6 Changes in ecosystems

Question 1

Primary succession

Answer 1

When succession beguins in a virtually lifeless area where soil has not yet formed.
-caused by catastrophic events such at volcanic activity, earthquakes etc can cause the development of barren sites with no organisms inhabiting the affected area.

Question 2

Succession

Answer 2

communities change progressively over time, with one community being replaced by the next in the process of succession.
-succession occurs after natural disturbances such as tsunamis and wildfires

Question 3

r-selected species

Answer 3

A fast growing and reproducing organism which experience boom and bust fazes in population size.
They are often the first to fill a new niche. (E.g grasses, bunnies)

Question 4

K-selected species

Answer 4

A slow growing, long living species and are typically near the top of the animal food chain. (E.g elephant)

Question 5

Why is there a high level of indelicate species in Australia?

Answer 5

When the supercontinent Pangaea was separated, the island of Australia was isolated from the rest of the world. This meant unique climate and environment caused species to adapt unlike anywhere else on earth. All adaptions stayed in Australia as they couldn’t spread globally due to oceans.

Question 6

Pros and cons of prescribed burns

Answer 6

Pros
- reduces size and severity of fires
- reduces dominant species to allow others to use resources
-kills invasive species
-helps fire dependent species to germinate
-clears ground promoting new plant growth

Cons
- effects air quality
- contributes to habitat loss (E.g logs and hollows for small mammals)
- kills native individuals bringing them closer to extinction

Question 7

Pros and cons of natural bushfires

Answer 7

Pros
- reduces seed competition
- germinates seeds
- clears invasive species

Cons
- unpredictability of fires can cause fuel buildup
- larger, hotter and more intense fires
- limpact water quality

Question 8

Secondary Succession

Answer 8

is a similar process to primary succession, except that it begins at the second step with a few organisms and some organic matter and soil already present

Question 9

climax community

Answer 9

The stable community present at the final stage in succession. It’s stable as long as environmental factors remain constant.

Question 10

What is a pioneer species?

Answer 10

the species that first colonize new habitats created by disturbance.
Include fast spreading species like mosses, fungi and microorganisms.

Question 11

What is nudation?

Answer 11

The development of their size with no organisms inhabiting the affected area

Question 12

What is a fire regime?

Answer 12

The season intensity and frequency of a fire in a given area over a period of time

Question 13

Define soils

Answer 13

Alia made up of a mix of organic and inorganic particles and smaller rocks.