T2W4 - Chapter 9 Ecosystems - Unit 9.1 Components PDF

Chapter 9 - Ecosystems Unit 9.1 - Components of an ecosystem In this Unit of work The following will be covered: ○ Ecology and the environment ○ Ecosystems ○ Abiotic and biotic factors ○ Environmental changes and its impact on populations Ecology and the environment...

Chapter 9 - Ecosystems Unit 9.1 - Components of an ecosystem In this Unit of work The following will be covered: ○ Ecology and the environment ○ Ecosystems ○ Abiotic and biotic factors ○ Environmental changes and its impact on populations Ecology and the environment Environment refers to the factors that affect an organism’s chances of survival over its lifetime. This includes abiotic (non-living) and biotic (living) factors. Ecology is the study of the interactions of the populations and environment within an ecosystem.  Delving further into the concept of ecosystems An ecosystem is a place where the organism and their physical surrounding form an environment different from other environments nearby. Ecosystems can also be looked at as the “organisms that live in that area” plus “environment” (defined in previous slide). Looking at “environments” Environments effectively equal to abiotic plus biotic factors: 1) Abiotic factors: Non-living factors, physical factors such as air quality and humidity, amount of sunlight, rainfall, wind, tides, waves, etc. 2) Biotic factors: Living factors such as predators, parasites, fungi, infectious bacteria and viruses, competitors and breeding partners. Question no.1 Define community, environment and ecosystem. (3 marks) Abiotic factors - water Water: Essential for all living organisms. Solvent for all materials in cells and allows numerous chemical reactions to occur. If there isn’t enough water, these chemical reactions won’t occur, cells die, leading to organisms death. Desert hopping mouse: Spends the day in the burrow (when it’s hot) and only leaves at night to feed allowing to conserve (save) Abiotic factors - temperature Temperature affects the speed that chemical reactions occur. As temperature increases, the reaction rate usually increases too. Temperature must be maintained within a narrow range for optimal functioning for the animal to survive. Animals are categorised as endotherms or ectotherms. Endotherms VS Ectotherms Endotherms are animals that have the ability to generate heat internally and control heat loss to keep their body temperature constant. Examples include humans, mammals. Ectotherms are animals that cannot maintain their own temperature. That is, they rely on the environment to heat themselves up. Examples include reptiles, crocodiles, lizards. Question no.2 Compare endotherms and ectotherms. (2 marks) Abiotic factors - fire Fires can begin naturally (thunder/lightning storms) or because of human activity. Aboriginal people have used fire for thousands of years to control the growth of plants and trees to improve growth of plants. They knew that many Australian plants regrow quickly after fires. Bushfires are necessary for some plants to germinate, grow and sprout. Examples: eucalyptus Biotic factors - what are they? Living things affect each other’s survival, Biotic factors more specifically refer to the interactions between living organisms, A lot of organisms depend on each other for survival - this is called interdependence. All organisms in an ecosystem are interconnected, affecting each other’s survival (helpful and harmful ways). Biotic factors - competition When organisms try to obtain the same resource, which may only exist in limited quantities, it is called competition. Competition occurs between species and between members of the same species. Chicks belonging to same coop will compete for chick feed for example. Biotic factors - predation When one organism kills and eats another, it is called predation. The organism doing the eating is called the predator. The organism being eaten is called the prey. Many examples, look on the right. Biotic factors - mutualism When a relationship between two organisms exists where both organisms benefit, it is called mutualism. The cleaner shrimp eats parasites on the skin of the fish. The cleaner shrimp and fish both benefit - the shrimp get good, the fish is cleaned and protected from parasites.  Biotic factors - parasitism When one organism benefits and the other is harmed, it is called parasitism. The parasite cannot survive without the organism it lives in. An organism called a parasitic wasp lays its eggs in insects such as caterpillars. The eggs feed off the caterpillar gaining benefit while the caterpillar is slowly killed. Biotic factors - commensalism When one organism benefits and the other is not harmed or benefited, it is called commensalism. A good example is barnacle growth on whales. Barnacles are a type of arthropod that grow on whales. The feed off the microorganisms out of the water while the whale is unaffected. Question no.3 Construct a table to summarise the biotic factors covered. (5 marks) Environmental changes Environments can and do change over time. Depending on the rate, manner and time of change, organisms that live in the environment may be affected in different ways. Birth and death rate - tied strongly with food availability. If food increases, birth rate increase. If food decreases, vice versa.