Evolution and Ecology Flashcards
The entirety of Sem 2
What is evolution?
The total environment determining the reproductive success and survival of species, leading to change in allele frequency.
What are the 5 ways we study ecology?
- Observation
- Surveys
- Correlations
- Experiments
- Models
What is a metapopulation?
A single population that occurs in fragmented habitats connected by limited migration. Lots of extinction and recolonisation.
What is the Lincoln Index equation?
N = M (Marked individuals released) x S (Size of second sample / R (Marked animals recaptured)
What is a stressor?
An environmental factor that inhibits growth and reproduction.
What is stress?
The physiological resultant of demands that exceed an organisms capacities.
What is Shelford’s Law of Tolerance?
Species distribution is controlled by the factor which the species has the narrowest range of tolerance too.
What law is Shelford’s law based on?
Liebig’s law of minimum, stating that the rate of biological process is limited by the factor in the least amount.
What is acclimation?
A response by an animal or plant that enables it to tolerate a change in a factor in its environment.
What is acclimatisation?
Reversibly adaptive response that enables animals or plants to tolerate environmental change involving several factors (E.g. Hibernation)
What is adaptation?
Evolutionary processes through natural selection that changes the tolerance of a species.
What is the epilimnion?
Warm, low density surface waters.
What is the thermocline?
Zone of rapid temperature change in water.
What is the hypolimnion?
Cold high density deep water.
What is the proximate study of a trait?
How the gene works and how it is achieved. Mechanism that underpins the trait and explaining the biological function (like genes)
What is the ultimate study of a trait?
The consequences of a trait and if it is selected. Study of traits in terms of the evolutionary forces acting on them. (Such as colour for poison)
What did Jean Baptiste Lamarck believe in?
- Traits and behaviours change (correct, evolution)
- Moving to human perfection (incorrect, self explanatory)
What is fitness?
Measure of an organisms ability to produce viable offspring in comparison to others.
What are the three types of selection?
- Directional
- Disruptive (can cause adaptive radiation)
- Stabilising
What is the equation for total phenotypic variance?
Vp= Vg + Ve
g = variance due to genetic effects
e = variance due to environment
What is heritability of a trait?
The proportion of observable differences between individuals within a population due to genetic differences.
What is the equation for heritability?
Vg/Vp
What is Mendel’s first principle?
‘Principle of Segregation of Unit Characters’
- 2 of more phenotypes conferred by the same gene are an allele.
What was Mendel’s second principle?
The principle of independent assortment.
What are the two types of variation?
Continuous: Many genes, high environmental influence and no discrete morphs (leaf size)
Discontinuous: few genes with low environmental influence. Few discrete morphs (patterns on spider bodies)
Give a summary of the Cambrian explosion.
- 565 mya, marked by the first tracks of bilaterian.
- All major phyla appear
- First stage of the Phanerozoic
There is a possibility that there were diverged phyla beforehand and the explosion is due to a change in bio/marine chemistry that led to fossilisation.
What are some of the biological causes of an extinction?
Being outcompeted by another species, disease.
What are some of the non biological causes of an extinction?
Asteroids, any change in abiotic factor, tsunamis and earthquakes, volcanic eruptions, change in the atmosphere, water levels changing.
What are the big 5 extinctions?
Cretaceous, Triassic, Permian, Devonian, Ordovician.
Name the date, impact, and cause of the Ordovician extinction.
Date: 439 mya (440)
Impact: Extinction of 1/4 of marine families (Bivalves, echinoderms, corals, trilobites)
Cause: Decrease in sea levels due to glacial formation
Name the date, impact, and cause of the Devonian extinction.
Date: 364 mya (360)
Impact: Extinction of 1/5 of marine families (Trilobites, ammonites, reef builders)
Cause: Unknown
Name the date, impact, and cause of the Permian extinction.
Date: 251 mya (250)
Impact: Extinction of 95% of all species (Ammonites, trilobites X_X, echinoderms, insects, brachiopods)
Cause: Volcanic eruption/asteroid
Name the date, impact, and cause of the Triassic extinction.
Date: 207 mya (200)
Impact: Extinction of 1/2 of marine families (conodonts X_X, reptiles, amphibians)
Cause: Undersea volcanoes
Name the date, impact, and cause of the Cretaceous extinction.
Date: 66 mya
Impact: Dino’s dead, extinction of 1/2 of major groups of marine species (ammonites X_X, dinosaurs X_X (other than birds), pterosaurs X_X, plesiosaurs X_X, plants)
Cause: Asteroid
What is coevolution?
A change in one gene in a species stimulates an evolutionary change in one gene in another species. This causes another change in the first species and the cycle repeats.
What are the two types of coevolution?
Mutualism - Both benefit
Commensalism - One benefits, the other doesn’t lose.
What are the three types of coevolution that does not result in an arms race?
Plants and:
1. Pollinators
2. Dispersers
3. Herbivores
What are the two types of coevolution that result in an arms race?
- Hosts vs parasites/pathogens
- Prey and predators
Describe the Red Queen Hypothesis.
To evolve as a species, the prey must be constantly evolving so that the predator can never catch it.
Describe the sequence of an arms race.
- Parasite reduces fitness of host
- Host increases fitness via mutation/recombination, and this trait spreads
- New mutant/recombination appears in parasite species, spreads in population.
What types of mutation might occur in an arms race?
- Colouration change
- Protective armour
- Chemical defence
- Mimicry
- Behavioural change
What are the three types of defensive colouration?
Cryptic: Blending into the background
Masquerade: Object resemblance, distracting attack away from most vulnerable part
Aposematic: Bright, ‘oh shit thats poison’ colours
What are the two types of mimicry?
Batesian: Both species toxic, reinforced message.
Mullerian: One is toxic, the other isnt.
What are some behavioural mutations that may occur in an arms race?
Deimatic (Intimidating), Thanatosis (fake death), Retaliation, Fleeing