Lecture 11: Ecology Flashcards
Community Ecology
Study of the interactions between species in communities.
Includes the study of the distribution, structure, abundance, demography and interactions between coexisting populations.
What constitutes a community and size of its territory is open to debate.
Interactions between Species
Different species within a community can interact with each other.
These interactions classified by ecologists: Competition
Predation
Symbiosis: parasitism, mutualism & commensalism
Facilitation.
Interactions between Species: Competition
Interspecific competition: When different species compete with each other over finite resources.
The species can compete for food, habitat, sunlight etc.
If 2 species occupy same niche, one will die.
Ecological Niche
Ecological Niche: sum of a species’ use of the biotic and abiotic factors in its environment.
Species way of life.
Analogous to a species’ job.
Ecological Niche Modeling
Hard to determine where a species is and where it likes to live.
Combine the observations of a species with abiotic date (temp, altitude, rainfall)
Use an algorithm to build a model of the tolerances of the species and fine its niche.
Organisms Occupying the Same Niche Can Evolve the Same Traits
Convergent Evolution
Predation
When one species eats another species.
Predator doesn’t always kill the prey or always consume the entire living organism.
Inclues Herbivory: eating of plants and algae.
Overlaps with parasitism in the case of parasitoids.
Predation and predator defense drive evolution in many organisms.
Predator Adaptations
Teeth, claws, speed, patience, venom, smell, vision, echolocation, camouflage, social behavior, etc…
Anti- Predation Adaptations
Mimicry, camouflage, poison, detachable tails, speed, smell, vision, social behavior, thorns…
Evolutionary Arms Race
It’s a fight between competing sets of co-evolving organisms or genes that develop adaptations and counter- adaptations against each other.
The war can be fought between predator and prey or parasite and host.
Co-Evolution
Joint evolution of two interacting species, each in response to selection imposed by the other.
Can occur at the species level or the molecular level.
Occur in predator/ prey, host/ parasite, and mutualistic relationship.
Darwin wrote about it.
Warning Coloration
Anti-predator adaptation.
Advertising that the potential prey tastes bad or is poisonous.
Coloration can be mimicked by other organisms.
Mimicry, Camouflage
Mimicry: Similarity of one species to another conferring an evolutionary advantage to one or both species.
Camouflage: When a species resembles its surroundings
Can be visual, aural or olfactory.
Interactions between Species: Symbiosis
An ecological relationship between two different species that live together in direct contact.
Can be bad for one of the species.
Types of Symbiosis: Parasitism, Mutualism and Commensalism
Symbiosis: Parasitism
Symbiotic relationship where one organism benefits at the expense of other.
Parasite lives either on (ectoparasite) or inside (endoparasite) of the host and feeds on cell components, tissues or body fluids.
Parasites don’t usually kill the host as this would deprive them of a host.
Symbiosis: Parasitism- Parasitoids
Live attached to or within a single host organism in a parasitic relationship, but eventually sterilizes or kills, and sometimes consumes the host.
Insects are most famously parasitoids, but other arthropods, prokaryotes, vertebrates and even plants can be parasitoids.
Parasitoid Wasps
Adult, Adult ovipositing egg into fly pupa, egg inside fly pupa, larva, pupa, adult emerging. = Adult.
Symbiosis: Mutualism
Symbiotic relationship where both organism benefit.
Symbiosis: Mutualism: Mycorrhiza
Mycorrhiza is a mutualistic association between a fungus and the roots of a vascular plant.
95% of plants have mycorrhiza.
Sometimes these associations are pathogenic
Symbiosis: Commensalism
A symbiotic relationship where one organism benefits and the other is neither harmed nor helped.
Some relationships appear commensal but are not when viewed more carefully or are not commensal for all members of the population.
Symbiosis: Commensalism Example?
Remora fish hitchhike on large organisms.
Sometimes they clean the larger organisms’ teeth and eat their poop.
Sharks have observed eating remoras attempting to attach onto them.
Demodex
Mite that lives in human hair follicles.
Not everybody has them but most do.
Considered to be a commensal skin organism.
Can cause skin problem in some people (acne)
They eat your skin cells and oil.They mate, lay eggs, defecate and die in hair follicles. Crawl out at night.
Lichens
Symbiosis between fungi and algae or bacteria.
Associations can be mutualistic, commensal or parasitic depending on species
Endosymbiotic Theory
Endo= with, Sym= together, Biosis= living.
Several eukaryotic organelles were originally free living microorganisms.
They now live with Eukaryotes in symbiotic relationship.
Secondary endosymbiosis have occurred.
Facilitation
An interaction where one species has a positive effect on the survival of another species without the intimate association of a symbiosis.
Some plants may make it easier for other plants to grow in the area.
