Biodiversity and Ecosystems Flashcards
1
Q
On a graph, when population of a species palteaus:
A
- species has reached carrying capacity
- due to intraspecific competition
1
Q
Why is …. an example of succession? (3)
A
- orgnanism changes the environment
- creates new niches
- allows different species to be successful
2
Q
what is a niche
A
a role of an organism in an ecosystem
3
Q
what is meant by the competitive exlusion principle? (2)
A
- the fact that no 2 species can occupy exactly the same niche
- if 2 species use exactly the same niche then one species will always outcompete the other.
4
Q
Define succession (1)
A
The change in the species present over time.
5
Q
What is lichen? What makes it a good pioneer species? (4)
A
- Symbiotic mutualistic relationship between a fungi and an algae
- fungi is able to absorb mineral ions from rocks and provide them to the algae.
- The algae is able to photosynthesize, so create its own organic molecules
5
Q
What key features does a pioneer species usually have? (4)
A
- Seeds or spores, can disperse long distances
- low nutrients requirement,
- shallow roots
- quick growing.
6
Q
5
why are new species able to colonise as succession progresses?
A
- As other species change the abiotic and biotic conditions
- so that new niches are created,
- allowing new species to colonise.
7
Q
Give 2 features of a climax community: (2)
A
- same species present (over long time)
- abiotic factors more constant overtime
- populations stable
8
Q
Relationship between the alga and the fungus allows the light and survive on an inorganic surface such as a wall. (2)
A
- alga photosynthesise
- fungus anchors lichen
9
Q
Describe how giving this vaccine leads to production of antibody against HPV (4)
A
- vaccine contains antigens of HPV
- displayed on APC
- specific helper T cells stimulate specific B cell
- B plasma from B cell mitosis
- B plasma produces antibody
10
Q
A
