Lecture 2: The The theory of evolution by natural selection + The chromosome theory Flashcards
What theory “where do organisms come from?”
The theory of evolution by natural selection
What explains that:
1. All species were created seperately // they are unrelated to one another
2. Each species is unchanging, + there is little variation
HINT: before Darwin (mid 1800s + earlier)
The prevailing paradigm special creation (aka natural theology)
DEF: What is a distinct, identifiable type of organism?
Species
Who discovered fossils for life forms that no
longer existed? (NOT RLLY NEEDED)
Early paleontologists (such as Mary Anning, 1799-
1847
- claimed that species could go extinct was met with
lots of resistance
In 1858, Charles Darwin + Alfred Russel
Wallace made what 2 claims regarding the natural
world: CD
- All species are related by COMMON ANCESTRY
- Characteristics of species can be modified from gen to gen (DESCENT W/ MODIFICATION)
Descent w/ modification further explained (2 points):
- Species changing overtime= MICROEVOLUTION
- Species splitting + diverging= MACROEVOLUTION
What is defined as:
- A change in the characteristics of a POPULATION over time
- Species are related to one another and
can change through time
Evolution
What is defined as:
– A group of individuals of the same species
– Living in the same area
– At the same time
Population
Darwin was the first to what?
The first to find a lot of evidence to back up the idea that species were unchanging
Which 2 people proposed the mode of evolution of NATURAL SELECTION?
Darwin +Wallace
2 conditions of Natural selection:
- Individuals must vary in traits that are HERITABLE (can be passed on)
- In a specific environ.- certain versions of heritable traits help individuals reproduce more than other versions
What happens if certain traits lead to increase success in producing offspring?
These traits become more common in the pop. over time (evolutions is a result of natural selection)
Natural selection acts on ____
Individuals
Evolutionary change occurs in ____
Populations
DEF: What occurs when populations diverge to form new species?
Speciation
Ex. Daphinia spp. example
Lake w/o out predators have no spine + lake w predators have spines
What is defined as:
- The ability of an individual to produce offspring
Fitness
Individuals w high fitness produce many ____ offspring
surviving
What is defined as:
- A heritable trait that increases the fitness of an individual in a particular environ.
Adaptation
Natural selection ex.
Explain Finches on a Galapagos island
- Variation in finch beak size +
shape - Rainfall consistent=
small soft seeds are
abundant - Shift in the proportion
of finches with small, pointed
beaks
Small pointed beaks:
- have a higher fitness (produced more offspring
- heritable (genetic basis)
- adaptation (increased finches ability to thrive)
- increased in pop.)
T or F
True
The _____ is the fundamental structural unit in all organisms
Cell
All species are related by common ______ + have changed over time in response to _____ ______
Ancestry, Natural Selection
What theory explains “How is hereditary information transmitted from one generation to the next?’
The chromosome theory of inheritance
Who proposed the Chromosomal theory of inheritance in 1902
Walter Sutton + Theodor Boveri
Chromsome Theory:
- Hereditary or genetic information is encoded in ____
- Genes are units located on ______
Genes, chromsomes
1950s: CHROMOSOMES are molecules of _____ (deoxyribonucleic acid)
DNA
DNA is hereditary material T or F
True
Genes are segments of DNA that code for cell products T or F
True
DEF: what described the flow of information in cells
The Central Dogma
DNA codes for ____ (ribonucleic acid) which codes for ______
RNA, protein
RNA copy made of the DNA’s info T or F
True
The RNA copy read to determine what ____ _____ to use to make a protein
Building Blocks
DNA is copied to pass genetic info from ____ to ____ or from one organism to its offspring
Cell to cell
What happens when a mistake is made?:
- DNA sequence changes may lead to changes in
____
– ____ appearance is a product of proteins produced
– DNA sequence changes may cause changes in
outward appearance
Protein, Outward
At individual level, changes in DNA sequence
might increase or decrease _____
– Change in finch beak size and shape
– Change in length of giraffe’s neck
Fitness
The ______ reactions that sustain the diversity
of life take pace inside cells and requires energy.
Chemical
Organisms 2 fundamental nutritional
needs:
- accquring chemical energy as adenosine triphosphate (ATP)
- Obtaining molecules that can be used as building
blocks to make DNA, RNA, proteins, etc.
How organisms acquire energy is central to the
diversification of life T or F
True
LECTURE 2 REVIEW
1.3 Life evolves
* The theory of evolution states that all organisms are related by
common ancestry.
* Natural selection is a well-tested explanation for why species
change through time and why they are so well adapted to their
habitats
LECTURE 2 REVIEW
1.4 Life processes information
* The chromosome theory of inheritance states that genes are
located on chromosomes.
* A chromosome consists of a molecule of DNA – the hereditary
material. Genes, located on chromosomes, consist of specific
segments of DNA that code for products in the cell.
* The flow of information from DNA to RNA to protein is called the
central dogma.
* Organisms are highly diverse in how they acquire and use
energy.
