Ecosystems

1. Ecosystems

2. Ecosystems • Ecology is the study of Ecosystems • Ecosystems consist of both biological and physical factors interacting, known as biotic and abiotic factors. • Examples of ecosystems – marine, alpine, desert • Ecosystems are largely self-sustaining - they can continue into the future largely without inputs from outside the system. • Ecosystems are the most complex level of biological organisation. • Biomes are broad categories of ecosystems on a world-wide scale. Biomes are classified largely on climate.

3. Biotic Factors • A COMMUNITY is the biological part of an ecosystem, and consists of all the different populations of species living in one place at a time. • A POPULATION is all the individuals of one particular species living in the same area at the same time. • DIVERSITY – the richness or number of different species present. – the relative distribution (evenness) of abundance of species.

4. Habitat • Habitat is a the type of place where and organism lives. • Example – a water lily in a pond • Example – you in a house • Organisms can be limited to one habitat or have a range of habitats • Microhabitats are smaller localised areas within a habitat. • Example – your bedroom in your house • Example- moss on a tree trunk in a forest

5. Niche • The role of a species within its community • The way of life of an organism • Where an organism lives, feeds, what it eats, when it eats, conditions it can tolerate • Where a species survives – it’s status in its habitat • Different features allow species to occupy different niches

6. Ecological Communities • Littoral Zone – Biology Camp

7. Open Forest – Toolangi State Forest

8. Mallee Ecosystem

9. Ecological Groups • Living communities in the 3 different ecosystems mentioned previously, contain very different species. • BUT - There is a common pattern to each community. • Members of every community can be identified as belonging to one of the following ecological groups: • producers or autotrophs • consumers or heterotrophs • decomposers.

10. Producers/Autotrophs • Members of an ecological community that manufacture organic compounds (glucose=chemical energy) from simple inorganic compounds (carbon dioxide), using an abiotic energy source (sunlight). • Make chemical energy available for both their own use and use by all other community members of that ecosystem. PHOTOSYNTHESIS

11. Examples of Producers NB: CYANOBACTERIA (BLUE-GREEN ALGAE) ARE ALSO PRODUCERS

12. CONSUMERS/HETEROTROPHS • Obtain energy by eating other organisms • All animals – divided into four sub-groups: • HERBIVORES – EAT PLANTS eg. Caterpillars and koalas • CARNIVORES – EAT ANIMALS eg. Snakes, numbats and lions • OMNIVORES – EAT PLANTS AND ANIMALS eg. Humans and crows • DETRITIVORES – EAT DECOMPOSING MATTER (detritus) eg. Earthworms, dung beetles and crabs. NB: Detritivores are different to DECOMPOSERS

13. DECOMPOSERS • Release enzymes to break down organic matter outside their bodies and then absorb some of the broken down products as their source of chemical energy. • Examples of broken down matter not absorbed by decomposers are Nitrates, Phosphates and other important mineral nutrients which are taken up by producers. • Eg. Various species of fungi and bacteria

14. Interactions Within Ecosystems • Occur all the time between living things (biotic) and their physical environment (abiotic), in every ecosystem. • Tolerance range for abiotic factors determines an organisms ability to survive. • Interactions occur within abiotic surroundings – eg large storms can change the physical landscape and the pH of soil and water.

15. Ecological Interactions between organisms (biotic) and their environment (abiotic and biotic)

16. Types of Interactions • There are several types of interactions between species, referred to as: • competition • predator–prey relationships • parasitism • mutualism • commensalism.

17. Interactions in a living community • Interactions can involve members of the same or of different species. • Competition within and between species occurs when resources are limited: • Intraspecific competition: within a species • Interspecific competition: between more than one species. • Competition between populations in a community is reduced when there is niche separation.

18. Competition can be in the form of visible fighting and threats or in a non-visible form known as: • ALLELOPATHY – Chemical inhibition – the release of a chemical be a plant, which prevents the germination or growth of another plant species. • Pine trees are renowned for this. • Pheromones – are very important chemicals used for non-competitive communication between organisms, usually to attract a mate.

19. Predator-Prey Relationships • One species (predator) kills another (prey) • Carnivorous heterotrophs have: • Structural, physiological and behavioural features assisting them to obtain food. Eg. Spiders build webs, big cats have canine teeth, cooperative hunting by dolphins. • They have different strategies in obtaining their prey. Eg Coral polyps capture their prey, including fish, using the stinging cells on their ‘arms’ and a lion will stalk and then pounce, surprise and chase it’s prey and use teeth and claws to kill it.

20. Prey are not always caught • Due to structural, behavioural and biochemical features. • Structural: camouflage- look like something else to disguise and mimicry – look like something that is not appetising. • Behavioural: remaining still or playing dead, keeping lookout and hiding, schooling – safety in numbers. • Biochemical: some animals eat plants which makes them distasteful to others. These are often brightly coloured to warn predators eg. Monarch Butterfly.

21. Herbivore-Plant Relationships • Most herbivores are insects • Plants cannot run away or hide from herbivores so how do they defend themselves? • Horns, spines, stinging hairs; • Various plant species also produce allelochemicals  • Some of these chemicals include cyanide which can kill or deform insects

22. Ecosystems Collaborative Task • Download diagrams from the student portal. • Use Bubbl.us.com to create your own ecosystem mind map – to be done in pairs. • Use as many keywords as you can from the list below. Use the diagrams as a guide to include examples where possible. • Ecosystem • Community • Population • Habitat • Microhabitat • Niche • Autotrophs • Heterotrophs • Decomposers • Detritivores • Biotic and Abiotic Factors • Competition • Predator–prey • Herbivore-plant • In a PowerPoint slide, insert one diagram. • Using the text box function, label your diagram with as many of the keywords as possible (listed above).

23. Parasite-Host Relationships • In Animals: • an organism (the parasite) lives on or in another kind (the host) and feeds on it, typically without killing it, but: • the host suffers various negative effects in this relationship and only the parasite benefits. • Eg ticks and mammals • It’s estimated that parasites outnumber free-living species by about four to one. • EXOPARASITES – live ‘on/outside’ their host. • Eg. Fleas, ticks, leeches and fungi such as Tinea. • ENDOPARASITES – live ‘in’ their host. • Eg. Tapeworm and roundworm

24. Parasitoids •  Are a varied group of organisms, mainly small wasps and flies, that are like parasites. (The suffix -oid means ‘like’.) Parasitoids kill their hosts, which are usually another kind of insect. • They take some time to do this, unlike a predator-prey relationship in which the death of they prey is very quick.

25. Parasite-Host Relationships in Plants • Two kinds of parasite–host relationship can be recognised,: • Holoparasitism, in which the parasite is totally dependent on the host plant for all its nutrients. Eg. Rafflesia - forms largest flower on earth • Hemiparasitism, in which the parasite obtains some nutrients, such as water and minerals, from its host but makes some of its own food through photosynthesis. Eg. Mistletoe

26. Mutualism • Aprolonged association of two different species in which both partners gain some benefit. • Eg. Lichens consist of algae and fungi • Trapezia crab and coral polyps • Nitrogen fixing bacteria and certain plants which cannot extract Nitrogen form the air.

27. Commensalism •  (= ‘at the same table’) refers to the situation in which one member gains benefit and the other member neither suffers harm nor gains apparent benefit.  • Eg. Clown fish and Sea Anemones

28. Symbiosis • Interactions such as parasitism, mutualism and commensalism are sometimes grouped under the general term symbiosis (= ‘living together’) - close associations between two species that have evolved over geological time.

29. Summary of Symbiotic Relationships

30. Natural Succession • In an ecosystem, changes to physical and chemical features can cause a community to change. • Succession - The natural replacement over time of one community by another community with different dominant species. • Primary succession: ecological succession occurring in an area that was not previously colonised. Eg after a larval flow creates a new plateau. • Secondary succession: establishment over time of replacement communities in an area following an event that removes the original community. Eg a bushfire

31. Pioneer Species • The first species to become established in a ‘new’ habitat. • can survive under harsh conditions . • adapted for dispersal and rapid reproduction. • typically r-selected species.

32. Climax Community • Succession stops when a stable community becomes established, with no further change in the dominant species. • This stable community is known as the climax community. • The climax community depends on the physical features in the area (aspect, altitude, temperature, rainfall and soil type) Read example page 448