4.1 Species and Ecosystems

Question 1

What is a species?

Answer 1

A species is a group of organisms that can potentially interbreed to produce fertile, viable offspring

Question 2

can members from one species reproduce with another species?

Answer 2

Members of a single species are unable to produce fertile, viable offspring with members from a different species

Question 3

What happens when two different species interbreed?

Answer 3

When two different species do produce offspring by cross-breeding, these hybrids are reproductively sterile (e.g. liger, mule)

Question 4

What is a population?

Answer 4

A population is a group of organisms of the same species that are living in the same area at the same time

Question 5

Can organisms that live in different regions still be considered species?

Answer 5

Organisms that live in different regions (i.e. different populations) are reproductively isolated and unlikely to interbreed, however are classified as the same species if interbreeding is functionally possible

Question 6

What is a community?

Answer 6

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

Question 7

What is a habitat?

Answer 7

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

Question 8

What is an ecosystem?

Answer 8

A community and its abiotic environment (i.e. habitat)

Question 9

What is ecology?

Answer 9

The study of the relationship between living organisms, or between living organisms and their environment

Question 10

What ae the 3 ways organisms can obtain chemical energy?

Answer 10

autotrophs
heterotrophs
mixotrophs

Question 11

What are autotrophs?

Answer 11

Synthesises its own organic molecules from simple inorganic substances (e.g. CO2, nitrates)

Question 12

Where do autotrophs gain energy from?

Answer 12

Energy for this process is derived from sunlight (photosynthesis) or via the oxidation of inorganic molecules (chemosynthesis)

Question 13

What is the term used to refer to autotrophs?

Answer 13

Because autotrophs synthesise their own organic molecules they are commonly referred to as producers

Question 14

What are heterotrophs?

Answer 14

Obtains organic molecules from other organisms (either living / recently killed or their non-living remains and detritus)

Question 15

What are heterotrophs referred to as?

Answer 15

Because heterotrophs cannot produce their own organic molecules and obtain it from other sources, they are called consumers

Question 16

What are mixotrophs?

Answer 16

Certain unicellular organisms may on occasion use both forms of nutrition, depending on resource availability

Question 17

What is an example of a mixotroph?

Answer 17

Euglena gracilis possess chlorophyll for photosynthesis (autotrophic) but may also feed on detritus (heterotrophic)

Question 18

What are the 3 types of heterotrophs?

Answer 18

consumers
detritivores
saprotrophs

Question 19

What are consumers?

Answer 19

Consumers ingest organic molecules from living or recently killed organisms

Question 20

What are detritivores?

Answer 20

Detritivores ingest organic molecules found in the non-living remnants of organisms (e.g. detritus, humus)

Question 21

What are saprotrophs?

Answer 21

Saprotrophs release digestive enzymes and then absorb the external products of digestion (decomposers)

Question 22

In what two ways do autotrophs derive energy for the synthesis of organic molecules from simple inorganic substances?

Answer 22

Most autotrophs derive the energy for this process from sunlight (via photosynthesis)
Some may derive the needed energy from the oxidation of inorganic chemicals (chemosynthesis)

Question 23

Where do autotrophs gain the inorganic substances from?

Answer 23

Autotrophs obtain the simple inorganic substances required for this process from the abiotic environment

Question 24

What are examples of inorganic substances that autotrophs use?

Answer 24

These nutrients – including carbon, nitrogen, hydrogen, oxygen and phosphorus – are obtained from the air, water and soil

Question 25

Can heterotrophs also use simple organic substances from the environment?

Answer 25

YES
Heterotrophs also may obtain some simple inorganic substances from the environment, but principally obtain their carbon and nitrogen from the organic molecules produced by autotrophs

Question 26

How do heterotrophs obtain nutrients?

Answer 26

Heterotrophs obtain organic molecules from other organisms via different feeding mechanisms and different food sources

Question 27

How can heterotrophs be differentially classified from autotrophs?

Answer 27

Consequently, heterotrophs can be differentially classified according to their feeding pattern

Question 28

What are consumers?

Answer 28

Consumers are heterotrophs that feed on living organisms by ingestion

Question 29

What are herbivores?

Answer 29

Herbivores are consumers that feed principally on plant matter (e.g. cows, sheep, rabbits)

Question 30

What are carnivores?

Answer 30

Carnivores are consumers that feed principally on animal matter (e.g. crocodiles, wolves, tigers)

Question 31

What are omnivores?

Answer 31

Omnivores are consumers that have a principle diet composed of both plant and animal matter (e.g. pandas, humans)

Question 32

What are scavengers?

Answer 32

Scavengers are a type of consumer that principally feed on dead and decaying carcasses rather than hunting live prey

Question 33

What are examples of scavengers?

Answer 33

Examples of scavengers include hyenas, vultures and carrion birds (such as crows)

Question 34

What are detrivores, how do they gain their nutrients?

Answer 34

Detritivores are a type of heterotroph that obtains nutrients from non-living organic sources, such as detritus and humus

Question 35

What is detritus?

Answer 35

Detritus is dead, particulate organic matter – such as decaying organic material and fecal matter

Question 36

What does humus refer to?

Answer 36

Humus is the term given specifically to the decaying leaf litter intermixed within the topsoil

Question 37

What are examples of detrivores?

Answer 37

Detritivores include dung beetles, earthworms, woodlice, snails and crabs

Question 38

What are saprotrophs and what do they feed off of?

Answer 38

Saprotrophs live on (or in) non-living organic matter, secrete digestive enzymes into it and absorbing the products of digestion

Question 39

How are saprotrophs different from other heterotrophs?

Answer 39

Unlike other types of heterotrophs, saprotrophs do not ingest food but use enzymatic secretion to facilitate external digestion

Question 40

What is another term for saprotrophs and why?

Answer 40

Because saprotrophs facilitate the breakdown of dead organic material, they are commonly referred to as decomposers

Question 41

What are examples of saprotrophs?

Answer 41

Examples of saprotrophs include bacteria and fungi

Question 42

What are nutrients and examples?

Answer 42

Nutrients refer to the material required by an organism, and include elements such as carbon, nitrogen and phosphorus

Question 43

Why is nutrient cycling necessary?

Answer 43

The supply of inorganic nutrients on Earth is finite – new elements cannot simply be created and so are in limited supply

Question 44

How are inorganic nutrients recycled if they are finite?

Answer 44

Hence chemical elements are constantly recycled after they are used

Question 45

How do autotrophs obtain inorganic nutrients?

Answer 45

Autotrophs obtain inorganic nutrients from the air, water and soil and convert them into organic compounds

Question 46

How are inorganic compounds obtained by heterotrophs? What are the compounds used for?

Answer 46

Heterotrophs ingest these organic compounds (autotrophs) and use them for growth and respiration, releasing inorganic byproducts

Question 47

How are nutrients recycled once organisms die?

Answer 47

When organisms die, saprotrophs decompose the remains and free inorganic materials into the soil

Question 48

What does the return of inorganic nutrients to the soil ensure?

Answer 48

The return of inorganic nutrients to the soil ensures the continual supply of raw materials for the autotrophs