Species and communities 4.1

Ecology is the study of the interconnections between living organisms and their environment. There is such a complex network of links in any location that ecologists have to break down and classify these relationships whether they be feeding, competition or reproduction. This topic is an introduction to these divisions.

Key concepts

Learn and test your biological vocabulary for 4.1 Species and communities using these flashcards 

Essentials

These slides summarise the essential understanding and skills in this topic. 
They contain short explanations in text and images - good revision for all students.

Read the slides and look up any words or details you find difficult to understand.

Summary

Summary list for topic 4.1 Species and communities

  • Species are "groups of organisms that can potentially interbreed to produce fertile offspring".
  • Members of a species may be reproductively isolated in separate populations.
  • Species can be autotrophic or heterotrophic in nutrition (a few species are both).
  • Consumers are heterotrophs that feed on living organisms by ingestion.
  • Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion.
  • Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion.
  • A community is "populations of different species living together and interacting with each other."
  • An ecosystem is "a community and its interactions with the abiotic environment."
  • Autotrophs obtain inorganic nutrients from the abiotic environment.
  • The supply of inorganic nutrients is maintained by nutrient cycling.
  • Ecosystems have the potential to be sustainable over long periods of time

Skills (can you ....)

  • Classify species as autotrophs, consumers, detritivores or saprotrophs from a knowledge of their mode of nutrition.
  • Set up sealed mesocosms to try to establish sustainability. (Practical 5)
    Mesocosms in sealed glass vessels are preferable because entry and exit of matter can be prevented but light can enter and heat can leave. Aquatic systems are likely to be more successful than terrestrial ones.
  • Test for association between two species using the chi-squared test with data obtained by quadrat sampling.
    For example An ecosystem chosen where varying factors affect the distribution of the chosen species. Random quadrat sampling should be used to measure the presence or absence of the chosen species.

Mindmaps

These diagram summaries cover the main sections of topic 4.1 Species and communities
Study them and draw your own list or concept map from memory.

Exam style questions

This question requires knowledge of the different methods organisms use to gain energy.

Compare and contrast the sources of energy and organic nutrients of consumers, detritivores and saprotrophs.  (4 marks)
 

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Click the + symbol to show the model answer

Extra exam question on sustainability in ecosystems    - - - Click the + to open it -- >

This question requires knowledge of sustainability in ecosystems.
Answer the question below on paper and then check your answer with the model answer.

Question:  Discuss the importance of sustainability in an ecosystem (6 marks)







Examiner hints- Discuss means offer a considered and balanced review that includes a range of arguments, factors or hypotheses. Opinions or conclusions should be presented clearly and supported by
appropriate evidence.

In ecology responses, use scientific terminology precisely.

Click the + symbol to show the model answer 

Test yourself

This is a self marking quiz containing questions covering the topic outlined above.
Try the questions to check your understanding.


START QUIZ!

Drag and drop activities

Test your ability to construct biological explanations using the drag and drop questions below.

The components of an ecosystem and their interactions are an important part of this topic.

Drag and drop the correct word to define the components of an ecosytem.

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abiotic living populations independent feeding sustainable non-living interreacting biotic

A community is a naturally occurring group of inhabiting a particular environment and interacting with each other (for example by relationships), and relatively of other groups.

An ecosystem is a community of organisms and their environment.

The abiotic component of an ecosystem is the element of an ecosystem.

The component of an ecosystem is the community of an ecosystem.

Examiner hint: Use the correct terminology in responding to questions on ecology.


 

Click the '+' symbol to open the next explanation.

Extra drag and drop explanation on the biotic components of an ecosystem,  click to open.

The biotic components of an ecosystem are the living organisms

Drag and drop the correct term into the gap to outline the feeding methods of the community in an ecosystem.

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first ingestion organic light second internal endocytosis exocytosis all inorganic Heterotrophs external

Autotrophs (Primary producers) manufactures compounds from using energy. They are found at the trophic level, the basis of the food chain.

are consumers that feed on the organic compounds of living organisms by . They are found at levels of the food chain except the first.

Detritivores obtain organic nutrients from detritus by digestion.

Saprotrophs obtain organic nutrients from dead organisms by external digestion using of enzymes.

The ways in which organisms in an ecosystem obtain energy need to be understood.


Just for fun

Everyone needs a bit of fun while they revise. Try this Species and communities wordshoot revision game.
Can you reach the leader board?