Integrated Biology Exam 1

True Features of Symbiotic Interactions

* Interactions where one species steals resources from another
* 2 organisms/species benefit from a close association and will die without it

Symbiosis

A close, long-term interaction btwn. 2 different species (living in close physical association)

Fitness

An organisms’ ability to survive and reproduce in a particular environment

Direct Fitness

The expected # of viable offspring an individual produces

Parasitism

An organism lives in or on another organism (its host) and benefits by deriving nutrients at the host’s expense

Ectoparasite

Lives on the surface of an individual

Endoparasite

Lives inside the organism

Social Parasite

One social organism parasitizing another social organism

Ecological Virulence

The host’s parisite-induced loss of fitness

Commensalism

A benefit to one and no “measurable” harm/benefit to the other associate

Mutualism

2 organisms of different species in a relationship in which each individual benefits from the activity of the other

Hypothesis

A prediction about the relationship btwn. variables

* implies proposed explanation for an observable event
* made on the basis of established facts
* the introduction to further investigation

Scientific Inquiry

* Consistency
* Observability
* Natural
* Predictability
* Testability
* Tentativeness

Consistency

Experimental procedures, obsv., and results are the same

Observability

The event (or evidence for event) can be observed with human senses (or extensions of them)

Natural

Accurate predictions and conclusions are based on natural causes (mechanisms). must be plausible

Predictability

the natural causes (mechanisms) can be used to make predictions

Testability

Controlled experiments can be designed to test the natural cause (mechanism) of the event

Tentativeness

Explanations (laws, theories, hypotheses) of the cause for the event are subject to revision and correction

Basic Research (Pure/fundamental)

Aimed to improve scientific theories for a better understanding of the natural world

Applied Research

Seeks to answer a question in the real world and to solve a problem

Facultative Symbiont

symbiotic partner that can complete its lifecycle without depending on another organism

Obligate Symbiont

symbiotic partner that cannot complete its lifecycle without depending on the other organism

Generalist Symbiont

able to thrive in/with a variety of hosts

Specialisti Symbiont

able to thrive in a narrow range of hosts

Horizontal (lateral) transmission

The acquisition of a symbiont is from another organism or the environment

Does strict horizontal transmission allow co-cladogenesis?

No!

Vertical Transmission

The acquisition of a symbiont from parent to offspring

Does strict vertical transmission allow co-cladogenesis?

Yes!

Eusocial Insects

* Cooperative care for immature individuals (broods)
* Overlap of @ least 2 generations in the same society
* Coexistence of reproductive and non-reproductive members

Natural Selection is the Consequence of…

* variation in traits
* differential reproduction (limits on pop. growth in the environment)
* Inheritance

Proximate Causes

(How do they do it? Mechanism)

* an event which is closest to or immediately responsible for causing some observed result

Ultimate Causes

(Why do they do it?)

* thought of as the “real” reason something occurred
* functions (adaptive values)
* Evolution (history of species)

Evolutionary Legacy

an organism’s future evolutionary trajectories may be constrained or biased by traits that it has already evolved

Ethology

The scientific study of the descriptions and prediction of behaviors (no experiments)

Animal behavior

The prediction and influence of behaviors tested with experiments

Behavioral Ecology

the study of behavioral interactions btwn. individuals within populations and communities, usually in the evolutionary context

Proximate Explanations

Mechanisms that causes particular pathology

Developmental Explanations

How pathology came about over the organism’s life course

Evolutionary Explanations

How natural selection and other evolutionary processes interact to leave the body vulnerable to a particular pathology

Phylogenetic Explanations

look at a species’ evolutionary history and explain where in this evolutionary history such vulnerabilities came about

Adaptation

A trait that increases an organism’s fitness and that is the result of the process of natural selection

Selection

a process where traits are selected for or against and became more or less abundant

Allele

variant forms of a gene that arise by mutation and are found at the same place on a chromosome

Stabilizing Selection

Genetic diversity decreases as the pop. stabilized on a particular trait value

Disruptive Selection (diversifying selection)

Extreme values for a trait are favored over intermediate values

Directional Selection (Positive Selection)

A single phenotype is favored, causing the allele frequency to continuously shift in one direction

* eventually a stage is reached where no further advantage is conferred

Artificial Selection

A process in which an organism selects for or against particular features in other organisms

Convergent Evolution

organisms not closely related, independently evolve similar traits as a result of having to adapt to similar environments or ecological niches

Phylogeny

evolutionary relationship among organisms

* gives evolutionary context
* provide framework for more specific questions
* allows us to describe the history of a trait as reconstructed from its phenotype and genotype

Phylogenomics

analysis that involves genome data and evolutionary reconstructions

Macroevolution

Grand Scale; what we see when we look at the over-arching history of life; change that occurs at or above the level of species

Microevolution

Small scale; change in allele frequencies that occur over time within a pop

Chronogram

indicated the timing of evolutionary events

Cladogram

Phylogenetic tree in which evolutionary relationships are represented but branch lengths do not indicate the degree of evolutionary divergence

Phylogram

phylogenetic tree in which length of each branch represents the amount of evolutionary change that has occurred along that branch

Homologous

Traits inherited from a common ancestor

Analagous

Traits similar because of convergent evolution

Cladogenesis

Splitting of a single lineage (parent species) into two distinct species

Coefficient of Relatedness

The probability that 2 related individuals have inherited a particular allele from a locus/gene from their common ancestor

Identical by Descent

Alleles that are shared because of common ancestry

Haplodiploidy

sex-determination system where males develop from unfertilized eggs (haploid) and females develop from fertilized eggs (diploid)

Size-complexity hypothesis

as larger colonies evolve, division of labor becomes more complex as workers and queens act to maximize inclusive fitness

Direct Fitness

expected # of viable offspring an individual produces

Indirect Fitness

\# of relatives produced multiplied by degree of relatedness to those individuals

Inclusive Fitness

Sum of direct and indirect fitness

Superorganism

A society, such as a eusocial insect colony, that processes features of organization analogous to the physiological properties of single organism

What is kin relatedness in a eusocial colony dependent on?

* # of reproductive females (monogymy/polygymy)
* Mating frequency (monoandry/polyandry)

2 Ways to maintain reproductive control

1. Worker policing - workers eat or remove eggs that have been laid by other workers
2. Nestmate aggression - workers attack egg laying sisters due to chemicals associated with fertility

Coevolution

Evolutionary change in 2 interdependent pop. of 2 species where the evolutionary modifications in one species drive modifications in the other

2 Basic Scenarios for Coevolution

1. mutualist interactions - evolutionary changes in each species benefit the other species
2. antagonistic coevolution - evolutionary changes in each species decrease the fitness of the other species

Cospeciation

Speciation in one species leads to speciation in another

Muller’s Ratchet

process by which # of deleterious mutations build up irreversibly over time in asexual pop.

Evolutionary Arm’s Race

evolutionary struggle btwn. competing sets of co-evolving genes, traits, or species, that develop adaptations and counter-adaptations against each other

Cheating

Increasing fitness of actor (above avg.) and decreasing the fitness of the partner (below avg.)

Microbiota

ecological community of symbiotic microorganisms that line on or in an organism

Microbiome

complete genetic content of microbiota

Holobiont

unit of biological organization compound of a host and its microbiota

Hologenome

complete genetic content of host genome, it’s organelle’s genomes, and its microbiome

Multilevel Selection Theory

selection operates across multiple levels of genetic variation with phenotypic effects

Partner Choice (PC) Model

Host select beneficial symbionts out of a pool of all symbionts therefore bringing about mutualism

Partner Fidelity Feedback (PFF) Model

Co-dispersal aligns the interests of 2 lineages and causes mutualistic behavior to evolve

Trophallaxis

Transfer of food/fluids through mouth-to-mouth or anus-to-mouth

Allogrooming

animals grooming each other

Coevolution-codivergence model

largely vertically transmitted btwn. ant generations

Acquisition Model

Pseudonocardia is part of a microbe community that colonizes the ant integument from environmental sources

Multimodel Signals

communication working through multiple sensory channels

Natural Selections

Based on ability to survive, gather resources, and reproduce

Sexual Selection

based on ability to mate with more or better partners

Signal

one individual (sender) in some way modifies the behavior of another (receiver) with acts or structures

Mate Choice (intersexual selection)

evolutionary process in which selection of a mate (most often male) is dependent on the attractiveness of phenotypic traits

How do we know that signals are evolutionarily stable?

there must be an average benefit for both senders/receivers

Cue

provides information to others but is a by-product of some other action and is not shaped by natural selection

Precursor route beginning with signaler

signals originate from traits (no function) that become specialized over evolutionary time to convey info more effectively

Precursor route beginning with receiver

recipients may have preexisting sensory biases that are independent of the given communication

Semiochemicals

any substance used in communication, whether btwn. species (symbioses) or btwn. members of the same species - heritable phenotypic traits

Types of honest semiochemicals

* males attracting a mate
* females attracting a mate
* bacteria releasing chemicals to coordinate cooperative behavior
* poisonous insects warn predators away with chemical glands
* nestmate recruiters

Pheromones

an exerted chemical compound that triggers a social response in members of the same species

Emery’s Rule

hosts and parasites are each other’s closest relatives (sister taxa)

Predation Hypotheses

Social parasites evolved from ancestors with predatory behavior