Chapter 3 Flashcards
Natural Selection
- Process that makes changes possible in living things
- Members of a species having certain characteristics that give them an advantage over other members of that species will be in better condition to mate
- These individuals then may pass these favourable characteristics on to their offsprings
Adaptive Radiation
- The change from a common ancestor into a number of different species that radiate out to inhabit different niches
- Each species is adapted to a particular niche and therefore gathers different types of food
Ecological Succession
- Changes that take place over time in the types of organisms that live in an area
- Primary and Secondary
Primary Succession
- Occurs in an area where no soil exists
Pioneer Species
- Lichens and other organisms that are the first ones to survive and reproduce in an area
- Change the biotic and abiotic environment in a variety of ways (create soil)
Climax community/Mature community
- Forms from ecological succession
- May appear unchanged but experience constant changes
- Multiple and sustainable trophic level and
Secondary Succession
- Occurs as a result of a disturbance to an area that already has soil and was once the home of organisms
- Occurs much faster
What causes primary succession?
- Retreating glaciers
- Cooler lava from volcanic eruption
How do lichens create soil?
- First carried by wind and rain
- Obtain nutrients from rock by secreting chemicals that break down the rock
- After they decay, they also added organic matter to the developing soil
Flooding
- Occurs in coastal areas when the volume of water exceeds the ability of the water body to contain it
- Can result in soil erosion and soil pollution and widespread disease
Tsunamis
- Caused by large earthquakes or underwater volcanic eruptions
- Can change the composition of the soil
- Plants that cannot survive in a salty environment die
Drought
- Below-average rainfall in an area over a period of time
- Can destroy habitats when water becomes scarce and plants and animals die
- Can result in crop failures and livestock deaths
Insect Infestations
- Younger trees defend against insects by producing resin
- Events that keep beetle infestations in check (long, cold winters) are no long occurring
Resin
- Produced by trees to trap and flush the adult beetles out of the tree
When is resin flow reduced?
- Many insects attack at once
- The tree is stressed from overcrowding, drought or grazing by animals
Sustainability
- Ability of an ecosystem to sustain ecological processes
- Using the resources of an ecosystem to meet our needs without reducing the function and health of the ecosystem
Land Use
- Ways we obtain and use natural materials
Habitat Loss
- Destruction of habitats, which usually results from human activities
Habitat fragmentation
- Division of habitats into smaller isolated fragments
- These isolated pockets of ecosystems affect plant pollination, seed dispersal, wildlife movement and plant, animal reproduction
Deforestation
- Practice in which forests are logged or cleared for human use and never replanted
Soil Degradation
- Can occur when water and wind erosion removes topsoil from bare land
Soil Compaction
- Occurs when soil particles are squeezed together and the air spaces between the particles are reduced
- Caused by vehicles and grazing animals
- Reduces movement of water, air and soil organisms
- Growth of plants is hindered nad run-offs increased
Aeration
- Mechanically removes small plugs of soil
- One method that reduces run-off by improving the movement of air and water through soil
Resource exploitation
- Exploiting natural resources
Contamination
- Introduction of chemicals, toxins, wastes, or micro-organisms into the environment extinction concentrations that are harmful to living things
Overexploitation
- Use or extraction of a resource until it is depleted
- Cause extinction
Extinction
- Dying out of a species
Traditional Ecological Knowledge
- First Nation’s understanding of the plants, animals and nature
- Reflects human experience with nature gained over centuries
- Takes the form of stories, songs, cultural beliefs, rituals, community laws and practices in agriculture, forest, ocean
Polyculture
- Growing a variety of plants
- Increases amount of nutrients and helpful micro-organism
- Reduces soil erosion and weed invasion
Native Species
- Plants and animals that naturally inhabit an area
Introduced/Foreign Species
- Carried into the area intentionally or accidentally
- Most were harmless and beneficial
- Some are invasive species
Invasive Species
- Organisms that can take over the habitat of native species or invade their bodies
What are the four major impacts of invasive species?
- Competition
- Predation
- Disease and Parasites
- Habitat alteration
Invasive Species Competition
- They disturb the balance established by the original community (of sharing resources)
- Outcompete native species for essential resources such as food and habitat
Ex) Carpet burweed
Invasive Species Predation
- More impact on prey as they may not have adaptations to escape/fight the invasive species yet
- Ecosystem is affected if keystone species are preyed upon
Ex) Yellow crazy ants prey on red crabs
Invasive Species Disease and Parasite
- Weaken immune response of native species
- The weakening provides more opportunities for less dominant species to outcompete other species, severely altering the ecosystem
Ex) Parasite sea lamprey in Great Lakes
Ex) Blister rust (Fungi) attacking Whiteback pine
Invasive Species Habitat Alteration
- May change light levels, decrease dissolved oxygen in ocean, change soil chemistry, increase soil erosion
- Makes the ecosystem unsuitable for native species
- Upset balance of nutrient cycling, pollination and energy flow
Ex) White boars (spreading weeds)
What are some introduced invasive species in BC?
- Eurasian milfoil
- Norway rat
- American bullfrog
- European starling