What is the relationship between different living organisms? This IBDP Biology blog post is a introduction to Topic 4, Ecology. We will look at:
- What population is
- What an ecosystem is
- The differences between consumers, detrivores and saprotrophs
Ecology
Species: Groups of organisms that can potentietally interbreed to produce fertile offspring
If species are not closely related it is usually impossible for individuals of different species to interbreed
If individuals of different species interbreed and produce offspring - Hybrids will be sterile [infertile don't produce sex cells because the chromosomes of parents from different species don't match]
Population
Population: A group of organisms of the same species living in the same area at the same time
Organisms of the SAME species are SEPARATED geographically and are UNLIKELY to breed but the ability to do so remains. The seperated organisms are part of different populations
U2: Members of a species may be reproductively isolated in seperate populations
Example: South Africans within SA and South Africans in Egypt
Community
Community: Group of populations of different species living together and interacting with each other in the same area
All organisms are dependent on interactions with members of other species for survival this includes plants and microbes
Example: Lions depend Zebras or Bucks
Finding Nemo fishbowl
Ecosystems
Ecosystem: A community forms an ecosystem by its interactions with the abiotic environment
Biotic: Living eg, [preys and predators]
Abiotic: Non-living surroundings of a community [soil, air, water]
Ecosystem = Community + Abiotic Environment
Consumers
Consumers: Heterotrophs that feed on organisms by ingestion to obtain their organic molecules
Ingestion: The taking in of a substance
Consumers can be classified as:
- Herbivores-
feed on Producers
Example: Zebras, Deer and Asphids
- Carnivores-
feed on other Consumers
Example: Lions, Snakes and Ladybirds
- Omnivores-
feed on both Producers and Consumers
Example: Chimpanzee and Mice
- Scavengers-
specialized carnivores that feed mostly on dead and decaying animals
Example: Hyenas, Vultures and Crows
Detrivores
Detrivores: Heterotrophs that obtain organic nutrients from non-living organic sources such as detrius and humus by internal digestion
Detrius: Dead material from living organisms [dead leaves, parts of decomposing animals and feces]
Humus: Decaying leaf litter mixed with soil
Example: Dung beetles, Earthworms, Woodlice and Crabs
Saprotrophs
Saprotrophs: Heterotrophs that obtain organic nutrients from dead organisms by external digestion
- Saprotrophs live on or live in non-living organic matter.
- Secrete digestive enzymes into the organic matter [dead leaves, dead animals, wood]
- Absorb the needed substances/products of digestion
- Proteins, Carbs, Lipids are digested externally and absorbed
NOT Consumers - do not ingest the food
External digestion - digestive enzymes are secreted
Decomposers - breakdown organic material
Example: Bateria and Fungi
And that's the end of part 1!
References:
https://www.google.com/url?sa=i&url=http%3A%2F%2Fib.bioninja.com.au%2Fstandard-level%2Ftopic-4-ecology%2F41-species-communities-and%2Fheterotrophs.html&psig=AOvVaw2eMKnV3LfFht8ltu_PJYZb&ust=1625627503655000&source=images&cd=vfe&ved=0CAsQjhxqFwoTCLio08G8zfECFQAAAAAdAAAAABAS
Drafted by Venetia (Biology)