Download Ecosystems Unit Summary

Science 10
Final Review
Ecosystems Unit Summary
Chapter 1
1. Factors that Influence the Characteristics of Biomes
• Biomes have similar abiotic and biotic components.
• Abiotic factors influence the characteristics and distributions of biomes.
• Biomes are often named for their dominant vegetation or for a geographical or physical
characteristic.
• Temperature and precipitation are affected by latitude, elevation, and ocean currents.
• Climatographs summarize the climate or average pattern of weather observed over a period of
years.
2. The Distribution of Biomes
• Biomes at the same latitude tend to have similar characteristics.
• Tropical rainforests occur between the Tropic of Capricorn and the Tropic of Cancer.
• Boreal forests are found above the Tropic of Cancer, tundra is found north of the boreal forest,
grassland is often in the middle of continents, and temperate rainforest is mainly on coasts.
• Several different biomes can be observed as the elevation of a mountain increases.
3. Adaptations and Biomes
• Adaptations are characteristics that enable organisms to better survive and reproduce.
• Structural adaptations are physical features of an organism’s body that contribute to the survival of
the organism, such as a thick white coat in winter.
• Physiological adaptations are physical or chemical events within the body of an organism that
enable survival, such as warm-bloodedness.
• Behavioural adaptations are what an organism does to survive in the unique conditions of its
environment.
4. Abiotic Interactions in Ecosystems
• Abiotic components in ecosystems include oxygen, water, nutrients, light, and soil.
• Oxygen is needed to burn energy and is found in many types of organic molecules.
• Water and light are needed for photosynthesis.
• Water transports nutrients.
• Nutrients are needed for plant and animal growth.
• Soil provides nutrients and supports many species of small organisms that help recycle nutrients
and rid of pollutants.
5. Biotic Interactions in Ecosystems
• Biotic interactions in ecosystems include trophic and symbiotic relationships as well as competition
and predation.
• Commensalism is a symbiotic relationship in which one species benefits and the other species is
not helped or harmed.
• Mutualism is a symbiotic relationship in which both organisms benefit.
• Parasitism is a symbiotic relationship in which one species benefits and another is harmed.
• Niches describe the roles and relationships of an organism in the environment.
• Competition is a harmful interaction between species when they compete for the same resource.
• Predation describes interactions where one organism benefits and the other is harmed.
• Both predators and prey have adaptations for this relationship.
• The amount of biodiversity is often an indicator of the health of an ecosystem.
Chapter 2
1. Energy Flow in Ecosystems
• Plants are called producers because they make carbohydrates during photosynthesis.
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Final Review
• Carbohydrates are eaten by primary consumers or herbivores. Animals that eat other animals are
secondary or tertiary consumers and are called carnivores.
• Energy flows from producers to primary consumers and then to secondary consumers and is
modelled in food chains and food webs.
• Decomposers recycle nutrients, which can be reused by plants to make nutrients that will provide
energy to the ecosystem again.
• Food pyramids model how energy is lost at each trophic level.
• About 90 percent of the energy taken in is used for chemical reactions and will be lost as heat to
the ecosystem.
• Only 10 percent of the energy is available for the next trophic level.
2. Nutrient Cycles in Ecosystems
• The nutrients carbon, nitrogen, and phosphorus move in and out of the abiotic and biotic
components of terrestrial and aquatic ecosystems.
• Nutrient cycles are nearly in balance without human interference.
• Carbon and nitrogen cycle between living organisms and the atmosphere.
• Phosphorus enters the environment from sedimentary rock.
3. Human Activities and Ecosystems
• Land clearing, agriculture, urban expansion, mining, industry, and motorized transportation add
additional nutrients to the nutrient cycles.
• Changes in nutrient cycles affect biodiversity.
4. Effects of Bioaccumulation
• Synthetic chemicals enter the environment in air, water, and soil.
• Plants take up these chemicals. Animals eat these plants, and the chemicals bioaccumulate in
animal tissue.
• Persistent organic pollutants such as DDT remain in the ecosystem for many years after their
introduction.
• Contaminants, such as persistent organic pollutants and heavy metals, can bioaccumulate and
biomagnify, affecting consumers and the health of ecosystems.
• Chemical accumulation is measured in parts per million (ppm).
• Lead, cadmium, and mercury are the three most polluting heavy metals.
• Heavy metals and persistent organic pollutants affect the health and reproductive ability of
organisms.
• If a keystone species is affected by bioaccumulation, the ecosystem will be strongly affected.
• In bioremediation, living organisms are used to clean up chemicals in the environment.
Chapter 3
1. How Changes Occur Naturally in Ecosystems
• An individual with a favourable characteristic that gives it an advantage over another will survive
and reproduce. This is natural selection.
• When two or more species arise from one species, this is adaptive radiation.
• Adaptive radiation and natural selection are processes that change organisms in response to
changes in the abiotic and biotic components of an ecosystem.
• Ecological succession changes the abiotic components and biotic components of the ecosystem
over time.
• Primary succession occurs in an area where no soil exists. After a series of abiotic and biotic
changes, the area will develop into a mature community, such as a boreal forest.
• Pioneer species, such as mosses and lichens, are organisms that take hold during primary
succession.
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Final Review
• Secondary succession occurs after a natural event and may take only decades because soil,
nutrients, and some life already exist.
2. How Natural Events Affect Ecosystems
• Flooding results in erosion and soil pollution and can cause widespread disease.
• Tsunamis destroy plant and animal habitats, and the soil is left salty from the ocean water.
• Drought can destroy habitats and decrease plant productivity, causing animals to die.
• Insect infestations destroy older weaker trees and so are beneficial to the forest, but large
infestations can cause the loss of habitat for many animals and the forest canopy is reduced,
causing changes in plant life.
3. How Humans Influence Ecosystems
• Resource use refers to the ways we obtain and use materials from the biosphere.
• Human expansion into ecosystems has caused the loss and fragmentation of habitats.
• Deforestation to clear land for agriculture causes loss of species and soil degradation.
• Agricultural practices cause soil run-off, which could add excess nutrients to the environment. In
addition, agricultural practices could add pesticides to the environment.
• Resource exploitation in mining can contaminate water and soil with toxic chemicals.
• Overexploitation affects food web interactions.
• Resource management practices can be improved with information gained from traditional
ecological knowledge.
4. How Introduced Species Affect Ecosystems
• Invasive introduced species can affect native species through competition, predation, disease,
parasitism, and habitat destruction.
• Introduced invasive species compete against native species for essential resources, such as food
and habitat.
• Prey often does not have adaptations to escape or fight invasive predators.
• Parasites, bacteria, and viruses can weaken the immune system of native species.
• Some invasive species change the habitat, making it unsuitable for native species.