extreme biology lecture 5 - adaptations by animals Flashcards
how do humans drive adaptations to animals?
-climate change
-pollution
-habitat fragementation
-hunting/harvesting
what is habitat fragmentation?
Processes in population biology are affected by habitat patchiness (fragmentation)
-Low degrees of fragmentation and high connectivity = good
-Small and isolated populations = bad
Effects are magnified over time
Will affected species differently
Can be grouped into two main categories
1- Specialist species
2-Generalist species
why are carnivores vulnerable to habitat loss?
-Carnivores are vulnerable to habitat loss
- lower population densities
-Require large home ranges
-Often persecuted by humans
what are linear features and their negative and positive effects?
Roads, fences, pastures, powerlines
Negatives=
-restrict movements
-Increase mortality
-Increase hunting and/or poaching
-Increased stress from visual and noise stimuli
Positives for some=
-Carnivores
-Facilitate travel
-Forage further and faster
-Trap prey on edges of habitats
-Scavenging on roads
what are the effects of hunting and harvesting?
Evolution of wild populations can be impacted by harvesting
leads to changes in:
Morphological
Behavioural
Life history traits
-Natural selection bring local adaptations to the natural environment.
-Selective harvesting impedes adaptive evolutionary processes
-Potential delay in the recovery of populations
why have African elephants been hunted?
-Sustained size selection on vertebrate populations = shift in age structure
-Traits targeted by hunters positively correlated with age
-African elephants (Loxodonta africana) are of particular risk
Disproportionally affected - older ages classes and males have larger tusks
Poaching is the driver - contemporary tusk evolution in African elephants?
are elephants compounded by habitat fragmentation?
Contemporary elephants are at lower densities
No foraging limitations
data supports shoulder height was higher in contemporary elephants
what are the 4 ways that species are vulnerable to climate change?
- exposure
- sensitivity
- resilience
- adapt
Typical rate of niche evolution (500 species) is 10,000 X SLOWER than the rate that is required to keep up with climate change projections
what are the options to deal with climate change?
1- Shift in range distribution within climate tolerant limits
2- Remain and adjust
i.Genetic composition
ii. Phenotypic plasticity
3- Extinction
i. Local level
ii.Global level
what is the shift in range?
-Rapid shift in environmental stability challenges the adaptive nature of marine mammals
- Species that rely on the ice are particularly vulnerable
what are the Resilience scenarios in 3 ice related categories
Ice Obligate
Ice associated
Seasonally migrant
what are the Seasonal migrant adaptions to Climate Change?
-Expend their geographical range
-Will benefit from net loss in sea ice
- Scoring of resilience to change through adaptation (or not…)
- Chukchi region scores the highest for resilience for seasonal migrants
-Seasonal migrants can adapt to their changing environment – generalist species
what is genetic composition?
-Micro evolution = Heritable shifts in allele frequencies in a population
- Morphological features
-In relation to climate change is coat colour
whats an example of changing genetic composition?
-Pelt colour in springbok (Antidorcas marsupialis)
Thermoregulatory significance
-Black springbok reduce their metabolic costs when it is cooler
-Black absorbs solar radiation more efficiently
Trade off during periods of high heat
what is phenotypic plasticity?
Phenotypic plasticity= where a single genotype gives rise to different phenotypes in different circumstances
Epigenetic effect
The animal itself changes not future lineages in response to environmental change
In response to climate change:
-Acclimation
-Acclimatization
-Learning
