Chapter 4 And C Flashcards
What is a species?
a group of organisms that can interbreed to produce fertile offspring
What is a sub-species?
a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics, but that can successfully interbreed
What is the difference between a detritivore and a saprotroph?
Detritivores obtain nutrients from detritus (decaying organic material and faecal matter) by internal digestion
Saprotrophs obtain nutrients from dead organisms by external digestion
How do you calculate population density?
Quadrant sampling:
- placed repeatedly in a sample area to provide reliable estimates
- placed randomly for population density
- presence/absence or % coverage can be recorded
- limitation; doesn’t work for larger organisms, (mostly just plants and small, slow moving animals)
How is energy lost from an ecosystem?
Energy can be lost as heat, and can also be lost through bones, hair, faecal matter, as organism don’t consume their entire prey. Also cellular respiration.
What limits the length of food chains?
Energy flow. Each trophic level receives less and less energy as the chain proceeds.
What does a pyramid of energy show? What units are used to represent the energy transferred? (know what it means not just the symbols used).
Shows the relative amounts of energy flowing through each trophic level. kJ m-2 year-1 (energy per unit area per unit time)
What is a carbon flux? Measured in?
Carbon flux = exchange of carbon between the atmosphere, the oceans and the biosphere. Measured in gigatons of carbon per year (Gt Cyr-1)
What is a methanogen?
An Archaean microorganism that produces methane as a metabolic byproduct in anoxic conditions
Outline the process of peat formation.
- Organic matter is digested by saprotrophs
- Saprotrophs assimilate some carbon for growth and release as carbon dioxide
- Organic matter is only partially decomposed
- Large quantities of organic matter build up
- Organic matter is compressed to form peat
What are greenhouse gases?
gases in the atmosphere that can absorb and reflect long wave radiation back to earth, keeping earth much warmer than it otherwise would be.
Where does carbon dioxide, water, methane, and nitrogen oxides come from?
Carbon Dioxide; cellular respiration, burning fossil fuels, exhausts from cars
Water; evaporation from oceans and transpiration from plants
Methane; methanogenic archaea preforming anaerobic respiration, melting of tundra
Nitrogen oxides and tropospheric ozone; combustion in the presence of nitrogen
What has caused an increase in greenhouse gases?
Human activity such as burning fossil fuels.
What is the impact of increased greenhouse gases in the atmosphere?
- Higher global average temperatures
- Frequent and intense heat waves
- Droughts
- Flooding
- Tropical storms
- Changes to ocean currents = colder temperatures
What is the impact of increased CO2 levels in marine environments, in particular coral reefs?
Coral bleaching. Increased carbon dioxide leads to ocean acidification which kills coral polyps, meaning reefs aren’t built anymore.
What is a niche?
The unique role a species plays in the community
What is the difference between a fundamental and a realized niche?
Fundamental:
- The potential mode of existence of the species given its adaptations
Realised niche:
- The actual mode of existence, which results from its adaptations and competition with other species
How does competition impact the niche of an organism?
If two species share a niche, this leads to inter specific competition for resources
- One species has the advantage
- Less well-adapted struggles to survive
- Will eventually be eliminated
What is competitive exclusion?
”no two species can occupy the same niche for extended periods of time”
What are the different types of relationships between species?
- Herbivory: primary consumers feed only on plant materials
- Predation: a consumer kills and eats another consumer
- Symbiosis: close and persistent interaction between two species (one or both can benefit)
- Mutualism: mutually beneficial symbiotic relationship, both organisms benefit from the relationship
- Commensalism: where one organism benefits and the other is unharmed
- Parasitism: symbiotic relationship. Parasite depends on host for food, host may be killed
Describe how the relationship between Zooxanthellae and coral is mutualistic.
Zooxanthellae lives in the tissue of the coral and gives it its colour. The coral provides a protected environment and compounds needed for photosynthesis. Zooxanthellae provides oxygen, help with removing waste, and supplies coral with nutrients.
What is biomagnification? Discuss an example (in detail, not dates etc but scientific detail).
Bio magnification is the process in which chemical substances become more concentrated at each trophic level. For example, DDT, this chemical can be washed into waterways and travel up the food chain starting with a zooplankton, small fish, large fish, and then fish-eating birds.
What are micro plastics? What is their effect on organisms? Discuss specific examples.
Micro: plastic debris that is less than 5mm (exfoliants, abrasives).
- Organisms such as lugworms consume sand and digest the microorganisms found on the surface of sand particles.
- Seeing as micro plastics as incredibly small, they can mix in with the sand that is eaten by the lugworms.
- The lugworms then become vulnerable to pathogens.
- Cause them to have less energy for churning up the bottom sediments
- One of their most important functions in the ocean ecosystem.
What are macroplastics? What is their effect on organisms? Discuss specific examples.
Macro: large, visible plastic debris larger than 5mm (bottles, nets, bags)
- Albatrosses skim the surface of the ocean to catch fish.
- They can pick up floating plastics in the water
- They feed this mix of plastics and fish to their chick
- Adults can regurgitate the plastic they’ve swallowed
- The chicks can’t so their stomachs become full
- The chicks may feel full – and not want to eat actual food
- They end up starving due to lack of nutrients
What is the richness and evenness?
Richness: the number of different species present
Evenness: if a habitat has similar abundance for each species present, the habitat is said to have evenness
How the Simpson’s reciprocal index be used to assess the biodiversity of an ecosystem? How do you interpret the values?
- Takes into account richness and evenness
- Lowest possible defined value of D is 1
- The higher the D value, the more bio diverse
What is in situ conservation? Ex situ conservation?
In situ: preservation of plant and animal species within their natural habitat
Ex situ: preservation of plant and animal species outside their natural habitats
What is a population growth curve?
Shows the numbers of a population over time
3 phases:
- Exponential: number of individuals increase at a faster rate (high natality, low mortality/ high immigration, low emigration)
- Transitional: growth rate slows down, population still increasing (increasing mortality, increasing emigration)
- Plateau: numbers of individuals have stabilised, no more growth.
(Natality = mortality, emigration = immigration)
How can the rates of natality, mortality, immigration and emigration be used to explain the shape of the sigmoid growth curve.
- Natality: the number of new individuals after successful reproduction/number of births
- Mortality: the number of deaths
- Immigration: the number of individuals arriving from other places
- Emigration: the number of individuals leaving a population
What is the role of bacteria in the nitrogen cycle? Give specific examples for the 3 bacteria species discussed.
Bacteria helps recycle the nitrogen through the environment
- Rhizobium: nitrogen fixing bacteria lives in root nodules. Convert nitrogen gas to ammonia
- Nitrobacter : lives in well oxygenated soils. Converts nitrites into nitrates
- Nitrosomonas: converts ammonia into nitrites (unusable to plants)
Describe the flow of energy through a food web
- food web shows how food chains are linked together into more complex feeding relationships
- food webs are more detailed/accurate;
- organisms can occupy more than 1 trophic level
- organisms can have more than one food source
- organisms can have more than one predator
What methods can be used to estimate population numbers of marine species?
- capture-mark-release-recapture: this sampling involves collecting a sample of animals, marking them, and then releasing them. Later collect another sample and from the number of marked ones recaptured an estimate of the pop can be calculated
- the Lincoln index can be used to estimate the pop using recapture data
How does effective management work to conserve species within national parks?
- in situ conservation
- biological control (living organisms or virus), chemical control (toxins), physical control (removal)
- designation of protected areas of land
- ecological monitoring of species
- interventions may be require to prevent competition from an invasive species
What does a niche include?
- where the organism lives (spatial habitat)
- what and how it eats (feeding activities)
- interactions with other species
