Enviromental Studies - Grade 12 W/S (pg. 1 - 24)

Question 1

What is Ecology?

Answer 1

Study of interactions of organisms with their physical & biological environment.

Question 2

Population

Answer 2

Individuals living together.

Group of organisms of same species that occupy same area & breed freely.

Question 3

Community

Answer 3

Different populations together.

Group of diff. species that inhabit & interact in a particular area.

Question 4

Ecosystem

Answer 4

Community & non-living things in surroundings.

Group of different species of organisms that interact with each other & environment.

Question 5

Biosphere

Answer 5

All ecosystems on Earth.

Part of earth where living organisms found.

Question 6

Organism

Answer 6

Individual form of life composed of a single cell / complex of cells capable of growing & reproducing.

Question 7

Species

Answer 7

Group of closely related organisms that usually can interbreed & produce fertile offspring.

Question 8

Individuals

Answer 8

Single organism capable of independent existence.

Question 9

What effects size of population?

Answer 9

• Natality (birth rate)
• Mortality (death rate)
• Immigration
• Emigration

Question 10

What is a closed population?

Answer 10

No immigrations / emigrations.

Question 11

What is Carrying Capacity?

Answer 11

Size at which a balance is reached in a population & it stabilises.

Question 12

What are the density Independent limiting factors?

Answer 12

• Physical factors (rainfall, temp. etc.)
• Catastrophic events (flood, fire etc.)

Question 13

What are the density dependant limiting factors?

Answer 13

> Compete more for resources
Easier found by predators
Spread disease & parasites more readily

Question 14

Census

Answer 14

Counting every individual in a population.

Question 15

On what type of individuals is the direct method used?

Answer 15

• Slow moving
• Stationary
• Stay in fixed position (usually)

Question 16

Predation

Answer 16

Biological interaction where 1 species, predator, hunts, kills & eats another species, prey.

Question 17

How do predators help create & maintain greater diversity within an ecosystem?

Answer 17

—> Regulate abundance
—> Increase biodiversity
—> keep prey population genetically fit
—> provide vital food sources for scavengers

Question 18

Food web

Answer 18

Interconnected set of all food chains in an ecosystem.

Question 19

Competition

Answer 19

When 2/more individuals compete for the same resource that are in short supply.

Question 20

Intraspecific Competition

Answer 20

Between individuals of same species.
(Most intense competition)

Question 21

Interspecific Competition

Answer 21

Between individuals of different species.
(Where niches of habitat are similar)

Question 22

Ecological Niches

Answer 22

All conditions necessary for an organism to survive and reproduce.

Question 23

For population to survive they must reproduce by

Answer 23

• Tolerating physical environment
• obtain energy & nutrients
• Cope with competition
• Avoid predators

Question 24

Specialisation

Answer 24

Structural & behavioural adaptations enabling individuals of diff. species to co-exist.

Question 25

What is Competitice Exclusion?

Answer 25

1 of 2 competing species is more successful than the other. (Successful survive & others disappears)

Question 26

What is Competitive Co-existence?

Answer 26

2 competing species co-exist in same habitat. (Overlapping niches, but they use resource slightly different = resource partitioning)

Question 27

Resource Partitioning

Answer 27

Process whereby species with similar requirements living in same habitat, evolve specialised traits.

Question 28

How resources partitioned?

Answer 28

Used: - At diff. Times - In diff. Areas of habitat - In diff. Parts of same plant

Question 29

Stratification

Answer 29

Vertical structure dividing vegetation into layers, created by diff. trees & other plants of varying size & species.

Question 30

Ecological Succession

Answer 30

Predictable pattern of gradual change over time in the types of species in a community following a disturbance.

Question 31

Primary Succession

Answer 31

On sight NOT previously had plants growing on them.

Question 32

Secondary Succession

Answer 32

On sight where DISTURBANCE removes some / all species but soil remains.

Question 33

What is the community structure determined by?

Answer 33

1. Disturbances - Physical - Human / animal - Climate change 2. Competitive Interaction

Question 34

What are the stages of succession?

Answer 34

1. Pioneer Species Stage (Bare ground favour pioneer plant species) 2. Intermediate Species Stage (More structurally complex) 3. Climax Community (Semi-stable)

Question 35

What are the features of the pioneer plant species?

Answer 35

- Hardy (withstand extreme temp. & moisture variation) - Establish Rapidly - Spores & seeds disperse long distances - Not grow in shade - Prepare surroundings for later colonists - Build-up stabilise & enrich soil - Alter amount of light by providing shade

Question 36

What determines an endpoint of a community?

Answer 36

> Rainfall > Overgrazing > Draining of wetlands > Climate change > Invasion of alien plants

Question 37

Social Organisations

Answer 37

Structure of relationships within a group. ( Improves survival & reproductive success of an individual)

Question 38

Social organisations makes it easier to:

Answer 38

— Avoid predator attacks — Find food — Divide labour — Find mates — Protect resources — Regulate population size

Question 39

Herds increase safety of group bc :

Answer 39

> Group more watchful > Mob predator > Dilution effect > Confuse & Distract > Flock protect > inexperience given guidance & protect.

Question 40

Eusocial Animals

Answer 40

Most advanced form of social organisation.

Question 41

Factors that cause change in make-up of pop.

Answer 41

~ HIV / AIDS ~ Young immigrants / emigrants ~ Men fighting wars ~ Reduced birthrates

Question 42

Ecological Footprint

Answer 42

Measure of human demand on earth’s ecosystem.

Question 43

Bio capacity

Answer 43

Amount of productive land & water available to produce resources we use & absorb the waste we produce.