive evolution to occur.