Topic 4.1: Species, communities, and ecosystems

Question 1

Definition of ecology

Answer 1

The study of the relationships between living organisms and their environment.

Question 2

Definition of species

Answer 2

A group of organisms that can potentially interbreed to produce fertile offspring.

Question 3

Definition of population

Answer 3

A group of organisms of the same species, living in the same area at the same time.

Question 4

Definition of community

Answer 4

A group of different populations living together and interacting with each other in a given area.

Question 5

Definition of habitat

Answer 5

The environment in which a species normally lives

Question 6

Definition of ecosystem

Answer 6

The interaction of a community and its abiotic environment

Question 7

What might happen if two populations of a species never interbreed?

Answer 7

Develop differences in their characters

Question 8

Can members of the same species be reproductively isolated in separate populations?

Answer 8

Yes. This does not mean that they are different species if interbreeding is functionally possible.

Question 9

Main features of the members of a same species (2)

Answer 9

a) Similar physical characteristics

b) Can interbreed and produce fertile offspring

Question 10

Exception to the definition of species

Answer 10

Some organisms reproduce asexually

Question 11

Main modes of nutrition (2)

Answer 11

a) Autotrophs

b) Heterotrophs

Question 12

Autotrophs definition

Answer 12

Synthesize their own organic molecules from inorganic molecules (through photosynthesis)

Question 13

Heterotrophs definition

Answer 13

Obtain organic molecules from other organisms (via different mechanisms and sources)

Question 14

Classification of heterotrophs (3)

Answer 14

a) Consumers
b) Saprotrophs
c) Detritivores

Question 15

Consumers definition

Answer 15

Feed on living organisms by ingestion

Question 16

Subclassification of consumers (4)

Answer 16

a) Herbivores (Plant matter)
b) Carnivores (Animal matter)
c) Omnivores (Both matters)
d) Scavengers (Decaying carcasses)

Question 16

Saprotrophs definition

Answer 16

Obtain organic nutrients from dead organims by external digestion

a) Secreting enzymes
b) Absorbing matter

Question 17

Detritivores definition

Answer 17

Obtain nutrients from detritus (decomposing and fecal matter) by internal digestion

Question 18

Mixotrophs definition

Answer 18

Use both modes of nutrition (e.g., Euglena gracilis)

Question 19

Questions to classify species based on their modes of nutrition (2)

Answer 19

a) Does it possess cell walls?

b) Does it feed on dead organic matter?

Question 20

What are ecosystems able to do?

Answer 20

Be sustainable over long periods of time

Question 21

Requirements for sustainability in an ecosystem (3)

Answer 21

a) Energy availability (e.g., sunlight)
b) Nutrient availability (e.g., decomposers)
c) Waste recycling (e.g., detoxifying bacteria)

Question 22

Mesocosms definition

Answer 22

Small, enclosed environments under controlled conditions

Question 23

Mesocosms function (2)

Answer 23

a) Test what types of ecosystems are sustainable

b) Find out the effects of varying the conditions of an ecosystem

Question 24

Nutrients definition

Answer 24

Materials required by organisms for survival (e.g., N / P / Ca)

Question 25

What is needed for an ecosystem to provide a limited amount of nutrients?

Answer 25

They must be constantly recycled

Question 26

Nutrient Cycling

Answer 26

a) Autotrophs convert inorganic nutrients into organic matter
b) Heterotrophs ingest organic molecules and may release inorganic byproducts.
c) Saprotrophs break down the nutrients in dead organisms and return them to the soil.

Question 27

Positive species association

Answer 27

If two or more species are always found in the same habitat

a) Predator / prey relationship
b) Symbiotic interaction

Question 28

Negative species association

Answer 28

If species do not share the same habitat

a) Competition

Question 29

Quadrat sampling function

Answer 29

Determine the presence of a species in a given area

Question 29

Quadrat sampling function

Answer 29

Determine the presence of a species in a given area

Question 30

Quadrat sampling method

Answer 30

a) Rectangular frame placed in an area (repeat sampling)

b) Species numbers within the frame are counted.

Question 31

Function of Chi-Squared Test in Ecology

Answer 31

To determine if there is a statistically significant association between the distribution of two species.