Evolution Flashcards
Stages of chemical and Biological Evolution
Stage 1:
a. Early Earth
b. Inorganic molecules
c. Small organic molecules
Stage 2: Macro-molecules
Stage 3: Protocells (not able to divide)
Stage 4: Living Cells (able to divide)
Small Organic Molecules
Story of creation: There was a lot of energy present, causing the gasses to react to create the small organic molecules.
Function: These small organic molecules joined together to form macro molecules
RNA First hypothesis vs Protein First hypothesis
Both try to deepen the understanding of the formation of DNA.
RNA first hypothesis hypothesizes that RNA came before proteins.
The Protein first hypothesis hypothesizes that protein came before RNA.
Protocells
- Metabolic but can´t divide
- Heterotrophic (use other small molecules as food source)
- Hypothesized that lipids combined (when in a solvute solution) to create protocells
Baby Earth´s Atmosphere
- atmosphere was present, and composed mostly of gasses (including nitrogen, carbon dioxide, hydrogen, and water vapor)
- no oxygen at this time
- high in temperature. cooling of the atmosphere caused water to go from gas to liquid (rain fell, and so began the formation of the oceans, other bodies of water)
Lipids
- When lipids form (they do so through solutes) they create plasma membranes
Living Cells
- Are able to divide
Two Important aspects of biological evolution
- Common Ancestor
- Adaptation to the enviornment
Mechanism of Biological Evolution
- Natural selection
Natural Selection
- Decent with modification
Lamark
Hypothesized that characteristics are acquired over time (is wrong because acquired characteristics are not passed on)
Darwin
- Hypothesized that desired characteristics are selected for
Critical Elements of Natural Selection
- Variation
- Competition for limited resources (the ability for a species to expand is infinite but the resources that the species needs to flourish is limited)
- Adaptation
Evidence of Evolution: Fossils
- Fossils (hard tissues mineralize in sediment. Sedimentation creates layers/strata which helps with dating). Fossil Records tell us that simple organisms came before complex organisms
Evidence of Evolution: Biogeographical
- Distribution of plants and animals
- Evolution before migration
Evidence of Evolution
- Fossils
- Biogeographical
- Anatomical
- Embryology
- Biochemical
Evidence of Evolution (Anatomical)
- Common descent explains anatomical similarities
- Homologous structures (parts that share ancestors but serve different functions) are anatomically similar
- Analogous structures: (have the same structure but different ancestors)
Evidence of Evolution (Embryology)
- Closely related organisms have similar embryos
Evidence of Evolution (Biochemical)
Universality of:
- Genetic code
- DNA
- ATP
- Enzymes
3 domains of life
- Bacteria (single-celled prokaryotic cells)
- Archaea
- Eukarya
Classification of humans
Humans are primates
Characteristics of Primates
Adapted to living in trees, mobile forelimbs/hind limbs, grasping hands, flattened face, binocular vision, large complex brains, reduced reproductive rate
Humans vs Chimps (closest living relative)
Human:
- spine exits from centre of the skull, because we are upright beings
- spine is more S shaped
- pelvis is bowl shaped
- arched foot
- knee is more supportive
Chimps:
- spine exists at the rear of the skull
- spine is C shaped
- pelvis is narrow
- flat foot
Hominid
- Apes that are still living (gorilla, orangutan, chimps, and humans) and extinct Relatives
def: – the group consisting of all modern and extinct Great Apes
Hominine
- includes gorillas, chimps, and humans
def: of, relating to or characteristic of humans
Hominin
- Members are homogenus
Determinations of early humans of the human line
- bipedalism
- flatter face
- dull canines
- Brain size
Sahelanthropus
- very early hominds
- not sure if they were bipedal
- thick tooth enamel
- discovered in africa
- small brain size
- small canines
Orrorin
- limbs that suggest bipedalism
- large pointed canines
- very early homind
- discovered in africa
- fingers that are good for tree climbing
Ardipithecens
Two different species that have yet been discovered (A. kadabba and A. ramidus)
- small canines
- small head
- discovered in Africa
- very early hominid
- ape-like muzzle
- heavy eyebrow ridges
- opposoble big toes
- legs suggest bipedalism, toes suggest living in trees
Australopithecines
- early hominids
- species that gives rise to the homogenus
- What Lucy was
- Thought to be bipedal
Members of the Homo Genus are determined by:
- Brain size > 600 cc
- Jaw and teeth like those of humans
- Evidence of tool use
Homo Habilis
- early homo species (hominins)
- small teeth
- omnivore diet
- Tools (H. habillis= “handyman”)
- discovered in africa
Homo ergaster
- larger brain
- flatter face
- fire
- tools
- africa
Homo erectus
- Aisa
- Possibly originated in Africa; migrated to Asia and Europe
H. neandertalensis
- Europe
- Large brow ridges
- Protruding jaw, teeth, nose,
- Long pubic bone
- Larger brain
- Larger muscles
- Fire and tools
- Burial of the dead
Cro Magnon
- Earliest modern Homo sapiens: Cro- Magnon
- Migration to Asia and Europe from Africa
- Modern appearence
- Advanced tools
- Culture
- Language
- Art
Out of Africa Hyphothesis
- Humans originated in Africa, and migrated later
Human Variation in Ethnicities
- Adaptations to the local enviornment
- Some variation have no known benefit to local enviornment (ex. hair texture, upper eyelid folds, lip shape)
- More genetic vation within ethicities than between
Evolution of Hominins Time line
Ordered from when they started
~7-6MYA Salanthropus tchandensis ~5.5- 4.5MYA Ardipithecus ramindus ~4-3 MYA Australopitecus afarensis ~3-2 MYA Australopitecus africanrus ~2.25-1.5 MYA Paranthropus boisei ~2-1.5 MYA Australopitecus sediba ~ 2-1.5 MYA Paranthropus robustus
Order of Evolution of Different Organisms
- Prokaryotic cells
2a. Protist (single-celled organisms) - Eukaryotic cells
Prokaryotic cells
Lack a nucleus
Eukaryotic cells
- Have nucleus and membrane-bound organelles
- First Eukaryotic cells were single-cell protists, which gave rise to multicellularity and other kingdoms (fungi, plants, and animals)
Three characteristics that determine if a fossil is a hominin
- Brain size
- Bipedalism
- Flat face
On what continent are all early hominids found?
Africa
Out of Africa hypothesis
Hypothesizes that the humans originated in Africa and later spread across the world.
Human variation in ethnicities
- Humans ethnicities among population comes from adaptations from the enviornment
- ## More variety within a race than between
