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BIOL2010 L1-13
| Question | Answer |
|---|---|
| Define ecology | The abundance and distribution of organisms and the interactions that determine distribution and abundance |
| Exploitation competition and example | Indirect interactions between competitors for the same limiting resource eg. grasshoppers eating grass deprive others of food |
| Interference competition and example | Direct interactions between competitors for a shared resource eg. 2 vultures fighting over prey |
| Define predation | Consumption of one organism (prey) by another org (predator)when the prey is alive when it's first attacked by the predator |
| What are functional characteristics of grazers? | Grazers attack a large number of prey in their lifetime but don't usually kill their prey. They remove only part of each prey individual |
| Define direct defence against herbivory in plants and example | Plants defending themselves using their own defenses such as releasing toxins, having waxy cuticles |
| Define indirect defence against herbivory in plants and example | Features of a plant that indirectly protect it eg sending signal to attract natural enemies of herbivore, ant-plant association |
| Describe essential features of the life cycle of an iteroparous species and example | Breed repeatedly, devout some resources to breeding but the rest to survival and further breeding events eg humans |
| Describe essential features of the life cycle of a semelparous species and example | Single reprodcutive episode, no resources conserved for future survival, reproduction followed by death eg mayflies |
| What are inducible defenses and how do they protect plants from herbivore attacks? | Defences activated when attack occurs, don't need to spend unnecessary energy and lower fixed costs |
| Does predation always have a detrimental effect on prey populations? | It is harmful for individual being preyed upon but not always for the population - the individuals killed aren't necessarily a random sample of the popln and there may be compensatory growth, survival or reproduction in survivors |
| Explain why there is an underlying tendency for populations of predators and prey to cycle | When prey are numerous their predators increase in numbers, reducing the prey population which in turn cause predator populations to decline. The prey population eventually recovers, starting a new cycle |
| What is stratified random sampling and why is it useful? | Dividing a population into equal subgroups and taking random samples from each subgroup. Useful- avoids bias, improves representativeness of sample by reducing sample error |
| Explain the 'top-down', 'bottom-up' and 'side-by-side' views in ecological modelling | Everything is driven by predation therefore organisms at the top of the food chain are resource limited. Distribution and abundance of bottom-up determined by resource. Side-by-side is a competition view |
| How do conditions and resources differ? | Conditions - physiochemical features of environment(temp, pH) and can be altered by the organism but can't be consumed or used up. Resources are consumed by organisms in the course of their growth and reproduction and organisms may compete for resources |
| What is an ecological niche? | The niche of an organism is defined by its needs and tolerances |
| Define fundemental niche | A niche of a species in the absence of competition from other species. The organism is free from competition and can use a range of conditions and resources to its full potential |
| Define realized niche | A niche of a species in the presence of competition. The actual space an organism inhabits and resources it can access due to limiting pressures from other species |
| Define interspecific competition | Individuals of one species suffer a reduction in growth, survivorship and fecundity as a result of exploitation of resources and interference by individuals from another species |
| Define the Competitive Exclusion Principle | If 2 competing species co-exist in a stable environment, then they do so as a result of niche differentiation. If there's no differentiation, one of the competing species will eliminate or exclude the other |
| Define intraspecific competition | Interactions between individuals of the same species as a result of shared requirement for a resource leading to a reduction in survivorship, growth and reproduction of at least some of the competing individuals |
| What is it meant by one-sided competition? | Not all species suffer the effects of competition - a strong, early seedling will shade a stunted, later one |
| What is density dependence? | As density in a population increases, competition between individuals decreases the per capita birth rate and increases the death rate |
| How do net recruitment curves work? | net number of additions is small at lowest densities, increases as density rises, declines as the carrying capacity is approached and is then negative (deaths exceeds births) |
| How do sigmodial curves work? | When a population rises from a low density to carrying capacity. It increases in size slightly in the beginning then increases in size rapidly once the population grows. Then increases less until population reaches carrying capacity |
| What happens to consumers and consumption when food is unlimited? | Consumers eventually become satiated and consumption/benefit reaches a plateau. |
| What defines a true predator? Example | Invariably kill prey and do so more or less immediately after killing them. They kill several or many different prey individuals over their lifetime and often consume their prey entirely eg.lion |
| What defines a grazer? Example | Attack several or many prey items in their life, consume only part of each prey item and don't usually kill their prey instantly eg. cattle |
| What defines a parasite? Example | Only consumes part of each prey item (host), don't usually kill their prey especially in the short term)and attack one or few hosts in their life with which they form an intimate relationship eg.tapeworms |
| What similarities link parasitoids to true predators, grazers and parasites? | Intimately associated with host (like parasites), don't cause immediate death of host (like grazers and parasites) and their eventual lethality is inevitable (like true predators |
| What are the three types of functional responses of prey density effects on predator populations? | Type I- consumption rises linearly with prey density Type II- consumption rate rises with prey density but decelerates until a plateau is reached Type III- sigmoidial curve |
| What does a cohort life table show? | Records the survivorship of the members of a certain cohort over time |
| What does a static life table show? | Number of survivors of different ages in a population in a single period |
| What does an age-specific fecundity table show? | How many individuals of different ages contribute to births in the population |
| Explain the ant-plant relationship (Myrmecophytism) | The ant ant plant live in mutualistic association with one another. Plant provides ant with food and shelter while ant aids in pollination, seed dispersal and gathers essential nutrients |
| What are absolute methods in sampling populations? | Numbers per unit area of a habitat eg. mark-recapture |
| What are relative methods in sampling populations? | Numbers per unit effort eg traps |
| What is the difference between a static life table and a cohort life table? (I think this is an ok question... (gilly)) | Static life table - No. of survivors of different ages in a population in a single time period. Cohort lifetable - Monitoring what happens to individuals in a given cohort - born in a specified time period. |
| What is a unitary organism? | An organism that develops from a zygote through a set of irreversible changes eg humans |
| What is a modular organism? | Organisms where growth and differentiation occurs at meristems along roots and shoots eg. most plants, colonial animals |
| What does a lifetable show? | A age specific summary of the mortality rates operating on a population |
| What do fecundity schedules show? | Show how patterns of fecundity change with age per unit time |
Created by:
cmw001001
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