Topic 5: On the wild side Flashcards
Definition of an ecosystem
All the organisms living in a particular area + Abiotic (non-living) factors
Definition of a niche
The role and organism plays in an environment at a certain point in time. No two species can occupy the same niche but they cant compete for it
Definition of a community
All of the organisms OF A PARTICULAR SPECIES living in a particular habitat at a time
Definition of a habitat
The place where an organism lives
Definition of a population
All of the organisms of one species in a habitat
Examples of Abiotic factors
Light
Oxygen
Moisture levels
Temperature
Examples of biotic factors
Predators
Food availability
Parasitism
Disease
Definition of distribution
Definition of Abundance
Distribution = How spread out everything is
Abundance = Number of something
Difference between primary and secondary succession
In primary succession, the pioneer species is less complex and starts with nothing where as in secondary succession the pioneer species is more complex and already has nutrients in the soil
Explain the process of succession
- The area is first colonised by the pioneer species e.g. lichens which are adapted to survive in harsh conditions
- As organisms die, they are decomposed by microorganisms, thus adding humus (the organic component of soil). This leads to the formation of soil, which makes the environment more suitable for more complex organisms
- As more organisms are decomposed overtime, the soil becomes richer in minerals, thus enabling larger, more varied and more productive plants such as shrubs to survive.
- -Eventually, a climax community is established - the most productive, self-sustaining and stable community of organisms the environment can support, usually with only one or two species.
Outline cyclic phosphorylation
- Photon hits chlorophyll in photosystem I (PSI).
- Electrons are excited.
- Electrons taken up by an electron acceptor.
- Electrons pass along an electron transport chain. Energy is released, and ATP is synthesised.
- Returns to chlorophyll in PSI.
Outline non-cyclic phosphorylation
- Photon hits chlorophyll in photosystem II (PSII).
- Electrons are excited.
- An electron acceptor takes up electrons and passes along an electron transport chain to PSI. Energy is released, ATP is synthesised.
- Photolysis: light energy breaks apart the strong bonds in water molecules - forming hydrogen and hydroxide ions. Electrons released replace lost electrons in the chlorophyll of PSII. Hydroxide ions react together to form water and oxygen.
- Photon hits chlorophyll in Photosystem I.
- Electrons are excited.
- Electrons are taken up by an electron acceptor and passed along an electron transport chain to NADP.
- NADP takes up an H+ ion from dissociated water and forms reduced NADP.
Definition of evolution
Evolution is a change in the heritable traits of biological populations over successive generations. It occurs as a result of a change in allele frequency which in turn is affected by changing selection pressures.
Outline the process of evolution via natural selection
- A variety of phenotypes exist within a population due to random mutation.
- An environmental change occurs and as a result of the selection pressure changes
- Some individuals possess advantageous alleles which give them a selective advantage and allow them to survive and reproduce.
- The advantageous alleles are passed on to their offspring.
- Overtime, the frequency of alleles in a population changes.
Where do the light-independent reactions take place?
Where do the light-dependent reactions take place?
Light-independent = Stroma
Light-dependent = Thylakoid membrane