Unit/Sem 1 Biology Exam (Combine with other decks for Unit 1 Examination) Flashcards
What is Biodiversity?
Biodiversity refers to the great variety of life that exists in our biosphere on the ecosystem, species, and genetic level.
Species Diversity
The range of all the different species (organisms capable of interbreeding and producing fertile, viable offspring)
Genetic Diversity
Refers to the range of all the different genes in a species which code for different characteristics/traits (allelle forms)
Benefits of higher genetic diversity
Greater adaptability, Resistance against diseases
Ecosystem Diversity
The range of all different ecosystems (made up of interactions between biotic and abiotic components)
Biodiversity Hotspots
Are regions with numerous endemic species and a large number of endangered and threatened species
What are Spatial Scales?
Spatial Scales refers to the space being occupied.
What are Temporal Scales?
Temporal Scales refers to biodiversity in an area over a period of time
Two types of Ecosystems are…
Terrestrial and Aquatic Ecosystems
Phylum Chordata possess … …. …. at some stage in their development
Dorsal Notochord, Dorsal Nerve Cord, Pharyngeal slits
What are Biomes?
Biomes are regions of the earth with similar abiotic features
How are terrestrial ecosystems distributed?
Mainly the result of climatic variation.
4 ways to classify Aquatic environments
Aquatic environments include both marine (saltwater) and freshwater environments.
Still water or moving water
What is Climate defined as?
Climate is the atmospheric weather of an area, measured and average over a long period of time
What is Humus? What is rate of decomposition a limiting factor for?
Decomposition of plant and animal debris. The rate of decomposition is a limiting factor for forest growth
What is Substrate
Supporting surface on which an organism such as a plant grows.
What is Soil Type?
location, depth, texture, colour porosity, pH, water-carrying capacity and nutrient status.
Depth of photic zone, ecosystem type and implications for plants and animals
Photosynthesis occurs in photic zone (first 200 m of ocean depth)
90% marine life resides in photic zone
Classifying ecosystems using biotic factors example
Dominant Species, usually a plant, K-Selected or Keystone/Foundation e.g. Mangrove Swamp
An Amino Acid is?
A nitrogen containing compound, building block of proteins
Photosynthesis reaction
Carbon dioxide + Water -> Glucose +
Oxygen
Sunlight
Chlorphyll
What is a community?
A community is a group of organisms of different species that live in close enough proximity to interact with each other.
What is Competition defined as?
When individuals compete for a finite resource that limits their survival and reproduction.
What is Collaboration?
Is the working together of members of the same species that benefit all members
Predation
One organism the predator kills/eats part of another organism, the prey for its food.
Predator Prey Relationship Mutual Fluctuations
Overtime the predation relationship results in fluctuation of both population sizes.
Disease
The interaction between a disease-causing organism/agent and the host
Symbiosis Definition
Symbiosis is the general term for a relationship in which individuals of two or more species live together, benefitting at least one of the species.
Three types of symbiosis and outlines
parasitism: one species, the parasite, benefits at the expense of the other, the host
mutualism: both species in the relationship benefit and neither is harmed
commensalism: one species benefits and the other neither benefits nor is harmed.
What is parasitism?
Specific Example
Parasitism is an interactive relationship between two species: a parasite and a host. The parasite is an organism (such as a bacterium, virus, fungi, worm or arthropod) that lives on or in another organism, known as the host.
Dog (Host) and Heartworm (Parasite) Infection
What is Mutualism?
Specific Example
An interactive relationship where both organisms benefit. In the absence of these relationships, many species would become threatened or extinct because they cannot continue to survive by themselves.
Hummingbird and Flower (Pollination)
What is Commensalism?
Specific Example
Commensalism is a one-sided interaction between species. Only one of the two organisms involved, the commensal, benefits from the interaction; the other organism does not benefit, but it is not harmed.
Cattle Egret (Commensal) and Zebra (Unaffected) - Zebra kicks up beetles and bugs which cattle egret eats while riding zebra
Association
An interaction between two or more different species
Niches
Particular set of abiotic and biotic features present in an ecosystem which aids a particular species to survive.
Ecological Niche
The way in which a species functions in their environment.
E.g. when they eat, what they eat, where they live, when they reproduce, relationships with other organisms etc.
7 types of Relationships
Disease
Predation
Collaboration
Competition
Mutualism
Parasitism
Commensalism
Fundamental Niche (potential): Finches example
Ideal niche a species would occupy if there were no competitors, predators or parasites.
The fundamental niche of a finch may a whole tree.
Realised Niche (actual): Finches Example
Results from an organism’s inability to exploit the resources of its habitat because of restrictions.
The realized niche of a finch is from the middle downwards of a tree due to predation and competition (e.g. eagles)
Competitive Exclusion Principle?
Example
The competitive exclusion principle postulates that no two species can occupy the same exact niche in the same exact environment over an extended period of time
When the species grew as two separate cultures, with a constant source of food, the population numbers increased exponentially until they reached what is known as a carrying capacity of the culture. However, when the two species were grown in the same culture, P. aurelia had a competitive advantage over P. caudatum
What is habitat
Habitat is the area of an environment where an individual of a species lives, feeds and reproduces.
What is a population
A population is a group of organisms of the same species that live and interact together and with each other
Role of the Sun geochemically?
-Ultimate source of energy in food webs
- Warms atmosphere that drives all of the geochemical processes, tides, weather systems and ocean currents
How (organisms?) which cannot sunlight produce energy
Chemotrophic organisms such as Archae bacteria can break down small inorganic chemical compounds containing sulfur etc. for energy and matter
Biomass Definition
What Standard and Unit is it measured in?
The total amount of biological matter (living or dead) in a given area, at the time of measurement, that can be used as an energy source.
Dry weight (g m-2).
How do Autotrophs (producers) make food for themselves?
Synthesize organic compounds from inorganic raw materials.
Productivity
Percentage of energy entering an ecosystem which is incorporated into biomass
Heterotrophs
Rely on autotrophs directly or indirectly for their energy needs and matter needs.
Primary Productivity
Percentage of energy entering an ecosystem which is incorporated into biomass involving primary producers
What is Photosynthetic efficiency
Factors Affecting
How well a producer converts light energy into carbohydrates/sugars (glucose) during photosynthesis.
Depends on:
- Amount of light
- Temperature (rate of
chemical reactions)
- Availability of raw materials.
Gross Primary Productivity (GPP)
(SI) unit?
Total amount of energy that flows through the producers (kJ m-2 year -1).
Highly Efficient energy producer example?
Phytoplankton
Net primary productivity (NPP)
Formula?
SI units?
Net primary productivity (NPP) is the amount of energy available to consumers after cellular respiration.
It is calculated by
Net production = gross production – energy lost in respiration
mass: g m–2 year – 1
energy: kJ m – 2 year – 1
What is Cellular Respiration? Who performs it, consumers or/and producers?
Formula?
Extraction of energy stored in chemical bonds by cellular respiration (Consumers and producers)
Glucose + Oxygen -> Carbon dioxide + water + ATP (energy)
What is biogeochemical process?
The way in which chemicals (such as nitrogen and carbon) are transferred/transformed or stored between the living and abiotic features of an ecosystem
The Carbon Cycle
The carbon cycle is the biogeochemical cycle by which carbon is exchanged between the biosphere, geosphere, hydrosphere and atmosphere of Earth.
What are components that store more carbon that they release in the carbon cycle called? What processes moves carbon between these?
Reservoir (Long Term or Large) or Sink
Processes that move carbon between these include photosynthesis, burning of fossil fuels, and respiration
How do Living things release carbon dioxide into the atmosphere mainly?
Respiration
How is organic carbon that is locked in dead organisms returned to the carbon cycle? Which organisms is this done by?
Decomposition (Decomposers or Detritivores)
Describe the process of decomposition in relation to the carbon cycle
Detritivores and Decomposers return the remaining organic carbon inside of dead organisms is released back into the atmosphere as carbon dioxide, as both decomposers and detritivores undergo respiration.
What is the role of Detritivores? Example
They break down dead organic matter (Detritus) into smaller organic parts (e.g. worms)
What is the role of scavengers? Examples
They feed on carcasses of dead animals e.g vultures and hyaenas
What is the role of decomposers? Examples
Break down complex organic matter into simple inorganic matter (molecules) which is recycled as nutrients by plants. Common examples are Fungi and Bacteria
What happens to waste products in highly anaerobic conditions?
In these situations, decomposers may be unable to fully break down the matter, so it will accumulate over time and may form fossil fuels such as coal, and oils and gases derived from them
What are carbon sources?
Things or places where carbon is released into the atmosphere significantly more than is stored
How important is carbon to life? What organic matter or molecules is carbon, the building block of?
Most abundant element in life. Source of energy and builds up cells. Ammino Acids, Carbohydrates, lipids, nucleic acids and proteins
What biological molecules are mainly composed of nitrogen?
Proteins and ammino acids
Which 4 specialized bacteria’s metabolic activities does the nitrogen cycle depend on?
- Nitrogen-fixing bacteria
- Ammonifiers (decomposers)
- Nitrifying bacteria (nitrifiers)
- Denitrifying bacteria (denitrifiers)
What are Nitrogen-Fixing Bacteria and what is their role?
Symbiosis?
Nitrogen Fixing bacteria absorb atmospheric nitrogen (N2) from the air and trap it in soil and convert it into ammonium (NH4+). Nitrogen Fixation
- Some of these bacteria have a mutualistic symbiotic relationship with legume plants so that instead of being free-living in the soil, plants accommodate them as organs on their roots called nodules.
What is the role of Ammonifiers in the Nitrogen Cycle?
What type of plants is their process beneficial to?
Take organic wastes (animal excrement / dead bodies)
convert it into ammonia (NH3). Ammonification
Ammonia is only nutritionally useful to legume plants.
What is the role of nitrifying bacteria (nitrifiers) in the nitrogen cycle?
Convert Ammonia (NH3) into nitrites (NO2-)
then into nitrates (NO3-). This is called Nitrification.
What is the role of Denitrifying bacteria (denitrifiers) in the nitrogen cycle?
Converts Nitrates (NO3-) to atmospheric nitrogen (N2). Denitrification
Only non-organic process which fixes nitrogen?
Lightning
What is a Keystone Species and why is it so important?
- It is a species can exert a large effect on population numbers of other species in the community.
-The niche of a keystone species includes highly influential relationships with many species in a food web
An example of a nutrient Recyling keystone species? What they do?
Termites are detritivores (think about breaking down of wood and flow on recycling effect)
An example of a seed dispersal keystone species and what they do?
The Southern Cassowary. Eats parent plant’s seeds and excretes it far away and increases biodiversity, therefore termed “The rainforest gardener”
An example of a predation keystone species and what they do?
Purple Sea Star - Keeps mussel populations under control
What is Population Dynamics?
Important Factors?
The ecological interactions (biotic and abiotic interactions) that lead to fluctuations in population size.
It refers to how populations of a species change in size and structure over time. Rates of reproduction, death and migration are important factors in population dynamics
What is Carrying capacity?
The maximum population size of the species that the environment can sustain
Population Composition includes…
Includes the characteristics of a population, such as age, sex ratios, age structure (the number of organisms for each age group), fertility rate and average number of offspring per female.
Population Dynamics - Distribution Patterns, give examples for each
Clumped (Schools of Fish)
Uniform (Penguin colony)
Random (Cacti in desert)
Population Dynamics - What are Stable ecosystems
Relatively Dynamically Stable, holding K-selected species
Population Dynamics - What are Unstable Ecosystems
Mainly composed of r-selected species. Have major fluctuations in population sizes. Usually after some sort of natural disaster or calamity. Hosts r-selected opportunistic species.
What characteristics do K-Selected Species have? (Give Examples of species) Usually endemic or invasive? Population Growth?
Usually, they are Endemic. They have longer life spans, take longer to reach maturity, and relatively larger size. More parental care. Examples are oaks, elephants, tortoise, kangaroo. Population growth is usually steady and can approach carrying capacity
What characteristics do r-selected species have (Give examples of species) Usually endemic or invasive? Population Growth?
May be invasive. r-selected species have shorter life spans, mature faster, and have high breeding capability. Less paternal care. Examples are cane toads, rabbit, weeds etc. Opportunistic species. Peak quickly and crash due to inability for environment to carry such a large number, shorter life spans etc.
Growth Rate definition? Unit?
Growth Rate refers to the number of individuals being added or subtracted per hundred or per thousand presents in the population per unit of time (usually per year).
Open ecosystem?
An open ecosystem is open to migration and/or immigration after environmental changes
Closed ecosystem?
Does not permit migration or immigration to occur. Population sizes normally influenced by births and death
Population Growth Rate Formula
Pop growth rate = (birth rate + immigration rate) - (death rate + emigration rate)
Density Definition, Distribution Definition, Total Abundance Definition, Population Fertility definition
Density: number of organisms per unit area
Distribution: Locations and presence of individuals with an area
Total Abundance: Total number of organisms
Population Fertility: Reproductive capacity of females in a population
What does a population pyramid show?
The number of organisms, male and female, in age groups (Age Structure)
Why does carrying capacity exist? Factors?
Because an ecosystem only has a limiting number of resources
Population Limiting Factors:
- Availability of resources such as food, water, air, light etc.
- Predation
- Competition
What is Biotic Potential?
The intrinsic rate of increase (r) is the rate at which a population would grow if it had unlimited resources.
(No population can increase its size indefinitely.)
Population Growth Chart
Check Notion and Answer
Examples of Density-Dependent Factors and Definition? Survival?
Disease, Predation, Competition, Parasitism
Are factors whose severity depends on the density of the overall population which it affects. All individuals of the population do not have the same chance of survival.
Examples of Density Independent Factors and Definition? Survival?
Environmental Conditions, Natural Disasters
Factors that affect all individuals in a population regardless of how dense the population is. All individuals have an equal chance of survival.
Population Size Formula?
(Total area/Area Sampled) x number of individuals counted
Population Density Formula?
Number of individuals counted/area sampled
Describe Capture-Mark-Recapture
Animals are caught randomly without being hurt - They are marked in a way that does not reduce their chance of survival and allowed to mix with unmarked individuals of the population - Random recapture takes place and number of marked organisms and total number of organisms captured are counted
Assumptions when capture-mark-recapture
1.There is no birth, death, emigration or immigration (closed population)
2. Identical Sampling methods at all times
3. Marking tag does not affect the survival rate of the animals
4. All members recaptured and captured have an equal chance of being captured
Total Population (N) formula
(N) = {No. marked in first sample (M) x total number of animals recaptured (n)}/ number of marked individuals that are recaptured (m)
When is a line graph used?
Used for continuous data
When there is a direct trend, line of best fit is appropriate, otherwise points must be connected together.
When are column Graphs used?
Qualitative data with limited possibilities
When is a Histogram used?
Categorized discrete data
What is validity?
Has the hypothesis been tested fairly
What is reliability?
Has there been repetition or replication?
What is accuracy?
Has the dependent variable been measured fairly?
What is a systematic error?
One that can be fixed by changing the method
What are mistakes
Due to carelessness or bias
Random Errors
Unpredictable or Uncontrollable errors - Increase sample size to fix
Animals’ ethics, Three considerations
Reduction: Fewer number of animals needed
Refinement: Enhance wellbeing
Replacement: Avoid animals or use an animal with lower sentient value
Ecological Succession? What is a Climax Community?
Succession is a process of change in community composition and structure, usually towards the establishment of a stable ecosystem. It includes changes in both the biotic and abiotic factors in an ecosystem over time. When a stable community is established, it is known as a climax community.
What is Nudation?
Nudation is when a natural disaster etc. leaves an area with bare rock and no organisms or soil
Four main stages of Primary Succession with explanations? Time? Biodiversity?
- Pioneer plants colonies (lichens, liverworts). They secrete organic acids which attack the rocky surface in the process of weathering, allowing windblown dust particles to settle in cracks.
- Pioneer Plants die living a shallow layer of soil on and in the rock. This leads to moss growth. When the moss dies, nutrients are available to the soil. Over time bacteria, fungi and invertebrates form a small community. Roots weather the rocks more.
- Early colonising plants are r-selected species. Typically have effective seed dispersal, rapid growth and rapid reproduction. Numbers usually die out when more competitive species move in.
4) New community forms: establishment of autotrophs, small herbivores, immigrant species from surrounding areas. K-selected species
Takes hundreds/thousands of years. Increases local biodiversity.
What is Secondary succession? Steps-Time? Biodiversity impact?
Process of change in an ecosystem when a previously established community is taken over by a new group of organisms. E.g. after flood, fire, human intervention (logging, land clearing).
Soil is already present
The process starts at STEP 2: Soil formation. It continues with steps 3 then 4 of primary succession.
Biodiversity increases. Faster process (50-100 years).
Climax Community Biotic Features Succession?
K-Selected Trees, Outcompete other species. e.g. Jarrah Forrest
What are the three factors that Fire Depends on?
Fuel, Ignition, Oxygen
Fire intensity mainly depends on?
Weather and fuel load
Rate of fire spread is mainly affected by…
Windspeed, Fuel Moisture, Fuel Load etc.
2 Benefits of Fire
Returns nutrients to the soil that were previously locked up in plant biomass
The heat of the fire can lead to biotic changes, because some species of bottlebrushes, hakeas, some acacias and eucalypts regenerate from fire-released seeds
The heat of the fire can lead to biotic changes, because some species of bottlebrushes, hakeas, some acacias and eucalypts regenerate from fire-released seeds
2 Benefits of Smoke
Leads to germination of some plant species
Adaptation to fire - Lignotuber
Swelling at the trunk of
a tree that stores energy that can regenerate the tree If the top is damaged by fire.
Adaptation to fire - Epicormic buds
These buds are protected by thick bark, which can withstand the intensity of heat from fires. If a fire burns the top/crown of the tree it will stimulate the buds to spout.
What are Fire Regimes and what determines them?
Fire regimes are a sequence of fires that results in long term change in an ecosystem.
They are determined by:
- the season in which fires occur
- the intensity of the fires
- how frequently the fires occur.
Negative Human Impacts on Ecosystems
Urbanisation- habitat destruction & fragmentation
- Agriculture
- Land and soil degradation
- Salinity
Habitat destruction
the total degradation of a habitat, due a human activity that greatly impacts the ecosystem.
Fragmentation
the separation of some parts of the habitat of an ecosystem into isolated sections resulting in isolated groups of organisms that were once part of a larger population.
What is Urbanisation?
Urbanisation is the extreme modification of an ecosystem by humans to support a human population of gradually increasing density.
What is Agriculture?
Agriculture is the practice of farming, cultivating soil, growing crops, raising animals.
Factors affecting Land and Soil Degradation
Overgrazing
Hard hooves farm animals
Shallow rooted plants
Reduced tree cover
Overuse of fertilizers
What is Wind erosion?
Wind erosion is the removal of topsoil by wind
Dryland salinity - What is salination?
Salination is the increase of salt concentration in agricultural soil which makes it infertile.
What is the main cause of dryland salinity?
Removal of deep-rooted perennial trees for agriculture
What are the steps of dryland salinity
- Human Population increases, leading to more consumption needs
- Farming increases, with removal of deep-rooted vegetation
- Deep rooted plants no longer access underground aquifers and use it in transpiration. Shallow rooted plants cannot access the water table
- Watertable rises, as it rises, salt from surrounding soil dissolves into the water
- Water evaporates at the soil surface, leaving behind salt in the topsoil, leading to infertility of soil
What are introduced species?
Introduced species are species that humans have intentionally or unintentionally moved from their native location to a new ecological region.
What are invasive species?
In their new location, introduced species are are without their natural limiting factors usually limiting their growth (relationships). They are introduced species that establish populations in new areas; out-competing natives, changing the composition and structure of the ecosystem
What is Overharvesting?
Means harvesting a species at a rate that exceeds the replenishing rate of the population. The sum of new individuals from births and immigration does not exceed the total individuals lost to death plus emigration.Unsustainable
What is Eutrophication?
Eutrophication is a process that occurs when excess nutrients, particularly nitrogen and phosphorus, enter a body of water and become highly concentrated, leading to algal bloom
Steps leading to Eutrophication
- Farmers dealing with nutrient-deficient soils use fertilizers.
- Excess nitrogen and phosphorous not absorbed by roots are often leached from the soil by run-off (rainwater or irrigation).
- The run-off can reach local water bodies such as lakes and cause algal blooms
- Blocks sunlight from entering. When this happens, autotrophs that live under the surface die.
- Algae die and are decomposed by bacteria.
- As bacteria consume the dead algae, they use large amounts of oxygen from the water, which depletes oxygen levels. The water can become hypoxic (low in oxygen) and possibly anoxic (completely devoid of oxygen).
- This kills populations of other aquatic organisms such as different species of fish
- Positive Feedback Loop
What is Biomagnification?
Biomagnification is the sequence of processes in an ecosystem by which higher concentrations of a particular non-biodegradable chemical are reached in the tissues of organisms higher up the trophic levels of a food chain. Chemicals accumulate in the next trophic level, leading to increased concentrations of chemicals.
What is DDT?
DDT insecticide.
It entered the food chains as the pesticide was sprayed on insects that were then eaten by insectivores, in turn eaten by carnivores etc.
In humans: higher incidences of cancer, infertility, miscarriage and diabetes.
Birds: population decline, thinner eggshells.
Evidence of Global Warming - Ice cores
Collect ice cores containing bubbles which can be used to analyse past carbon dioxide levels and temperature data. This shows the positive relationship between carbon dioxide levels in the atmosphere and temperature data
What are greenhouse gases? Examples?
Gases that trap heat in our atmosphere. Methane, Water Vapor, Carbon Dioxide
What is the natural greenhouse effect?
Effect of greenhouse gases in the atmosphere, which prevent some of the heat from escaping Earth’s atmosphere. Keeps Earth warm and drives global temperature.
What causes the enhanced greenhouse gas effect
Human activities such as the burning of fossil fuels, and deforestation have led to a negative increase of greenhouse gas concentration in the atmosphere. This retains too much heat.
Corals Symbiosis Description
Corals have a mutualistic relationship with algae (Zooxanthellae)
The coral provides zooxanthellae with a protected environment and compounds/reactants for photosynthesis (Carbon Dioxide, Nitrate, Phosphate).
The zooxanthellae produce oxygen and supply coral with the products of photosynthesis (Glucose), they also remove coral wastes.
Bleaching Threshold temperature and time. What happens to zooxanthellae
The Bleaching Threshold is 29.3 degrees. If the temperature stays above this for more than 4 weeks bleaching can occur. This is when the zooxanthellae leave the coral.
What are the three types of conservation strategies?
Environment, genetic, management (rescue, rehabilitation and treatment)
Which non-target species does bottom trawling affect?
Deep Sea Corals and Sponges
Do Human Activities decrease or increase biodiversity
Decrease
What is Trophic Efficiency? What percent usually? What percent is lost and to what is it lost, in what forms of energy?
The percentage of energy passed on to the next trophic level. Usually, 10%. 90% is lost to surroundings as heat energy and chemical energy as wastes.
Steps to drawing a pyramid of energy
- The bottom level should always represent a producer.
- Subsequent levels should be labelled primary consumer, secondary consumer and tertiary consumer.
- Each trophic level should be drawn to scale. Unless you have alternative data, measure one-tenth the length of the preceding trophic level (this represents the average energy transfer efficiency of 10%).
- Use labelled arrows to indicate energy leaving each trophic level in the form of heat.
