Evolution Flashcards
Master all
What is creationism?
A belief system that requires no proof.
What is EVOLUTION?
A SCIENTIFIC THEORY THAT REQUIRES PROOF.
Definition of Biological Evolution.
A gradual change in the genetic makeup of a population of an organism.
Two ideas were under examination by the society that Darwin lived in.
What are these ideas?
- Ancestry/Inheritance.
2. Fixity/Change.
Define natural selection.
Individuals with advantageous traits will tend to survive to reproduce. If those trusts are heritable then the composition of the population will change.
Define Adaptation.
Any characteristic of an organism that will improve its chance of surviving and reproduction. This can be Morphology (e.g.)Wings Behaviour(e.g.)Nesting site selection. Physiology (e.g.)body temperature.
Darwin’s theory of evolution proposed 4 factors which result in evolution and adaptation..
What are these Factors that Darwin Observed?
- Overproduction
- Limits to population growth
- Variation between individuals
- Differential reproductive success.
What is OVERPRODUCTION?
Each species produces more offspring then will survive to maturity
E.g. Cod Gadus sp.
1 lays 2-5 million eggs per year
Has External fertilization – No parental care
Enormous predation 50% survive–99% mortality first month
5 survive–90% of survivors don’t reach first year
Average 2 young per Pair survive to Childhood.
(Another example)💕🥳💕
Elephants
Describe LIMITS TO POPULATION GROWTH
Darwin’s proposed factors in evolution and adaptation
There are finite quantities of food water and space
Therefore individuals compete for these resources
More individuals are produced then the environment can support
Predation disease also cause mortality
Darwin’s 4 proposed factors of evolution
Describe variation.
Individuals in a population exhibit variation. Eh. Height, Hair, Skin etc
Some traits will improve on an individual’s chances of survival and reproductive success.
If this trait is heritage then it will be selected for.
Example of this…TWO COLOUR MORPHS.
Darwin’s proposed factors of everything
Describe differential reproduction.
Some individuals will have more offspring than others. Of these survive, then the overall fitness of that parent will be High.
Usually best adapted individuals survive and reproduce more.
(N.B) could use different social structure in Rhabdomus populations– Springbok vs. Irene. To highlight how an adaptation in one habitat could be advantageous but would be disadvantageous in another habitat.
Evidence to test models.
What are these?
- Comparative anatomy
- Molecular biology
- Vestigial structures
- Embryology
- Fossils
- Artificial Selection
Describe Comparative Anatomy..
Any two living species show some similarities.
These similarities are either
ANALOGOUS–Result of shared environment (convergent evolution)
HOMOLOGOUS– Result of shared ancestry(phylogenetic)
Additionally: Anologies aren’t evolutionary useful in terms of indication of common ancestry. (E.g. Sharks and Dolphins)
Homologies are evolutionary e.g. different organisms occupy a wide range of habitats and use limbs for a variety of functions. But they all share the pentadactyl limb plan.
Strong indication of common ancestry.
Please note
Evolution is conservative
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IT CHOSE YOU NKANYISO
Describe Molecular Biology
Homologies exist at the molecular lev and strongly support notion of common ancestry.
We look at DNA, Genetic Code and Histones (responsible for DNA packaging of proteins and are therefore highly conserved across kingdoms).
Describe Vestigial Structures.
Evolution says vestigial structures are Phylogenetic baggage. Inherited material that is no longer useful but has no cost, therefore not selected against.
Describe Embryology
Define Von Baer’s Third Law VS Enerst Haeckel Law.
Homologies are evident in rated embryos.
Von Baer’s third law stated that the gener features of large groups(e.g. spine of vertebrates) appears early in development
Vs
Enerst Haeckel–Stated that ontogeny decapitated phylogeny. As animal develops it goes through stages that resemble it’s lineage of common ancestors. To an extent this is true because the development of pathways are conserved.
Describe Fossils
The fossil record is patchy, intermediate forms are often missing but to be expected–chances of being preserved in the same place at a different time=almost zero.
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Yourself
Keep negative thoughts Away.
You’ve proven it may times that You’re Phenomenal. Everything u touched turned into Gold. You’re Great Nkanyiso.
And the Lord said “It is Done”
