How is population ecology different from community ecology?
Community Ecology is how groups of organisms interact with their environment and each other
... [Show More] in a given geographic area. Population Ecology would just look at 1 species
What is an example of how an interaction can affect the evolution of both interacting species?
Species interactions such as parasitism, herbivory, predation, commensalism, mutualism can affect evolution
What interactions are classified as enemy-victim interactions? How are enemy-victim interactions described and defined?
Parasitism, predation, and herbivory are enemy-victim. They have a +/- interaction where there is a consumer and consumed
How do scientists characterize and describe the vast diversity of parasites?
Ecto- outside of
Endo- inside of
Micro- small
Macro- big
Describe how hosts and parasites, insects and angiosperms, and predators and prey co-evolve.
There is a strong selective pressure on the host of all of those interactions as they would try to evolve to better deal with the parasite/predator
How do scientists determine if an interaction is truly parasitic> How does this relate to studies of sea birds?
To be truly parasitic, the parasite must increase its fitness and the host must decrease its fitness as a result of the interactions. Parasites are often very overlooked but their biomass is extremely large
What causes the negative effect of herbivory on a plant, beyond the loss of tissue that is consumed?
Herbivory influences the plant population size and growth rate because the plant has to invest energy into dealing with herbivory and not just to grow. It can also influence plant evolution with plant defenses
Can you put Kingdom Animalia, Subphylum Hexapoda, Domain Eukarya, and Phylum Arthropoda in order from the broadest grouping to the most narrow designation?
Eukarya, Animalia, Arthropoda, Hexapoda
What traits are exhibited by all insects?
Exoskeleton of chitin, jointed appendages, 3 body segments (head, thorax, abdomen), 6 legs, ecdysis
What are some reasons insects are important in communities?
Insects are dominant herbivores and can be pollinators
What advantage do monarch butterflies gain from feeding on milkweed as caterpillars?
By feeding on milkweed (although it takes significant energy to break down the toxin in milkweed), the monarchs steal the defense
How do predators affect B, I, D, and E of their prey populations? Be sure to connect your answer to the "ecology of fear"
B: might decrease if the prey lower their feeding rates and stay where it is safer even if the food isn't as good
I: prey might immigrate into lower predation areas even if the food isn't as good
D: death increases from predation
E: prey might leave to avoid predation
*energy is taken up by avoiding predation which could be used elsewhere
*stress hormones can affect birth rate
Can predators maintain prey populations at the prey's carrying capacity?
No- predation is not a regulating factor. Prey's population size would be lower than carrying capacity
What types of defenses have evolved in prey and/or plant populations to help them avoid predation or herbivory?
Size, camouflage, poisons, spines/armor, speed, or tolerance (giving up to conserve energy)
Why are some defenses constitutive, and some are inducible? Shouldn't there just be one best defensive strategy?
Constitutive defenses require a lot of energy to maintain, so sometimes inducible defenses are better (they are more energy efficient). And there can't be one strategy because the more defense at the lowest cost the better, but it also depends on the situation
What are some differences between parasitism, herbivory, and predation?
Parasites are smaller and do not immediately kill their hosts, while predators are larger and kill for food. Herbivory is with plants
What is an ecological niche?What is niche overlap? In nature, do the niches of two species tend to exactly overlap?
A niche is all the resources used and the conditions tolerated for a species. Niche overlap is when 2 species share resources, habitats, etc. We typically see partial overlap, but not complete overlap
When/where does the greatest competition between two species occur?
The greatest competition occurs within the niche overlap when species are competing for resources
How is competition defined? For what do different species compete?
Competition is a -/- interaction where both species experience and reduction in fitness through fighting over a resource. It can be intraspecific or interspecific. Competition can be asymmetric (where one species loses more) or symmetric (both species lose equally)
Does competition always involve direct contact or fighting?
No, it can be subtle like tree roots fighting for space and resources
What is competitive exclusion? When does it occur?
Two species with identical niches cannot coexist. There will always be a stronger competitor in this situation, and they will competitively exclude the weaker species. Competitive exclusion occurs when niches overlap AND competition is asymmetric
What happens when niches do not completely overlap?
When niches only partially overlap, weaker competitors will use non-overlapping resources
How can you tell what the effect of an interaction is on a species?
When fitness is changed, the interaction had an effect on the species (this can take the form of change in growth rate, change in size, etc.)
What is the fundamental niche of a species? What is the realized niche of a species?
The fundamental niche of a species is all the resources and conditions tolerated in the absence of interspecific competition. The realized niche of a species is all the resources and conditions tolerated in the presence of interspecific competition
Which is usually bigger: the fundamental niche or the realized niche? What is the exception to that general rule?
Realized niche is usually smaller than the fundamental. The exception is with mutualism where the realized grows in the presence of the other species
What are mutualistic interactions? What is the impact of the interaction on fitness of both partners? What are four key points about mutualisms?
Mutualisms are +/+ interactions where both species benefit (experience an increase in fitness) due to the others' presence. Mutualistic interactions always involve cost on both sides, but the benefit of the interaction is greater than the cost. This interaction is not altruistic (it only acts in self interest). It can also change to parasitism when one species cheats.
What are Rhizobium bacteria? Where do they live? What do they provide to their host? What do they gain in return?
Rhizobium bacteria build nodules in the roots of legumes and help them fix nitrogen gas into ammonia (NH4).
What are mycorrhizal fungi? Where do they live? What do they provide to their host? What do they gain in return? How common are they?
Mycorrhizal fungi live in association with plant roots. They help plants scavenge for phosphorus around roots. In return the plants supply carbohydrates. More than 90% of land plants have interactions with mycorrhizal fungi.
Who fixes nitrogen in the ocean?
Other bacteria and archaea can fix nitrogen (Trichodesmium)
What has been the impact of mutualisms on land plants? What are angiosperms?
Plant-pollinator interactions were critical to the evolution of land plants. Angiosperms are flowering plants that evolved to have a mutualistic relationship with pollinators
How do angiosperms reproduce? What is pollination? What is fertilization?What structure contains the baby plant?
Angiosperms reproduce by being pollinated. Pollination is the movement of pollen (of either the same flower or a different flower) from the (male) anther to the (female) stigma. Fertilization is the connection of 2 haploid cells (when pollen meets the eggs). The ovule contains the "baby plant"
What does "haploid" mean? What does "diploid" mean? What is mitosis?
Haploid is n, diploid is 2n. Mitosis is cell division where cells can grow and reproduce
What is coevolution? What is notable about the Madagascar comet orchid?
Coevolution is the reciprocal evolutionary influence between 2 interacting species. Each species exerts a selective pressure on the other so they evolve together. (Plants only want 1 pollinator so that they get the correct pollen, so they have highly specific coevolution)
What does it mean to say a mutualist is "cheating"?
When partner in a mutualistic relationship starts to cheat, they gain from the partner, but the other partner loses. Can switch over time with evolution or with population changes
Within Domain Eukarya, which groups have been influenced by endosymbiosis?
All groups. All eukaryotes have mitochondria, and plants have chloroplasts
What kinds of organisms are photosynthetic but are not plants?
Some bacteria use sunlight as a source of energy
What type of organism has the most similar sequence of DNA as the DNA found in the mitochondrion? What type of organism has the most similar sequence of DNA as the DNA found in the chloroplast?
Mitochondrion are similar to alpha-proteobacteria. Chloroplasts are similar to cyanobacteria
Which came first, the mitochondrion or the chloroplast? How do you know?
The mitochondria came first. We know because all life with a mitochondria traces back to 1 common ancestor.
What key pieces of evidence support the endosymbiosis theory?
1- Mitochondria and chloroplasts are similar in size and shape to free-living bacteria
2- Mitochondria and chloroplasts divide by binary fission and have circular DNA
3- Mitochondria and chloroplasts have double membranes
4- Similar DNA to alpha-proteobacteria and cyanobacteria
What cellular functions are carried out by mitochondria and chloroplasts?
Mitochondria produce ATP through cellular respiration and chloroplasts facilitate photosynthesis to produce glucose
What does the direction of an arrow in a food web mean? Which direction should food web arrows point, and what do those arrows represent?
The direction of an arrow represents where energy is flowing TO.
What do the prefixes photo- and chemo- mean? What do the prefixes auto- and hetero- mean?
Photo- uses sunlight
Chemo- uses chemical (organic or inorganic) compounds
Auto- Uses CO2
Hetero- Uses organic carbon
What groups of organisms are often missing from food web drawings?
Decomposers
Why aren't wolves classified as ecosystem engineers, using the Bio 171 definition, but beavers are?
Beavers actually change the "type" of environment that species will live in. They more directly and more significantly impact it.
How do trophic omnivores differ from primary, secondary, and tertiary consumers?
Trophic omnivores consume multiple trophic levels
What are direct and indirect effects, and how do you distinguish between direct and indirect effects?
A direct effect is one species on another whereas an indirect effect is one species on another mediated by a third species
How is a trophic cascade different from a change at the primary producer or primary consumer level? How does a trophic cascade diagram differ from a food web?
A trophic cascade starts at a higher level (a top predator) and effects alternately positively and negatively down the pyramid. A trophic pyramid doesn't show direct effects of interactions.
In a trophic pyramid (pyramid of energy), where is the amount of energy the highest? How does the amount of energy change from the base to the top of a food web? By how much? What limits the number of trophic levels in an ecosystem?
The energy is the highest at the lowest level of the pyramid (primary producers). Energy reduces with each move up the pyramid (by ~10%). Trophic efficiency limits the number of trophic levels in an ecosystem
How do we measure and calculate trophic efficiency? Describe real-life examples of CE, AE, and PE. How does cellular respiration relate to trophic efficiency?
Trophic efficiency is the product of Consumption Efficiency, Assimilation Efficiency, and Production Efficiency
Why is > 80% of land used for livestock, but that corresponds to just 18% of calories in food?
Livestock is higher in the trophic pyramid, so they have maintained less energy
How do keystone species differ from dominant species? What are some examples of both dominant and keystone species?
Keystone species have a disproportionately effect compared to their biomass. Dominant species have a lower impact per individual (because their biomass is so large). Pisaster ochraceous is a keystone species, and mussels are a dominant species
What are some ways that parasites can influence food webs?
Parasites can hurt a keystone species or a dominant species which can cause a trophic cascade
What some reasons why we should care about energy flow and primary production? What are some cases where we want to promote primary production? What are some cases where there is too much primary production?
Primary production determines how many levels of a trophic pyramid can exist. When we want more/fewer species above the primary producers, we can manipulate the amount of primary production
What are the four components of an ecosystem that are linked by energy flow? Where does the energy that flows through a food web usually come from? Which organisms "capture" that energy when it enters a food web?
Primary producers, consumers, decomposers, abiotic environment. Energy starts from the sun. Primary producers capture this energy and put it into the system
What happens to the energy in a top predator when it dies? Do primary producers use that energy?
Decomposers will turn the biomass of the predator into nutrients for the primary producer and the rest will escape as heat
What organisms can carry out photosynthesis? Can all autotrophs carry out photosynthesis?
Phototrophs can carry out photosynthesis. Not all autotrophs can use the sun as energy (chemoautotrophs in the deep sea vents don't even have access to sunlight).
Where does the energy for photosynthesis come from? What are the inputs to the photosynthesis reaction? What are the products of it? What is the energy from the sun converted into? Who uses that energy?
The energy for photosynthesis comes from the sun. Photosynthesis:
Sun + H2O + CO2 --> CH2O + O2
Primary consumers use this energy
Which of the following domains has/have photosynthetic organisms: Archaea, Bacteria, Eukarya? Are land plants the main photosynthetic organisms in the world, when considering the amount of photosynthesis that occurs? Consider the number of taxa across the tree of life that are photosynthetic: are land plants the main photosynthetic organisms in the world?
Bacteria and eukarya. More than 45% of the planet's photosynthesis is carried out by microscopic photoautotrophs.
What is a key characteristic of land plants? What does "alternation of generations" mean?
All land plants have alteration of generations meaning all plants have some part of their life where they are haploid cells and then later turn into diploid cells
What is a key characteristic of vascular plants? What does this trait allow them to do?
Vascular plants have xylem and phloem which store and transport water and nutrients
What trait is shared by gymnosperms & angiosperms? What trait is characteristic of angiosperms?
Gymnosperms and angiosperms both have seeds and pollen, but angiosperms have flowers and fruit
What does the term "phytoplankton" mean? Which of the following domains has/have organisms that are considered phytoplankton: Archaea, Bacteria, Eukarya?
Phytoplankton are microscopic photoautotrophs that do most of the planet's photosynthesis. They belong to bacteria and eukarya [Show Less]