Lecture notes
chapter 23 ecosystems
- Institution
- OCR
chapter 23 ecosystems biology OCR A notes Alevels
[Show more]
Seller
Follow
Content preview
2323.1 - factors affecting an ecosystem
Ecosystem = all interacting living organisms and non living factors within an area
Biotic Abiotic
= living organisms = non living things in ecosystem
3 factors: 6 factors:
1) Competition = in area with 1) Light = required for
different organisms , they would be
photosynthesis → affect plant
competing for same food/space/
mate growth
- 2 types of competition: 2) Water availability =
intraspecific (between same photosynthesis
species) + interspecific (between 3) 02 availability = needed for
diff species) aerobic respiration
2) Predation = when predator 4) Temp = can affect enzymes in
hunting prey → impact
body → denaturation / or can
population size
3) Diseases = biotic as diseases trigger migration which can
caused by pathogens aka change population size in diff
microorganisms →can affect areas
pop size Adaphic (soil) factors
5) Soil ph = diff plants prefer diff
ph levels
6) type of soil (certain types of soil
are better at retaining water
which is good however there are
some soil that are so good at
retaining water such as
waterlogged soil which refers to
soil that has water filling up all
the air spaces , reducing oxygen
availability to the roots
Examples of soil types
- Clay = has fine particles →
easily waterlogged and forms
clumps when wet
- Loam = diff sized particles →
retains water but doesn't become
waterlogged (mix of clay + sand)
, - sandy= course well separated
particles that allow free draining -
sandy soil does not retain water
and is easily eroded
23.2 - trophic levels and biomass
1/03/23
Trophic levels
= stages in the food chain
- Producers = plants that produce food in first place by photosynthesis to make
glucose (first trophic level) e.g. algae
- Primary consumers = eat producers , usually herbivores (some of energy
transferred to PC)
- Secondary consumers = eat primary consumers (usually is carnivore but can
be herbivore)
- Tertiary consumers = eat secondary consumers
- Producer would be a plant but other examples chemoautotrophic = bacteria that
can generate own bacteria
- Carnivore = eat only other animals
- Herbivore = eat only plants
- Omnivore = eat both plant + animal
Producers → primary consumers →secondary consumers → tertiary
- Food chain can be represented by pyramid which represents the number of
organisms at each of the trophic levels ALSO can show the biomass of each
level
Biomass
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller jenishasuresh. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £2.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
72349 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now