Modifications Of Basic Body Plans Flashcards
Alfred Russel Wallace
Helped find the modern science of biogeography
Descent with modification
Biological evolution
The process of change by which new species develop from pre-existing species over time
What natural barriers prevent organisms from moving freely from one region to another
Impassable topography
Large bodies of water
Unsuitable climate
Pentadactyl limb
Had 5 digits
Found in all four classes of terrestrial vertebrates
Local diversification by specialisation
The forming of new species and the dispersal of those species in a biogeographical region
Biogeography
The study of living organisms all over the world
Evolution
The change in genetic composition of a population
Mammalian forelimbs in primates- Monkeys
Opposable thumb to increase manual dexterity
Elongated phalanges to grasp and swing
Primates
Highest order of mammals with characteristics such as hands for grasping, binocular vision and enlarged brains
Ungulates- hoofed animals- horses
Quadrupedal locomotion to maximise stamina
Short humerus and muscle groups being located close to the body to increase acceleration
Elongated lower leg segments to increase stride
Mole
Short forelimb
Spade like paw
Nail like claws
Robust metacarpals and phalanges to give strength to paw
Whale
Pectoral flipper for keeping equilibrium whilst swimming
Short humerus, radius & ulna
Long metacarpals and phalanges for broad paddling
Bat
Short humerus
Long slender radius
Reduced ulna
Elongated metacarpal and phalanges to stretch wing frame for flight
Hook like fists
Vestigial structures
Structures removed/ completely lost due to the function they once performed no longer being relevant
Examples of vestigial structures
Pelvic girdle of a whale
Reduced coccyx
Human appendix
Difference between monkeys in Africa and in Southern America
Africa- narrowed noses
SA- broad noses & prehensile tails
Pangaea
Single land mass made of all the continents of the earth
Laurasia
Northern Landmass
Gondwanaland
Southern Landmass
Terrestrial biogeographical regions
Palearctic (Eurasia)
Neotropic (SA)
Afrotropic
Australasian
Indomalayan
Oceanic
Antarctic
What are marsupials
Begin life in the uterus but leave to enter marsupium while still an embryo
What are Placental mammals
Animals with a placenta connecting the foetus within the uterus to the mother’s circulatory system
Dispersal
The movement of population away from their point of origin
Biogeographical distribution of species
Single centre of origin
Passive/ active dispersal
Extinction of ancestors
Isolation from ancestors by barriers
Colonisation and adaptation of new areas by separate populations
New species are formed
What are Ratites
Large flightless birds
Different types of ratites
Extinct- Moa
Extant- Ostrich, Emo & Rhea
Physical characteristics of ratites
Flag sternum
Small wings
Heavy leg bones
Large bodies
Strong & thick feet
