chapter 9 habitats, environment and survival
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Chapter 9 Habitats, environment and survival. Page 256 - 296. O 2. CO 2. Nutrients. Ecology. Ecology is the study of the relationships between organisms and their physical ( abiotic ) and living ( biotic ) environment: - PowerPoint PPT PresentationTRANSCRIPT
Chapter 9 Habitats, environment and
survivalPage 256 - 296
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.
O2
Nutrients
CO2
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.
Habitat
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.
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
Microhabitat:
Defn: the more localised part of a general habitat where an organism lives
(examine Figure 9.7. Describe: a) The habitat; b) Microhabitats
Example: Within a woodland
habitat, woodlice may be found in
the microhabitat provided
beneath the bark of the rotting
wood.
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.
Abiotic 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.
Biotic Factors that influence 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.
Resources in a Habitat
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 – 9.11Discussion: What factors affect the range of an organisms 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.
Resources in a Habitat
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.
Dingo Habitats
Biozone: Dingo Habitats page 245
HillsFloodplains and HillsFloodplain
Floodplains
Hills and Floodplain
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
41944 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
Quick Check Questions
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.
Quick Check Questions
Mudfish Habitat PreferenceThe New Zealand black mudfish is a wetland species of uncertain conservation status.
Its habitat preference has been described in relation to mean water depth, turbidity, and degree of habitat disturbance.
Black mudfish Neochanna diversus
The law of tolerance states that “For each abiotic factor, an organism has a range of tolerances within which it can survive.”
Law of Tolerance see page 243 Biozone
Examples of abiotic factors that influence size of the realized niche:
Tolerance range
Optimum range
Unavailabl
e niche
Marginal
niche
Num
ber
of o
rgan
ism
s
Preferre
d nicheMarginal
niche
Unavailable
niche
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
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.
Ecological Niche text page 269
Adaptations
Physical
conditions
Activity
patterns
Presence of
other organisms
Habitat
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.
The Fundamental Niche
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.
Gause’s Principle
Zone of overlap
Species B
Resource use as measured by food item size
Am
ou
nt
eate
n
Species A
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.
Competition
Interspecific competition on a reef
Intraspecific competition: hyaenas
Biozone: Ecological Niche page 244
Quick Check 8 – 11: page 270
In general, two or more different species cannot occupy the same niche in the same community for an extended period
• Mud at lake edge; probing with beaks; worms and small crustaceans• Deepest water; diving; small organisms at the botton etc
yes
yes
No
• Quick Check questions 12 – 17
• Activity Manual page 231- 234
false
true
true
P
hygrometer
Conductivity meter
anemometer
• Moisture• Temperature range• etc
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.
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
Adaptations by Animals
• Reproductive strategies• Sweeting/ panting• Behaviour• Torpor
• Quick Check Questions 18, pg 282
• Activity Manual pg 239-40 and 241-2