Intro and Evolution/Speciation Flashcards
What is ecology?
- interaction between organisms and the biotic and abiotic components of their environment
Examples of non-living and living aspects of an environment
Non-Living: landscape, climate
Living: fauna, flora, vegetation
Aspects of an environment:
- Biome (ex: forest)
- Place in that biome (ex: leaf litter)
- Microenvironment (ex: under deciduous leaves)
Ecological Hierarchy (from biggest, to smallest)
- Global
- Landscape
- Ecosystem
- Community
- Population
- Organismal (individual)
Global ecology
- Entire biosphere as a global ecosystem
- Regional exchange of energy and material influences across the globe
Landscape ecology
- Mosaic of connected ecosystems
- River ecosystem, forest ecosystem etc. connected…
- Focus on the factors that control the exchange of energy material and organisms across these different ecosystems; ex: to what extent does this forest along the river provide a corridor for the dispersal of terrestrial animals
Ecosystem ecology
- the community of organisms in an area and the physical factors with which they interact
- Communities of biotic organisms interacting with their abiotic
- Focus on energy flow and chemical cycling between organisms and environment
Community ecology
- community is group of populations of different species in one area
- examines interactions between species (predation, competition)
Population ecology
- Population is a group of individuals of the same species in same area
- Looks at population size and how life changes through time
Organismal
- Individual/autoecology
- Several sub-disciplines (physiology, evolutionary, behavioural)
- How a specific organism’s structure, physiology, behaviour met the challenges of their environment
- individuals capacity to adapt and meet challenges of environment
- individual organisms and abiotic and biotic components of their environment
What is individual?
- System made up of genetically identical cells that can communicate, and that have a common purpose or can at least coordinate themselves
- There are cases where a system of clones is indistinguishable from one individual (ex: Pando is an Aspen root and Honey Fungus largest individual organism)
Exceptions to an individual
- Chimera
What is a Chimera?
- a single organisms composed of cells from different DNA
- Due to: merging of multiple fertilized eggs in animals (twins, litters) or organ transplants
Example of chimera? (monkey and in human)
- Mamoset monkeys (95%)
- why? theory that help allocation of parental care
- XX/XY mosaic
How do individuals interact with their environment?
- Genetic adaptations (generations - long term)
- Phenotypic plasticity (Days-years)
- Regulation/Behaviour (seconds - hours)
Genetic adaptation
- Principles of the Theory of Evolution
- Variation
- Heredity
- Natural Selection
- Survival of the fittest
Example of the evolution of tetrapods
Evolution from bony, lunged fish
• Possible because
– Individual fish showed a wide range of
variation in limb size/strength
– This variation was genetic
– There was variation in reproductive success
associated with limb strength/length
– Those with stronger/longer limbs had greater
survivorship and reproductive success, and
thus were more likely to pass on their genes
How to study genetic adaptation?
- falsifiable hypothesis
- A posteriorir: after the fact; correlation between a trait and an environment; comparison of related species in different environments OR genetic comparison of individuals within a species
- A priori: ahead of time; experimental alteration
Speciation
- process by which one species splits into 2 or more species
- responsible for the diversity of life
- explains not only differences but similarities between species
- formation of a new species depends on reproductive isolation- biological species are not defined by similarities or differences in features, but by reproductive compatibility
Types of speciation
- Allopatric
- Peropatric
- Parapatric
- Sympatric
Allopatric
- geographic separation
- usually cause by a barrier
Peripatric
- small population becomes isolated
- Founder effect: genetic structure of the population will depend on the structure of the few individuals who founded the population
- Genetic Drift: genes rare in the main population become more common in the isolated population, until they eventually lead to speciation
Parapatric
- Partial geographical separation of parts of the original population but selection against heterozygotes
- Ex: ring species around the Mohave desert, no geographical barrier separates these species
Sympatric
- no geographical separation
- theoretically possible if there are divergent responses to the same selective pressure in the same place, but few examples
- thought to have been found in blind more rats that live at different depths but this could be seen as a geographical separation, so maybe more likely to be parapatric
