Chapter 45 Flashcards
Whats population thinking?*
The understanding that variations within a population can lead to differential survival and reproduction, leading to changes in the characteristics of the population over time.
Sea otters and population ecology
Sea otters are a top-down keystone species that let kelp forest proliferate through their consumption of sea urchins
3 types of population densities
random, clumped, uniform
Random distribution
Species are spread in a random way because they have no criteria for space (dandelions)
Uniform Distribution
The even spread out of species in an area (American Robin)
Clumped distribution
species are clumped together (elephants potecting young/weak from predators by clumping up)
How can distribution be tied to species?
The distribution of a species is closely related to its ecological niche, which determines the environmental conditions and resources that the species requires for survival and reproduction.
What are methods of sampling in nature
Sedentary and Motile
Sedentary sampling
Sedentary sampling is a type of sampling technique used in ecological research, where organisms that are immobile or move very little are sampled at a particular location (transects and quadrats).
transects
type of sedentary sampling technique that involve systematically sampling along a straight line or path to gather data on the distribution and abundance of organisms or other ecological features.
quadrants
Quadrants are a type of sedentary sampling technique that involve placing a frame of a known size over a specific area, and then counting or measuring the organisms or other ecological features that occur within the frame to estimate their abundance or density.
Motile sampling
Tagging and animal and recapturing them to sample how populations move/ hotspots of species
Sedentary vs Motile
Sedentary is better for immobile species while motile are better for mobile species
Age structure
ammount of living induviduals by age
Life table
A graph that measures probability of survival and reproduction
K-selected vs. r-selected species
K: slow growth, delayed reproduction, low fecundity, high parent care
r: rapid growth, early reproduction, high fecundity, and low investment in parental care
fecundity
ammount of offspring produced by a reproduction event
Survivorship curves
Type1: K-selected species, survivorship dips down near end of life expectancy
Type2: No correlation between age and when species die (linear)
Type3: R-selected species, survivorship dips down beginning of life expectancy
Population pyramids
measurement that researchers use to study human age structure
Life history
allocation of resource togrow, reproduce, and survive
Semelparity
Singular reproductive event (salmon)
Iteroparity
Multiple reproductive events (rabbits)
How fitness trade offs can influence population dynamics
Fitness trade-offs refer to the fact that investing resources in one aspect of an organism’s biology (e.g., growth, reproduction, or survival) may come at a cost to other aspects. These trade-offs can have important effects on population dynamics by affecting the balance between reproduction and survival, and the resulting growth rates and population sizes.
What events can increase exponential growth
Colonization of new habitat, Devestation/recovery
Carrying capacity
max ammount of organisms a habitat can support (if exceeded, mass death occurs)
Density dependant facotrs
Factors of surviorship that are influenced by density (disease)
Density independent factors
Factors of survivorship that are not influenced by density (weather patterns)
Types of desnity dependant factors
competition, disease, predation, toxic wastes, social behavior
Interspecific
Competition between multiple spp.
Intraspecific
competition in one spp./ cohort
Metapopulations
Populations that are fragmented whicih have pathways that connect eachother in some way
Why is metapopulations importnat for conversation
If metapopulations are sustained and habitat corridors are conserved, a extinct species in one area can be replrenished naturally
Habitat corridors
Connecting fragmented habitats for conservation
Christmas island example of habitat corridors
millions of crabs migrate to reproduce and the crabs have historically died because of cars. To avoid this issue, pathways/bridges were created to help these crabs reproduce.
**Problems with a growing human population&replacement rate
Replacement rate is the idea
Community vs populations
A community is all populations of interacting spp. living in an area while populations deal with the ammount of aone species in an area
Fitness
choices and events that affect energy avaibility towards growth/reproduction
.
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In each interaction between species what should you think about?
- Affect of distribution and abudance
- Agents of selection
- Outcomes are dynamic and conditional
Types of interactions and their fitness trade offs
Commensalism: +/0
Competiton: -/-
Consumption: +/-
Multualism: +/+
Does alturism exist in the natural world? explain
Altruism can exist in the natural world because it can provide indirect benefits to the altruistic individual, such as increased inclusive fitness or reciprocal benefits from other individuals in the group. Additionally, altruistic behaviors can be favored by natural selection if they enhance the survival and reproductive success of genetically related individuals, which can increase the frequency of altruistic genes in a population over time.
Why is competition not good for both species?
By definition, competition is -/-, but why? Well, there is an idea of competitive exclusion principle that states it is not possible for a spp. to coexist within the same niche. They are both expending energy and resources in the struggle for limited resources, such as food, water, or territory. As a result, both species experience reduced growth rates, reproduction, and survival compared to what they would experience in the absence of competition.
Competitive exclusion principle
not possible for 2 species to exists in the same niche, one spp will be better at the niche than another
Fundamental niche vs. Realized niche
Fundamental niche is all of the possible areas of resource a species can used
Fundamental niche vs. Realized niche
Fundamental niche is all of the possible areas of resource a species can used
Realized niche is the result of competition (since some part of their fundamental niche is outcompeted, it it not worth the energy to fight for it. Rather it would be better to go for a niche that has no competition)
Niche differentiation
The process of changing resources use (happens in realized niche)
Character displacement
Change of traits due to niche differentation
Example of niches in intertidal areas
Species in intertidal areas are sperate because of their niche preferences and they survive.
3 types of consumption
Herbivory: plants
Predation: animals
Parasitism: Small ammounts of host organisms
3 Tyoes of parasitism
Endoparasite: live inside host (tapeworm)
Ectoparasite: live outside host (tick)
Parasitoids: free living adults, but larvae are parasites (wasps)
Types of defenses
Constitutive: Defenses that are always present (tutrle shells)
Inducible defenses: Defenses that are in a response to predation (frogs with bad tasting skin, mussles grow thick shells near crabs)
Types of mimcry
Batesian: nontozix resemble dangerous (snakes with the red black yellow your a dead fellow, red yellow black you are okay jack)
Mullerian: Two harmful spp. resemble each other
Key attributes that affect community structures
- total # of spp.
- sum of interaction among spp
- relative abudance of spp
- abiotic and biotic factors
Food chain vs food web
Chains are linear while webs represent all consumption interactions in a community
Keystone species
Species that is integral to an ecosystem
Bottom up vs. Top down contorl
Bottom up control: a keystone species being the very bottom of a food web (kelp)
Top down control: a keystone species being at the very top of a food web (sea otters and wolves)
Trophic cascade***
What is a disturbance in a community
Any strong short-lived distribution that change ammount of living an non living organisms
Three factors to think about in a disturbance
- What happened? (Type)
- How often? (frequency)
- How bad? (severity)
Disturbance regime
predictable disturbances that happen in nature (sequoia trees needing fire to open pine cones to creat new trees)
Clemets v. Gleason
The debate between Clements and Gleason centered on whether ecological communities were highly integrated and stable entities, as Clements argued, or whether they were loose assemblages of species that responded independently to environmental conditions, as Gleason argued. Clements believed that communities were highly integrated and functioned like superorganisms, while Gleason believed that communities were simply collections of individual species that responded independently to environmental conditions.
Succession
Recorvery that follows a devastating event
Types of succession
Primary: removal of all organisms and fertile soil (lichens break down rocks to make soil feritle)
Secondary: removal of all organisms, but fertile soil
Pioneering spp. and types
First species to be alive in an succession event:
1. Facilitation: spp. makes favorible conditions (clovers help N fixation)
2. Tolerance: spp. makes no effect ono new spp.
3. Inhibition: Spp. inhibitis new spp. (black walnut tree has natural herbicide)
Shannons diversity index
A measure of species diversity in a community that takes into account both the number of species present and their relative abundances.
Pros: ability to capture both species richness and evenness, as well as its sensitivity to changes in both species richness and relative abundance
Cons: lack of sensitivity to the identity of the individual species present. assumes that all species are equally important. can be influenced by the presence of rare or common species
Richness vs evenness
Richness refers to the total number of different species while Evenness measures how evenly distributed individuals are
Island biogeography
A scientific theory that seeks to explain how species diversity and community structure vary among different islands.
- predicts that larger islands and those that are closer to the mainland will have higher species diversity
- important implications for conservation biology, as it helps to inform decisions about how to manage and protect isolated habitats.
Kinesis, taxis
Kinesis: random movement in response to stimuli
Taxis: planned movement in response to stimuli
Classical conditioning vs operant conditioning
Classical conditioning is when you learn to connect two things together
Operant conditioning is when you learn to change your behavior based on what happens afterwards
