4.1 Species, communities and ecosystems

Question 1

What is a species?

Answer 1

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

Question 2

What happens when two different species breed?

Answer 2

Normally unable to produce offspring. If they are produced they are usually infertile

Question 3

What is a population?

Answer 3

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

Question 4

What happens to organisms from the same species that live in different regions?

Answer 4

They are reproductively isolated and unlikely to interbreed but it is still functionally possible

Question 5

What is a community?

Answer 5

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

Question 6

What is a habitat?

Answer 6

The environment where a species normally lives
or the location of a living organism

Question 6

What is an ecosystem?

Answer 6

A community and its abiotic environment

Question 7

What is ecology?

Answer 7

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

Question 8

What are the two ways living organisms can obtain chemical energy?

Answer 8

Autotrophs and heterotrophs

Question 9

What is an autotroph?

Answer 9

Synthesises its own organic molecule from simple inorganic substances

Question 10

How is energy for autotrophs derived?

Answer 10

Via sunlight or the oxidation of inorganic molecules

Question 11

Why are autotrophs often referred to as producers?

Answer 11

Because they synthesise their own organic molecules

Question 12

What are heterotrophs?

Answer 12

Obtains organic molecules from other organisms dead and alive

Question 13

Why are heterotrophs called cinsumers?

Answer 13

As they cannot produce their own organic molecules and thus obtain it from other sources

Question 14

What is it called when a unicellular organism can use both form of nutritions of heterotrophs and autotrophs?

Answer 14

Mixotrophs

Question 15

How can species be classified in accordance to?

Answer 15

Their mode of nutrition

Question 16

What are the three methods of heterotrophs?

Answer 16

Consumers
Detritivores
Saprotrophs

Question 17

What do detritivores do?

Answer 17

Ingest nonliving organic molecules

Question 18

What do saprotrophs do?

Answer 18

Release digestive enzymes and absorb the external products of digestion

Question 19

What are the two ways autotrophs derive energy?

Answer 19

Photosynthesis and chemosynthesis

Question 20

What is chemosynthesis?

Answer 20

Energy derived from the oxidation of inorganic chemicals

Question 21

Where do autotrophs obtain their inorganic substances from?

Answer 21

The abiotic environment

Question 22

Where are the nutrients autotrophs needed from?

Answer 22

Air, water and soil

Question 23

What are herbivores?

Answer 23

Consumers that feed principally on plant matter

Question 24

What are carnivores?

Answer 24

Consumers that feed principally on animal matter

Question 25

What are omnivores?

Answer 25

Consumers that feed on both plant and animal matter

Question 26

What are scavengers?

Answer 26

Type of consumer that principally feed on dead and decaying carcasses rather than hunting live prey

Question 27

What is detritus?

Answer 27

Dead, particulate organic matter

Question 28

What is humus?

Answer 28

The decaying leaf litter intermixed within the topsoil

Question 29

Where do saprotrophs live?

Answer 29

In or on non living organic matter

Question 30

Do saprotrophs ingest food?

Answer 30

No they do external digestion

Question 31

What are nutrients?

Answer 31

Material required by an organism

Question 32

What word is used to describe the supply of inorganic nutrients on earth?

Answer 32

Finite

Question 33

Why are inorganic nutrients finite?

Answer 33

As new elements cannot simply be created and are in limited supply

Question 34

What is the chain of nutrient cycling?

Answer 34

Autotrophs to Heterotrophs to Saprotrophs back to autotrophs

Question 35

What does autotrophs convert inorganic nutrients into?

Answer 35

Organic compounds

Question 36

What do heterotrophs use the organic compounds for?

Answer 36

Growth and respiration

Question 37

What happens as heterotrophs use organic compounds?

Answer 37

Inorganic byproducts are released

Question 38

What happens when an organism dies?

Answer 38

Saprotrophs decompose the remains and free inorganic materials into the soil

Question 39

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

Answer 39

The continual supply of raw materials for the autotrophs

Question 40

What do ecosystems describe?

Answer 40

The interaction between biotic and abiotic components

Question 41

What are the three main components required for sustainability in an ecosystem?

Answer 41

Energy availability Nutrient availability Recycling of wastes

Question 42

What is energy availability?

Answer 42

Light from the sun provides the initial energy source for almost all communities

Question 43

What is nutrient availability?

Answer 43

Saprotrophic decomposers ensure the constant recycling of inorganic nutrients within an environment

Question 44

What is the recycling of wastes?

Answer 44

Certain bacteria can detoxify harmful waste byproducts

Question 45

What are mesocosms?

Answer 45

Enclosed environments that allow a small part of a natural environment to be observed under controlled conditions

Question 46

What is a terrarium?

Answer 46

A small transparent container where plants or animals are kept and observed

Question 47

What are the three main steps to create a self sustaining terrarium?

Answer 47

Building a verdant foundation Selecting the right plants Maintaining appropriate conditions

Question 48

What will the presence of two species within a given environment be dependent on?

Answer 48

Potential interactions between them

Question 49

If two species are typically found within the same habitat what will they show?

Answer 49

A positive association

Question 50

If two species tend not to occur within the same habitat what will they show?

Answer 50

A negative association

Question 51

When will species typically show negative association?

Answer 51

If there is competition for the same resources

Question 52

What is competitive exclusion?

Answer 52

When one species utilises the resources more efficiently precluding survival of the other species

Question 53

What is resource partitioning?

Answer 53

When both species may alter their use of the environment to avoid direct competition

Question 54

What happens if two species do not interact?

Answer 54

There will be no association and their distribution is independent of each other

Question 55

What is a way that the presence of two species in a given environment can be determined?

Answer 55

Using quadrat sampling

Question 56

What is a quadrat?

Answer 56

A rectangular frame of known dimensions that is used to establish population densities

Question 57

What are the two ways quadrats can be distrubuted?

Answer 57

Randomly or in a pattern

Question 58

What are the two ways species can be counted?

Answer 58

Counted or estimated via percentage cover

Question 59

What is quadrat sampling not an effective method for?

Answer 59

Motile organisms

Question 60

What is a chi squared test?

Answer 60

A test to test the data to determine if there is a statistically significant association between the distribution of two species?

Question 61

What are the five steps for completing a chi squared test?

Answer 61

1. identify hypotheses 2. construct a table of observed vs expected frequencies 3/ apply the chi square formuls 4. determine the degree of freedom 5. identify the p value

Question 62

What is a null hypothesis?

Answer 62

No significant difference

Question 63

What is an alternative hypothesis?

Answer 63

There is a significant differences

Question 64

How do you calculate expected frequencies?

Answer 64

(row total x column total) / grand total

Question 65

What is the chi squared formula?

Answer 65

x2= sum of (O-E)2 / E

Question 66

How do you calculate degrees of freedom?

Answer 66

df = (m-1)(n-1) m = rows n = columns

Question 67

When is a value considered significant?

Answer 67

If there is less than a 5% probability