4.1 SPECIES AND ECOSYSTEM

Question 1

Ecosystem

Answer 1

A community of organisms and their abiotic environment

Question 2

Ecology

Answer 2

The study of relationships between living organisms, or between organisms and their environment

Question 3

Community

Answer 3

A group of populations living together and interacting with each other within a given area

Question 4

Habitat

Answer 4

The environment in which a species normally lives, or the location of a living organism

Question 5

Population

Answer 5

A group of organisms of the same species who live in the same area at the same time

Question 6

Species

Answer 6

A group of organisms that can interbreed and produce fertile offspring

Question 7

Gene pool

Answer 7

A collection of genes (along with their associated allelelic forms) found in a population.

All members of a species share a common gene pool and number of chromosomes in their haploid cells.

Question 8

Autotroph

Answer 8

An organism that synthesises simple inorganic substances (obtained from the abiotic environment: air,
water and soil) into organic molecules (carbon, nitrogen, hydrogen, oxygen and phosphorus)

Question 9

Mixotroph

Answer 9

Organisms which use both autotrophic and heterotrophic modes of nutrition.

Question 10

Chemosynthesis

Answer 10

energy from oxidation of inorganic molecules

Question 11

Heterotrophs

Answer 11

An organisms that obtains organic molecules from other organisms

Question 12

Saprotroph

Answer 12

Heterotrophs (usually fungi) that obtain organic nutrients from dead organisms by external
digestion

Question 13

External Digestion

Answer 13

the process by which organisms secrete enzymes into their environment to break down organic debris around them.

Question 14

Detritivore

Answer 14

Heterotrophs (usually animals) that obtain organic nutrients from detritus via internal
digestion

Question 15

Internal Digestion

Answer 15

the process by which an organism digests its food inside of its body,
usually with the aid of a digestive tract.

Question 16

Abiotic factors

Answer 16

Non-living parts of an environment.

Physical:
Humidity, Wind, Temperature, Light, Water, Altitude

Chemical:
pH, Dissolved oxygen concentrations, Nutrients, Salinity

Question 17

Biotic Factors

Answer 17

all of the living and once-living things in the environment. Including substances that came from living things.

Question 18

Symbiosis

Answer 18

Means ‘living together’ and refers to the following outcomes of interactions between populations.

Question 19

Mutualism

Answer 19

a type of symbiotic relationship where both organisms benefit.

Question 20

Commensalism

Answer 20

a type of symbiotic relationship where one organism benefits and the other is unaffected.

Question 21

Parasitism

Answer 21

a type of symbiotic relationship where one organism benefits and the other is harmed.

Question 22

Predator-prey relationship

Answer 22

one in which one organism hunts and feeds on another.

Question 23

Nutrients

Answer 23

Material required by an organism, and include
elements such as carbon, nitrogen and phosphorus.

Question 24

Nutrient cycling

Answer 24

helps to move organic molecules and minerals through the food chain and back into the soil where they can be taken up by plants to re-enter the food chain.

Question 25

The nutrient cycle

Answer 25

Autotrophs convert nutrients from inorganic form into organic molecules, e.g. carbon dioxide
becomes glucose

Heterotrophs ingest organic molecules and use them for growth and respiration, releasing
inorganic byproducts

Saprotrophs break down organic nutrients to gain energy and in the process release nutrients
back into inorganic molecules. This ensures the continuing availability of nutrients to autotrophs.