Practise IB ESS HL 2.1 by evaluating sampling design, limiting factors, feedback and resilience across interacting populations and communities.
Define the term species.
Crested Newt (Triturus cristatus)
Avocet (Recurvirostra avosetta)
Bithynia (Bithynia tentaculata)
The four species shown in the wetland species images shown above can be found in wetland ecosystems.
newt\#/media/File:Kammmolchmaennchen.jpg, by Rainer Theuer]
media/File:Bithynia_tentaculata.jpg, by Michal Maňas]
Table:Classification key for four wetland species
Construct a classification key to identify these animals by entering appropriate contrasting features and the names of the organisms to complete the table below:
State one limitation of using a key to identify organisms.
Figure:Avocets in a wetland ecosystem
Avocets, seen in the Lake Shergar map shown above, often gather in large populations of up to a few thousand birds before migrating.
Describe a method to estimate the size of an avocet population.
Oystercatchers and avocets both feed on small animals in the mud of the wetlands. State the most likely relationship between these two species.
Figure:Some trees found in the forests of California
Using Figure: Some trees found in the forests of California and the identification key below, identify species A and species B.
Figure:Giant sequoia cones containing seeds
Figure:Long-horned beetle
With reference to Figures: Giant sequoia cones containing seeds and Long-horned beetle, state the species interaction between the giant sequoia (Sequoiadendron giganteum) and the long-horned beetle (Phymatodes nitidus).
Figure:Habitat preference of Danube fish species
Figure: Habitat preference of Danube fish species
identify the preferred habitat of bream.
compare and contrast the abiotic factors found in the straight part of the river with the abiotic factors found in the meandering part of the river.
| Years | Average sediment flow / tons yr^{-1} |
|---|---|
| 1921-1960 | 67.5 |
| 1971-1980 | 41.3 |
| 1981-1990 | 29.2 |
Table:Changes to sediment flow into the delta
Table: Changes to sediment flow into the delta: Sediment-flow and Danube-delta maintenance context
Table: Changes to sediment flow into the delta data
• 1921–1960 — average sediment flow: 67.5 tons yr⁻¹.
• 1971–1980 — average sediment flow: 41.3 tons yr⁻¹.
• 1981–1990 — average sediment flow: 29.2 tons yr⁻¹.
The Danube River delta is where the Danube flows into the Black Sea and includes UNESCO Biosphere Reserves and a World Natural Heritage site.
A delta is formed by continuous deposition of sediment carried by the river; sediment adds height and helps it extend into the sea.
The delta is a wetland ecosystem rich in plants, birds and fish, including over 1000 plant species, 300 bird species and endangered sturgeon.
Moldova takes nearly 20% of its water supply requirements from a branch of the Danube.
Suggest what effect this change in the sediment flow would have on the maintenance of the Danube River delta.
FigureA:Number of fish species breeding by month
FigureB:River discharge by month in the Danube River delta
Using Figures A and B: Number of fish species breeding by month and River discharge by month in the Danube River delta, outline the relationship between the number of fish species breeding and river discharge.