Option C: Ecology & conservation C1: Species & communities

Vocab. review Ecosystem Species Population Community Habitat

Limiting factors Defined as: a factor that is most scarce in relation to an organisms needs. These can be any biotic or abiotic factors within an environment that affect the distribution of organisms. Plant distribution Animal distribution Abiotic variables Temperature Water availability Light intensity Soil pH Soil salinity Availability of soil nutrients Each organism has a tolerance range for each of these things. Water Breeding sites Food supply Territory Some organisms exhibit specific adaptations to an environment. Food availability, mating rituals, territory requirements and more are limiting factors (abiotic, biotic, behavioural etc.)

Epidalea calamita (Nutterjack toad) Example of a species requiring a very specific breeding site. Nutterjacks only lay their eggs on areas of sparse vegetation with a very slight slope on banks next to water in Northern Europe.

Sea ice phytoplankton Developed specific adaptations to survive very cold temperatures without freezing. These organisms are not adapted to survive in warmer waters, they have a specific temperature range.

Loxodonta africana (African bush elephant) This organism displays multiple adaptations to its environment: Large ears to reduce temperature Large feet Trunk

Transects A transect is another sampling method (similar to the quadrat). There are 3 main types of transect: 1. Line transect (record all the organisms that touch the line) 2. Belt transect (record organisms between two lines separated by a fixed distance) 3. Point transect (usually used with bird populations, researcher will stand in one randomly selected place and make observations)

A niche In an ecosystem each species plays a unique role. This is known as its ecological niche. Each species must have its own niche – nutrition requirements, abiotic requirements (temp. etc.) this includes the other organisms it needs to interact with. Two species with identical niches cannot survive in the same habitat indefinitely. This is known as the competitive exclusion principle.

The Bay-breasted warbler & the Yellow-rumped warbler Both birds are migratory and have very similar niches, but when they are both present in the same habitat their feeding behaviours change so they do not overlap. See graph 

Intraspecific interactions This is a way of classifying interactions between species in a community. There are several examples of common interaction. These are: Competition Herbivory Predation Parasitism Mutualism Commensalism In groups, pick one interaction. You are going to research this category of interaction and present your findings to the class next period. You should include: Definition, three examples. One should be easy to remember, one can be local the last one should be ‘interesting’!

Keystone species A keystone species is one which has a disproportionate effect on the structure of an ecological community. Californian Sea Otters are a good example. Otters feed on sea urchins and other invertebrates that graze on giant kelp. Without Otters, the grazers can destroy the kelp forest and as such a wide variety of organisms that depend on the kelp forest habitat for survival will be adversely affected. Kelp forests also absorb CO2 from the atmosphere. Find another (or more) examples.

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