CHAPTER 9: HABITATS, ORGANISMS & SURVIVAL Unit 2: Area of Study 1 Today we will cover: Habitats Range Absence from a region Migration Niches

Habitat: where an organism lives  It is its location where an organism lives at a given time (therefore, it can change)  It is a location where an organism can fulfil its needs for energy & matter, and has appropriate conditions for survival & reproduction  ‘extreme environments’ refer to spaces that humans consider ‘unliveable’, still, organisms will make these their habitat if they are well adapted to the conditions.

 Habitats can vary widely in size- some organisms may occupy an ocean, a rainforest or a desert plain, others may occupy a small section on the underside of a rock.  Some terms used to describe habitats include terrestrial (land based) or aquatic (water based)  Microhabitat refers to the specific part within a habitat that an organism occupies. Ie, if the habitat is the ‘address’ the microhabitat is the ‘bedroom’ of the organism

Range: the distribution of habitats  The range of an organism refers to the geographic area where the species lives.  A large range does not necessarily mean large numbers of the species. It simply means they are spread over a greater distance.  Eg. The range of year 11 Bio2b students is currently this classroom (small) at lunchtime, the range will be the entire school grounds- does not mean that there are more of you!  See diagrams pg 261  Ranges can change dramatically over time due to changes in conditions, eg the introduction of a new species, hunting etc.

Moving between habitats  Some species move between habitats in a cyclical (often yearly) pattern  These organisms are called migratory  Why migrate?  Access to food may be limited in some seasons  Breeding may take place under different environmental conditions  To avoid ‘unfavourable’ weather conditions (wouldn’t we all like to do this!)

Migratory organisms  GO TO PAGE 262  Choose an example of a species of this kind and write 2 dot point explaining the species & its migration  GO TO PAGE 262  Choose an example of a species of this kind and write 2 dot point explaining the species & its migration Annual migration (example 1)‘Once in a lifetime’ migration

Absence from a region  When an organism is absent from a region there are several reasons why this may occur:  Unsuitable environment Weather conditions, soil composition, temperature range, wind conditions, humidity- may be inappropriate  Geographical barriers Barriers such as water masses, mountains, other significant disruptions to the environment such as major highways can cause the absence of a species that may be able to survive under the conditions  Competition Competition by another species for food or shelter can cause a species to be absent

Definition of niche  A niche refers to ‘where it lives and feeds, what it eats, when it feeds and environmental conditions it tolerates.  It tells us something about the way the organism lives and how it ‘fits into’ the overall habitat

 Biozone pg 274, 243, 244  Quick check pg 282, 291,  Chapter review 2, 3, 5, 6