Life Processes In The Biosphere

Question 1

What is the actual size of a population controlled by? (3)

Answer 1

Births
Deaths
Movements in and out area

Question 2

What is the number of births controlled by?

Answer 2

The natural reproductive potential of a species (biotic potential)

Question 3

What is the number of deaths controlled by?

Answer 3

Environmental factors

Question 4

Give examples for density independent factors? (3)

Answer 4

Drought
Good
Volcanic eruption

Question 5

Give examples of density dependent factors (2)

Answer 5

Food supply

Disease

Question 6

What is the carrying capacity?

Answer 6

The max population size that can be supported indefinitely without damaging or over-exploiting the environment

Question 7

What happens if the population drops below that carrying capacity?

Answer 7

The density dependent factors become weaker so mortality decreases and the population increases

Question 8

What does higher diversity in less abiotically extreme environments result in?

Answer 8

More stable ecosystems in which populations are dominated by biotic factors

Question 9

What are the abiotic factors that affect the survival of a species? (5)

Answer 9

Temperature
Light
pH
Water 
Mineral Nutrients

Question 10

What are the biotic factors that affect the survival of a species? (7)

Answer 10

Feeding
Predators
Symbiotic Nutrition
Pollination 
Seed Dispersal
Disease
Nutrient Supply

Question 11

What is Taxonomy?

Answer 11

The study of how organisms can be group according to how closely related they are

Question 12

Define Species

Answer 12

A group of organisms that resemble one another more closely than members from other groups

Question 13

Define Population

Answer 13

Refers to the individuals of a species living in a particular area

Question 14

Define Community

Answer 14

The populations of all the species of plants and animals living in a particular area

Question 15

Define Ecosystem

Answer 15

The community of organisms living in an area and their inter-relationships with the environment

Question 16

Define Habitat

Answer 16

Place where species, organisms or population lives

Question 17

Define Niche

Answer 17

The role a species plays in its habitat

Question 18

Define Biome

Answer 18

Large geographical region with particular climatic features

Question 19

Define Biosphere

Answer 19

Part of the planet that is inhabited by living organisms

Question 20

What is the climax community usually controlled by?

Answer 20

The climate (climatic climax)

Question 21

What is the sequence of changing communities called?

Answer 21

A sere

Question 22

How long does primary succession continue for?

Answer 22

Until the climax community develops

Question 23

What do species that colonise an area change? What does this lead to?

Answer 23

Change abiotic factors and lead to not favourable conditions, which allow new species to colonise and out-compete others

Question 24

As abiotic conditions get less extreme, what happens to the diversity of species?

Answer 24

It increases

Question 25

What is a hydrosere?

Answer 25

A succession that begins in water

Question 26

What is the first step of a hydrosere?

Answer 26

An area of freshwater us colonised by single celled algae from soil

Question 27

In a hydrosere, what happens when plants begin to grow?

Answer 27

Water becomes shallower and shade of emergent plants kills submerged plants

Question 28

In a hydrosere, what happens when the lake starts to fill up with sediment?

Answer 28

Aquatic species disappear and trees starts to colonise

Question 29

In a hydrosere, how does the soil become drier? What eventually colonises?

Answer 29

More sediments fill in and transpiration by trees removes the water. Oak colonise

Question 30

What do denser canopies provide? What's a consequence of this?

Answer 30

Provides shade so smaller plants grow less well

Question 31

What does the speed with which a species colonises depend on?

Answer 31

The with which they can travel

Question 32

What is a Lithosere?

Answer 32

The development of the a community on bare rock

Question 33

What are the early abiotic conditions like in a lithosere? (4)

Answer 33

Very harsh No soil Lack of water Extremes of temperature

Question 34

What are the first colonisers of a Lithosere called?

Answer 34

Simple Autotrophs (algae and lichens)

Question 35

What happens in the first stage of Lithosere succession?

Answer 35

Weathered rock fragments and DOM start building up and mosses colonise

Question 36

What happens when the soil builds up in a Lithosere?

Answer 36

Plants get larger and abiotic conditions become less extreme

Question 37

What happens when larger plants colonise in a Lithosere?

Answer 37

Seedlings of less hardy plants survive under their shade

Question 38

What happens when the soil is deep enough in a Lithosere?

Answer 38

The Edaphic factors (soil factors) are suitable and trees can colonise

Question 39

What do the the first trees of a Lithosere usually have?

Answer 39

Wind-blown seeds

Question 40

What do areas that have water available all year usually become?

Answer 40

Woodland (temperature controls which type)

Question 41

What do areas with seasonal rain usually become?

Answer 41

Grassland

Question 42

What is secondary succession?

Answer 42

The changes that occur in an area that had already reached the climax state

Question 43

What events interrupt succession and can remove the climax community?

Answer 43

``` Natural events (forest fires, hurricanes) Human activities (deforestion, grazing, mowing and burning) ```

Question 44

What are Plagioclimaxes?

Answer 44

If the human activities that destroyed the climax community continue, a new community of species will develop

Question 45

What happens if the human activity that produced a Plagioclimax stops?

Answer 45

Secondary succession will eventually re-establish the climax community

Question 46

What happens if the Plagioclimax community is considered important?

Answer 46

It is necessary to continue the activities that maintained the Plagioclimax

Question 47

In the UK, what does conservation often involve?

Answer 47

Management of plagioclimaxes and the continuance of previous activities

Question 48

Why might culling of a population be necessary?

Answer 48

To conserve species or habitats where natural control mechanisms no longer exist

Question 49

What is Sigmoidal Population Growth?

Answer 49

The growth pattern of a population where abundant resources slow rapid growth followed by population stabilisation as the carrying capacity is reached