Ecology and Natural Selection (Unit 7+8) Flashcards
What is a closed system?
Only energy can cross boundry
What is an open system?
Open to exchange of matter and energy across system borders
What is biota?
All living organisms in a particular enviroment
What does anthropogenic mean?
Human caused disruption to balance
What level is the first place abiotic factors are considered?
Ecosystems
What are detrivitors?
Decomposers (get energy from detris (non living matters))
What pyramid can be inverted?
Pyramid of numbers
What pyramid is always upright?
Pyramid of energy
How does size influence the metabolic rate?
As size decreases, metabolic rate increases (inverse relationship)
What are exotherms?
Organisms that use external/behavioral mechanisms to regulate their body temp
What are endotherms?
Organisms that use energy generated by metabolism to maintain body temp
What is evolution?
The change in genetic makeup of a population over time
What is natural selection?
The process by which organisms having adaptations suited for a particular environment have a greater chance of survival and reproduction, passing the adaptation into the next generation
What is productivity?
The rate at which an ecosystem can trap energy and turn it into biomass
What is the result of eurotrophication?
Overabundance of resources = overgrowth = dead zones
What is a niche?
An organisms role in their environment
What are limiting factors?
Ex nutrients
What is fitness?
The ability of an organism to survive and produce fertile offspring
What is range?
The geographical area where an organism is found
What is a habitat?
The abiotic and biotic features in a place within an ecosystem/biome
What is ecosystem stability?
It determines the rate and direction of evolution
(populations are less likely to evolve in environments that remain stable for long periods of time)
What is asexual reproduction?
Budding, cloning, etc
Plants (when in a successful environment)
What are structural adaptations?
Changes in structure to make the organism better suited to its environment
Ex. Camouflage, colouration, morphological features (ex changes in skeleton)
What are behavioural adaptations?
Things an organism does to survive, usually in response to external stimuli
Ex. Nesting, hibernation, migration, mating dances
What are physiological adaptations?
Changes in metabolism to maintain homeostasis
Ex. Breathing rate, skunks door production, digestive enzymes
What is genetic variation?
DNA variations among individuals of the same population
Sources: mutation, genetic recombination, genetic drift
How does phenotypic variation occur?
When variation of the bases (genetic variation), causes amino acid change
What is phenotypic variation?
Variability of phenotypes within a population (differences in observable appearance)
What is natural selection?
The process by which a population of organisms changes because individuals with certain traits can survive the local environment conditions and pass these traits onto offspring
What do selective pressures do?
Organisms with particular characteristics are either favoured or eliminated
Cause individuals with certain phenotypes to behave a better chance of survival and reproduction
What is fitness?
The ability of an organism to survive and reproduce
What is evolutionary fitness?
A measure of the average contribution to the gene pool of the next generation of an organism with a particular genotype/phenotype
What is descent with modification?
Species change over time, giving rise to new species that share a common ancestor
This explains organisms adaptations
Define evolution and what it needs to happen
Evolution causes populations to be better adapted to their environments over time
Depends on the environment and requires existing heritable groups
What is artificial selection?
Species modified by humans (selective breeding)
What is direct observation (evidence of evolution)?
Insect population s becoming rapidly resistant to pesticides (ex DDT)
Antibiotic resistant bacteria
What is the fossil record (evidence of evolution)?
Radioactive dating + law of superposition
Transitional fossils
What are homologous structures?
Similar structures, different functions
Indicates a common evolutionary ancestor
What are analogous structures?
Similar function, different structure
Does not indicate a common evolutionary ancestor
What is molecular homology?
Shared characteristics on a molecular level (DNA/RNA sequences)
What are vestigial organs (evidence of evolution)?
Ex tiny pelvis and leg bones in some snakes
What is convergent evolution?
The process by which distantly related organisms independently evolve similar traits
Analogous structures
What does biogeography mean?
How and why animals live where they do (geographic species distribution)
Ex South American desert animals are more closely related to other animals they live near than Asian desert animals
What are endemic species?
Species native to a particular region and only found in that region.
What a re introduced species?
Non native species
What are invasive species?
Introduced species that spread widely and cause harm
Why do species go extinct?
Climate change is faster than evolutionary processes
Low variability
What is a species?
A group of living organisms that can exchange genes/interbreed and provide viable and fertile young
What does evolution act on?
Populations
What is micro evolution?
Adaptations that are confined to a single gene pool (population of a species)
What is macro evolution.
Major evolutionary change within a whole taxonomic group (above species level)
What is speciation?
The evolution of a new species over time
If they can still interbreed, they are still the same species
What is gradualism?
New species slowly change over time from a common ancestor
(Think transformation)
What is punctuated evolution?
Period of stasis followed by rapid evolutionary change
Can be seen in sudden changes observed in the fossil record (divergence)
What causes speciation.
Reproductive isolation
What is reproductive isolation?
The existence of biological barriers that impede production of viable fertile young
What is post zygotic reproductive barriers?
A offspring is prevented from developing into a fertile adult
What is prezygotic reproductive barriers?
Happens before the egg and sperm meet?
What is genetic drift?
Random change in allele frequency in a population
What is allopathic speciation?
New species occurring because they are geographically isolation from the parent population
- interrupts gene flow causing reproductive isolation
Does their have to be geographic isolation for speciation to occur?
No
What is simpatic speciation?
A small part of the population forming a new species without being geographically isolated from the parent population.
How does simpatico speciation occur?
Part of the population may have switched to a new habitat or food source or there could be a mistake in cell division causing polyploidy (common in plants)
What is adaptive radiation?
Single common ancestor, highly branched into different species
These new species fill different ecological niches in their communities that often open up after catastrophic events/mass excitations
What is cladogenesis?
Evolutionary splitting of a parent species into two distinct species forming a class group of organisms from a common ancestor
What does cladogenesis result in?
Diversity. (Many species produced by few)
What is agenesis?
Gradual changes (transformation)
The lineage in a phylogenetic tree does not split
Dear King Philip came over for good soup
Domain, kingdom, phylum, class, order, family, genius, species
Explain Batesian Mimicry?
A lizard lacking a chemical defence mechanism that is coloured in the same ways as a lizard that has a defense mechanism.
What is aposometric colouration?
Colouring that indicates an animal is poisonous
What is cryptic colouration?
Colouring that acts as camouflage/disguse
What is Müllerian mimicry?
Two toxic organisms (both have defense mechanisms), look similar (so predatory avoid both
What is a gene pool?
The combination of all the genes (including alleles) present in a reproducing population or species
What is phenotypic frequencey?
The rate of occurrence of a particular phenotype in a population/gene pool
What is genotypic frequency?
The frequency of occurrence of a particular genotype
How are allele frequencies expressed?
As a decimal
What is Hardy Weinberg/Genetic Equilibrium?
A theoretical condition in which a populations genotype and allele frequency remains unchanged over successive generations (evolution is not occurring).
What are the requirements for Hardy-Weinberg Equilibrium?
- Large population
- Random Mating
- No net mutations
- No migrations
- No natural selection
p + q = 1
What are the 3 types of species distribution?
- Clumped
- Uniform
- Random
What are life history stratagies?
The pattern of survival and reproduction events typical for a population (a species life cycle)
What are k selected species?
S curve, stable environment
ex Humans and elephants
What are r selected species?
J curve, fluctuation environment
ex. bacteria, flies
What is environmental resistance?
Prevents a population from growing at its biotic potential and determines the carrying capacity of the habitat.
What is carrying capacity?
The maximum # of individuals that an ecosystem can continually supply resources to/support
What is biotic potential?
The maximum growth rate of a population given unlimited resources, space, and lack or competition or predators.
What are density dependant limiting factors?
Limiting factors that is closely tied to population size
ex. Disease, food supplies
What are density independent limiting factors?
Not related to population size
ex. Natural disasters, weather conditions
