Lecture 19 Animals Flashcards
Mammals
- When did earliest mammal appear in fossil record
- When were they widespread and diverse
- When did they begin to diversify
- When did many mammal lineages happen-what was the result
- 195 MYA
- Mammals widespread and diverse by 165 MYA
- Began to diversify when dinosaurs and other reptiles were dominant large herbivores and predators in terrestrial and aquatic environments
- Lineages died out during Cretaceous mass extinction 66 MYA and lineages that survived underwent adaptive radiation
- Mammals definition
- Milk purpose
- What is a key feature of mamals
- Endotherms
- Mammals are a monopphyletic group of amniotes named for mammary gland which produce milk
- Milk nourishes developing young via lactation
- Only vertebrae with cheek muscles and lipis which make suckling milk possible
- Endotherms allows them to maintain high body temp by oxidizing large amount of food and generating large amount of heat (layers of hair/fur)
What are the 3 types of mammals
- Prototherians (monotremes such as platypus and 4 echidna species)
- Metatherians (marsupials like opossums, kangaroos, wallabys)
- Eutherians (placental animals and everything else)
- Placenta
- What does the embryo contribute
- What happens after development period
- Placenta is an organ combining maternal and embryonic tissues located inside the mother and nourishes embryo internally
- Embryo contributes to placenta- allantois and chorion which helps with diffusion of gases, nutrients, wastes
- After gestation, embryo emerges from mothers body
- What are the variety of methods of parental care
- What is extensive parental care
- Fanning aquatic eggs with oxygen rich water
- Guarding eggs and/or new young from predatos
- Keeping eggs and young moist (amphibians) or keeping them warm and dry
- Supplying young with food
- teaching survival skills to young
Mammals and birds provide extensive parental care which is energetically expensive to provide and can improve animal’s fitness
- Monotremata
- Maruspiala
- Monotremata- egg laying mammals (5 known species) and are oviparous
- Marsupiala- Pouch bearing mammals (350 known) and are vivaporous with simple placenta)
Eutheria
Eutheria are placental annimals with well developed placenta and extended pregnancy (5100 known species) and vivaporous
- What are the evolutionary advantages of viviparity and placenta
- What is the tradeoff of a placenta
Advantages:
1. Offspring develop at more constant, favorable temp
2. Offspring are protecting
3. offspring are portable, so mothers are not tied to a nest
4. Tradeoff: Placenta is energentically expensive to produce and bearing young is costly
What are the defining characteristics of primates?
What are the 2 important ones that is a synapormorphy of all primates
1. Hands and feet that are efficient at grasping
2. Flattenel nails instead of claws
3. Relatively large brains
4. Color vision
5. Complex social behavior
6. Extensive parental care of offspring
7. Forward facing eyes
Primates: Prosimians
- What are prosimians
- What do they include
- What are their main characteristics
- Before monkeys
- Lemurs from Madagascar, tarsiers, pottos, and lorises (Paraphyletic! but still grouped together)
- Small bodied, aboreal, noctural
Primates: Anthropoids
Anthropoids
1. What are they like
2. What do they include
- Human like
- Include new world and old world monkeys, gibbons, and the huminidae aka great apes which includle gorillas, chimps, humans
Are humans monkeys?
Monkeys are a grade. Which makes us monkeys
Hominds
- Characteristics of hominds
- What are the distinc\t ways of walking
- Are humans great apes?
- aka great apes have large bodies with long arms, short legs and no tail
- Orangutans fist walk, gorillas knuckle walk, humans are bipedal or 2 footed walking with 2 legs
- Yes
DId humans evolve from chimps
Drawing a phylogenic tree allows you to know they are sister groups that share an extinct common ancestor that was neither chimp nor human
What are the problems with the famous picture of gibbons to humans
- It imploes all steps lead to humans. All monkey species are just as modern as us
- Not a direct line of evolution, there are offshoots. They are our relatives but not direct ancestor
- Hominins
- What is a synapomorphy
- Is there linear progression
- What is a feature of homo compared to other hominins
- Which homo species are the sole survivors
- Hominins are a monophyletic group comprosing Homo sapiens are more than 20 extinct species. They are all bipedals
- Synapomorphy is bipedalism for hominins
- Many branches: no linear progression as multiple species live at one time
- The species “homo” had large brains compared to other hominins
- Homo sapiens are sole survivor of adaptation radiation of hominins
What is leading hypothesis of hominins of why there are larger brains
Early Homo began using symbolic spoken language and tools (trigerred natural selection for capacity to reason, plan, communicate; cooperate in complex social networks; favored larger brains)
Fossil humans
- What are the 4 general groups of hominins
- What is the oldest known hominin
- Gracile australopithecines
- Robust australopithocines
- Early homo
- Recent homo
Oldest hominin: Ardipithecus ramidus
- Gracile australopithecines
- robust australopithecines
- Gracile- composed of species of small hominins are were bipedal
- Paranthropus or robust- 3 known species had massive cheek and jaws, large cheekbones, sagittal crest which is a flange of bone at top of skull (Extinct)
- Homo
- What was the diagnostic trait of early Homo
- All species in genus Homo are called humans which have flatter and narrowwer faces, smaller jaws and teeth, larger brain cases
- Extensive toolmaking was a diagnostic trait
Homo naledi (where is most notable species, definition and traits)
- Most notable new species discovered in Africa
- Early humans with mix of traits
- General shape of skill moderns
- Braincase less than half the size of modern humans
- very young (less than 335,000 YO)
Recent homo
- What are the main species
- how long have they been alive
- What are some features of recent Homo compared to early Homo
- Homo sapiens and Neanderthals
- 1.2 mya to present
- Flatter faces, smaller teeth, larger braincases
Homo floresiensis
When were this discovered and what do they consist of
- Discovered in 2003 on island of Flores in Indonesia
- Consists of individuals who were a meter tall (hobbits) (190,000-50,000 years ago)
- Out of Africa hypothesis
- Did they evolve somewhere else?
- Did they migrate once or multiple times?
- Did they interbreed?
- Modern homo sapiens originated in africa and spread throughout the world.
- They evolved indepedntly of Earlier and Asian species of homo.
- Multiple waves of migration
- Interbred with Neanderthaals (about 5%)
