Chapter 9 Habitats, environment and survival

1. Chapter 9 Habitats, environment and survival Page 256 - 296

2. O2 CO2 Nutrients Ecology • Ecology is the study of the relationships between organisms and their physical (abiotic) and living (biotic) environment: • Relationships involve interactions with the physical world as well as interrelationships with other species and individuals of the same species.

3. Habitat • An organism’s habitat is the physical place or environment in which it lives. • Organisms show a preference for a particular habitat type, but some are more specific in their requirements than others. Lichens are found on rocks, trees, and bare ground. Most frogs, like this leopard frog, live in or near fresh water, but a few can survive in arid habitats.

4. Habitat Type: Habitats can be described as being either: • Terrestrial (for example, deserts, grasslands, rainforests etc), or • Aquatic: • Freshwater: lakes, rivers, ponds • Marine: coral reefs, coastal sea floor, seas, oceans etc • Estuarine: river mouths • Example: Within a woodland habitat, woodlice may be found in the microhabitat provided beneath the bark of the rotting wood. Microhabitat: Defn: the more localised part of a general habitat where an organism lives (examine Figure 9.7. Describe: a) The habitat; b) Microhabitats

6. Abiotic Factors that influence a habitat • The physical conditions influence the habitat in which an organism lives. These include: • substrate • humidity • sunlight • temperature • salinity • pH (acidity) • exposure • altitude • depth • Each abiotic (or physical) factor may be well suited to the organism or it may present it with problems to overcome.

7. Biotic Factors that influence a habitat • The living factors that influence the habitat in which an organism lives include: • predators • prey • competition • disease • Each biotic (or livingl) factor may be well suited to the organism or it may present it with problems to overcome.

8. Resources in a Habitat • The habitat provides organisms with the following resources: • Food and water sources • Mating sites • Nesting sites • Predator avoidance • Shelter from climatic extremes • However, the organism may or may not have the adaptations to exploit all the available resources fully.

9. Range of Habitats • Range: The geographical area that encloses all the habitats where a species lives denotes the range or distribution map of that species. • Over time the range of a species may increase or decrease. • Many native species have a shrinking range. • In contrast, many introduced species have increased their range. Examine Figure 9.9 – 9.11 Discussion: What factors affect the range of an organisms Habitat?

10. Resources in a Habitat • The habitat provides organisms with the following resources: • Food and water sources • Mating sites • Nesting sites • Predator avoidance • Shelter from climatic extremes • However, the organism may or may not have the adaptations to exploit all the available resources fully.

11. Dingo Habitats • Dingoes are a highly adaptable species found throughout Australia in ecosystems as diverse as the tropical rainforests of the north and the arid deserts in the central Australia. • Within each of these ecosystems, they may occupy a range habitats, each one offering slightly different resources.

12. Biozone: Dingo Habitats page 245

13. Hills Floodplains and Hills Floodplain Floodplains Hills and Floodplain

14. Dingoes prefer riverina habitat.This is inferred by the fact that they spend a disproportionate amount of time in riverina compared to the other habitats available. Stoney areas avoided Dingos are caught and fitted with radiotransmitters. At set intervals the from the individual animals can be recorded and mapped giving a picture of movements over time 4194 4 years Provides more accurate information about size and boundaries of range Possibly plays some part since the areas with very low kangaroo abundance also have low dingo numbers. However other limiting (i.e available of suitable riverina habitat) are importnatHigh kangaroo numbers does not necessarily equate with high dingo numbers. Trade off between food and other factors Home range is larger where water (and vegation) are scarce. Areas with poor water supply offer little little in the way of vegatation diversity

15. Quick Check Questions

16. Technology as a tool • Using technology is an important tool in the study of habitats, particularly those over large areas. • Remote Sensing (such as Landsat) carries sensors that detect the distinctive ‘signatures’ of different kinds of vegetation. • Tracking or telemetry techniques are restricted to animals of restricted size to allow a tracking device to be fitted to them. • Tags attached to animals can record data on animals’ interactions with their environment.

17. Quick Check Questions

18. Mudfish Habitat Preference • The New Zealand black mudfish is a wetland species of uncertain conservation status. • Its habitat preference has been described in relation to meanwater depth, turbidity, and degree of habitat disturbance. Black mudfish Neochanna diversus

19. Tolerance range Optimum range Number of organisms Unavailable niche Marginal niche Preferred niche Marginal niche Unavailable niche Law of Tolerance see page 243 Biozone • The law of tolerance states that “For each abiotic factor, an organism has a range of tolerances within which it can survive.” Examples of abiotic factors that influence size of the realized niche:

20. Community and Niche Defn: Community • Members of the different species that share one habitat form the living community of that habitat. Case study pg 268 Defn: Niche • The niche of a species identifies its way of life or role in a community. • A niche can be identified in terms of the degree of use of resources. • Activity Manual pg 247 • Quick Check Questions: 5 – 11

21. Habitat Adaptations Activity patterns Presence of other organisms Physical conditions Ecological Niche text page 269 • The ecological niche describes the functional position of an organism in its environment. • A niche comprises: • the habitat in which the organism lives. • the organism’s activity pattern: the periods of time during which it is active. • the resources it obtainsfrom the habitat.

22. The Fundamental Niche • The fundamental niche of an organism is described by the full range of environmental conditions (biological and physical) under which the organism can exist. • The realized niche of the organism is the niche that is actually occupied. It is narrower than the fundamental niche. • This contraction of the realized niche is a result of pressure from, and interactions with, other organisms.

23. Gause’s Principle • Gause’s competitive exclusion principle states:“two or more resource-limited species, having identical patterns of resource use, cannot coexist in a stable environment:one species will be better adapted and will out-compete or otherwise eliminate the other(s)”. • If two species compete for some of the same resources (e.g. food items of a particular size), their resource use curves will overlap. In the zone of overlap, interspecific competition is the most intense. Zone of overlap Amount eaten Species A Species B Resource use as measured by food item size

24. Competition • Competition describes the active demand between two or more organisms for a resource. • Competition may be: • Intraspecific: between individuals of the same species. • Interspecific: between individuals of different species. • Each competitor is inhibited in some way by the interaction. Intraspecific competition: hyaenas Interspecific competition on a reef

25. Biozone: Ecological Niche page 244 Quick Check 8 – 11: page 270 • Mud at lake edge; probing with beaks; worms and small crustaceans • Deepest water; diving; small organisms at the botton etc In general, two or more different species cannot occupy the same niche in the same community for an extended period yes No yes

26. Quick Check questions 12 – 17 • Activity Manual page 231- 234

27. false true true P hygrometer Conductivity meter anemometer • Moisture • Temperature range • etc

28. false true false true

37. Surviving in the Australian Environment • Much of the Australian environment is distinguished by high summer temperatures, low and erratic rainfalls and mineral poor soils. • Adaptations for survival in the conditions prevailing in a particular environment may be structural, physiological or behavioural features. • Different vegetation type can be defined by light penetration, climate, dominant family. • The distribution of various vegetation types is influenced by environmental factors mainly related to climate, but also soil type.

38. Plant Adaptations to Australian Environments • Adaptations plants have for arid environments include:- - maximise water uptake – root systems- minimise water loss – leaf structure (SA: V)- produce drought-resistant seeds • Response to fire

39. Adaptations by Animals • Reproductive strategies • Sweeting/ panting • Behaviour • Torpor • Quick Check Questions 18, pg 282 • Activity Manual pg 239-40 and 241-2