EVOLUTION Flashcards
what are the 6 classifications of locomotion
- scansorial = adapted for climbing (ground + trees)
- arboreal = tree-living
- terrestrial - ground
- ambulatory = not specialised (slow)
- cursorial - specialised for speed
- saltatorial = bounding/hopping
what are adaptations of climbers (scansorial + arboreal)
- propulsion on discontinuos + 3D substrate
- avoiding falling (grasping mechanisms)
- small and light
- balancing mechanisms - tail - heavy
what are some grasping mechanisms
flexor muscles, opposable thumbs, long digits, prehensile tail
what are some propulsion mechanisms
- flexed limbs with a low centre of gravity
- leaping and springing -> long and skender legs
- flexible spine
- Brachiation - arm swinging (long and thin arms)
what is gait
how limbs move e.g. walk vs run
features of cursorial animals
- travel far and fast
- speed and endurance
- acceleration and manoeuvrability
- increased speed = reduced manoeuvrability
what is bipedalism and advantages
movement via two rear limbs -> centre of mass is positioned over lower limbs
ADS:
- efficient
- raises head = wider range of vision
- free hands for tool use
- reduces protrusions away from body -> body weight distributed evenly
Bipedal adaptations for efficiency
- stride length requires leg springs and long legs
- energy storage - long calcanea tendon, plantar arch
- skeletal strength - stress reduced by extended (shock absorption)
- stabilisation - large glutes, neck muscles
what is a phenotype
visible characteristics expressed
what is a genotype
code for characteristics
what are the 5 main ideas of darwinism
- perpetual change
- common descent
- multiplication of species
- gradualism
- natural selection
explain perpetual change
- varying forms of organisms undergo measurable change over generations and time
- documented via fossil record
- changes may be in response to environmental changes
explain common descent
- all forms of life descend from a common form of life through branching of lineages
define phylogeny and how it is useful
- pattern of relatedness between different species
- basis for taxonomic classifications
explain multiplication of species
- origin of organic diversity
- species multiply by splitting into daughter species or by ‘budding’ (establishment of geographically isolated founder population that evolve into new species)
Explain gradualism
slow gradual changes over time
Explain natural selection
DEF: theory that organisms best suited to survive will live to reproduce, passing on favourable characteristics to the next generation
- surviving individuals pass on well adapted inheritable characteristics
- caused by competition for reproduction and survival
define evolution
- when heritable differences in a population become more common or rare over generations
define adaptation
An inherited trait that promotes survival and reproduction for a species - becoming better suited to an environment
what are the principals of natural selection
- variation must exist in population
- traits are inheritable
- more offspring produced than survive
- offspring of parents with advantageous trait are more likely to ave trait too = differential reproductive fitness
define species
a group of organisms capable of reproducing to produce fertile offspring
define random genetic drift
random fluctuations of allele frequencies within populations across generations caused by random chance events
define adaptive radiation
environment changes drastically causing many variations of one common ancestor e.g. volcano
define sexual selection
the selection of traits that are advantageous for gaining a mate but aren’t necessarily advantageous for survival
define artificial selection
the selective breeding of organisms by humans to enhance specific traits
convergent vs divergent evolution
convergent - organsims evolving to a common environments similarly without a common ancestor
divergent - common ancestor but evolve differently in different environments
what is co-evolution
frequency of many genes of a species changing in freq at same time (fast)
