ESS (Ecology) End of Year Exam Grade 9

Question 1

Ecological interactions are important because…

Answer 1

can affect distribution and abundance
can influence evolution

Question 2

Symbiosis

Answer 2

the act of living together
- two organisms that live together
- temporarily or a longer time
- (usually) at least one of the organisms benefits from the relationship.

Question 3

Symbiotic relationships

Answer 3

mutualism, commensalism, parasitism, predation, competition

Question 4

Mutualism

Answer 4

both organisms benefit (both species provide resources or services to each other, enhancing fitness for both)

Question 5

Commensalism

Answer 5

one organism benefits, one organism is unaffected (ex: rhino/elephant - birds getting food and protection)

Question 6

Parasitism

Answer 6

one organism benefits on organism is harmed (ex: parasites feeding on plants, killing it) - reduces fitness of host

Question 7

Predation

Answer 7

one organisms benefits, one organism is killed (herbivore eating a plant, carnivore eating an animal)

Question 8

Competition

Answer 8

one organism benefits, one organisms harmed, or both (same or different species in competition for resources)

Question 9

Habitat

Answer 9

a physical area where a species lives
- they (species) also rely on the living and non-living things that surround them

Question 10

Food chain

Answer 10

the model we use to measure the energy that flows between organisms

Question 11

How are habitats described?

Answer 11

• using annual rainfall amounts
• average sunlight amounts
• annual temperature ranges
  *for plants the type of soil is also a significant feature in describing its habitat

Question 12

Niche

Answer 12

a role that an organism plays within its ecosystem
- the habitat in which the organism lives and the organisms patterns of living
- the resources it uses within the environment and the interactions it has with other species in the area
- what it eats and what eats it

Question 13

An organism

Answer 13

• may have many food options available to it in its environment
• may also be a food source for many potential predators and consumers

Question 14

Fundamental niche

Answer 14

all the possible food sources and interactions are called the organisms fundamental niche
- ex: would be all tree regions for a bird

Question 15

Realized niche

Answer 15

an organisms actual interactions
- ex: while a bird may inhabit any part of a tree, it may inhabit only the upper tree regions

Question 16

Two species with similar niches

Answer 16

two species may have overlapping niches, but they will not be completely identical
- competing for the same resources will lead one species to face the need to find a new food source or move to a different area

Question 17

Resource partitioning

Answer 17

adapting to more unique feeding
- this might allow two species with similar niches to exist together

Question 18

Interspecies competition

Answer 18

the situation when two species vie for a limited amount of the same resource
- interspecific = between different species
- infraspecific

Question 19

The competitive exclusion principle

Answer 19

that two species can’t exist together if they occupy exactly the same niche (competing for identical resources)
- one species will use the resources more efficiently and drive the other species to local extinction

Question 20

Resource partitioning

Answer 20

two species will alter their use of the niche to avoid direct competition, allowing for co-existence

Question 21

Flagship species

Answer 21

cute/endearing: aesthetically pleasing
- humans have decided are worth saving (pandas, dolphins, etc…)

Question 22

Keystone species

Answer 22

“ecosystem engineer”
a species that has a disproportionately large impact on its environment relative to its abundance
- play a vital role in maintaining the delicate balance of the ecosystems

Question 23

Trophic cascade

Answer 23

an ecological phenomena that occur when there is a top-down regulation of ecosystem structure and function. They involve a series of interactions where changes in one trophic level (a position in the food chain) have serious effects on other trophic levels.
- the effects can reverberate throughout the ecosystem, often leading to changes in biodiversity and overall ecological balance

Question 24

Greenworld hypothesis

Answer 24

how the trophic cascade (top-down) started

Question 25

Apex predator

Answer 25

stabilize and regulate the composition of an entire community/ecosystem

Question 26

Maximum sustainable yield

Answer 26

a number that cannot be exceeded if you want the population to recover