Practise IB ESS SL 2.1 by identifying species and interactions, designing sampling methods and explaining how resources and feedback shape populations.
Define the term species.
Figure:Aquatic organism image A
Figure:Aquatic organism image B
Figure:Aquatic organism image C
Figure:Aquatic organism image D
The organisms shown below (not drawn to scale) were found in an aquatic ecosystem.
Aquatic-organism context: use the four organisms shown in the protected the four aquatic organisms shown above visual when constructing or evaluating an identification key.
Suggest two visible characteristics of the organisms shown above which could be used to construct an identification key.
Aquatic-organism context: use the four organisms shown in the protected the four aquatic organisms shown above visual when constructing or evaluating an identification key.
Identify one limitation of using a key to identify an organism.
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.