Bio Test Pt. 1

Natural selection

- the process whereby organisms better adapted to their environment tend to survive and produce more offspring. - The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution.

Survival of the fittest

- A phrase that originated from Darwinian evolutionary theory as a way of describing the mechanism of natural selection. - The biological concept of fitness is defined as reproductive success

Mutations and sexual reproduction produce...

- Genetic variation, making evolution possible - The origin of species

The most common misconception about evolution is that...

- Individual organisms evolve during their lifetime - The results of natural selection are only apparent and truly shown on a population over time with traits expressed or not expressed leading to reproductive success

Lactase Pt.1

- Individuals who were able to make the sugar lactose in the small intestine during a time of famine and starvation were able to better survive by the only food source, milk. - Those who could not digest the lactose, were already malnourished and in tern became more dehydrated which lead to their inevitable death

Changes in distribution of adaptations that have affected Behavioral traits in a population? 🡪 behavior

- The behavior of the population may be affected due to the physical changes of the population. - In the case of lactose, the physical changes will be for the body not to produce extreme cramps, and gastrointestinal distress due to the consumption of dairy product

Changes in distribution of adaptations that have affected Physiological traits in a population? 🡪 physiological

- The physiological changes would be for the body to continue to produce the lactase enzyme in the small intestine to allow adults to consume dairy products. - This will change the physiology of the body and how to reacts to dairy products

Gene pool

- The total collection of genes in a population at any one time ---Genes are two or more alleles in a gene pool

Populations are...

- The units of evolution - A group of individuals of the same species living in the same place at the same time - We measure the evolution as a change in the prevalence of certain heritable traits in a population over a span of generations ---Insects that become pesticide resistance - Some populations that are isolated far away may not be exchange traits ---Populations on different island

Mutation

- a change in the nucleotide sequence of DNA ---Mutation is the ultimate source of genetic variation ultimately resulting in evolution

Natural selection is...

- content selecting of favorable traits in a population - unfavorable genes will be removed from the gene pool - fittest (being able to reproduce and pass it onto the next generation) --- if slow tigers started getting eaten, their slow genes are going to be removed from the population --- fast tigers will survive they will pass their traits - Survival of the fittest has to do with the ability to survive and reproduce to the next generation

What can cause microevolution?

Genetic drift, gene flow, and mutation

Behavioral traits

affect the ways an organism responds to its environment

Lactase persistence

continuation of lactase production beyond early childhood that allows a person to digest milk and dairy products

Evolution four factors

. the potential for a species to increase in number, . the heritable genetic variation of individuals in a species due to mutation and sexual reproduction, . Successful individuals have survived because of variant traits they have inherited and will pass them on to their children . the proliferation of those organisms that are better able to survive and reproduce in the environment.

Homologies indicate...

patterns of descent that can be shown on an evolutionary tree

Anatomical traits

physical characteristics

Survival of the fittest is not defined by...

- "fittest" directed toward strong body power - It is directed toward the ability to adapt to your surroundings to create the most optimal survival techniques and expression of traits to ensure survival - Defined by how many offspring you are able to produce (reproductive success) - This also ties into reproduction of population and species - The individuals in a species who are able to adapt to their changing surroundings and reproduce are the apex of the population.

Evolutionary tree

- A phylogenetic tree is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. - All life on Earth is part of a single phylogenetic tree, indicating common ancestry - Evolutionary trees are hypotheses reflecting our current understanding of patterns of evolutionary descent

Artificial selection

- Selective breeding is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits by choosing which typically animal or plant males and females will sexually reproduce and have offspring together ---Humans have modified other species by selecting and breeding individuals that possess desired traits

Natural selection

- The differential survival and reproduction of individuals due to differences in phenotype. - It is a key mechanism of evolution, the change in the heritable trait is characteristic of a population over generations - Does not create new genes or phenotypes, and instead edits the traits that one has

Changes in distribution of adaptations that have affected Anatomical traits in a population? 🡪 anatomy

- The physical appearance of the species will be changed and affected by natural selection dur to survival of the fittest. - The physical appearance of the population will be dominated by the most advantages traits in the physical appearance of the population

At some point after *weaning*

- most humans around the world lose the ability to digest lactose Lactose = the main sugar found in milk. Weaning = the process of gradually introducing an infant human or another mammal to what will be its adult diet while withdrawing the supply of its mother's milk ---The process takes place only in mammals, as only mammals produce milk

Individuals that are lactose intolerant, or lactase non persistent...

- no longer produce the enzyme Lactase - Those who can digest lactose are lactose tolerant or lactase persistent, because expression of the lactase gene persists beyond childhood and continue to produce lactase

Lactose tolerance (or lactase persistence) is found in

- so-called pastoralist populations ---About 7,500 to 9,000 years ago, certain groups of people began domesticating cattle and drinking their milk ---In such cultures, the lactase-persistence trait increased in frequency over time

Genetic variation

- the difference in DNA among individuals or the differences between populations. - There are multiple sources of genetic variation, including mutation and genetic recombination. ---Phenotype = genotype and environmental influences

Lactose is broken down by...

- the enzyme lactase Lactase is produced by cells lining the small intestine

In people that are lactose intolerant...

- the lactase gene gets "turned off" sometime after breastfeeding stops - In people who are lactose tolerant the lactase gene is permanently "turned on." ---Scientists have discovered that the gene remains "on" due to mutations that are not in the lactase gene itself but in a control region near it

Sexual reproduction

- the production of new living organisms by combining genetic information from two individuals of different types (sexes). - In most higher organisms, one sex (male) produces a small motile gamete (sperm) which travels to fuse with a larger stationary gamete (egg) produced by the other (female). - In organisms that reproduce sexually, most of the genetic variation in a population results from the unique combination of alleles that each individual inherits

Extinction

- the termination of a kind of organism or of a group of kinds, usually a species. - The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point ---A frequent event in Earth's history resulting in the irrevocable loss of species

Why can't an individual evolve?

- they retain the same genes throughout their life. - When a population is evolving, the ratio of different genetic types is changing -- each individual organism within a population does not change. - a result of natural selection over successive generations - individuals are selected. Populations evolve.

He stated that...

... as the descendants of a remote ancestor spread into various habitats over millions and millions of years, they accumulated diverse modifications or adaptations that fit them to specific ways of life

Darwin's 4 conditions

1) Individuals within a population differ 2) Competition for limited resources 3) The differences are, at least in part, passed from parents to offspring 4) Some individuals are more successful at surviving and reproducing than others

Mutations What are they? What do they do to a population?

1. A random error in gene replication that leads to a change 2. Mutations can introduce new alleles into a population of organisms and increase the population's genetic variation.

How did Darwin frame his theory of evolution?

A sea voyage - Charles Darwin observed different species of birds, all with different beaks that were adapted for the food they were eating in their environment

Physiological traits

Affect the ability of an organism to function

Evolution

Changes in the genetic composition of a population through successive generations.

What is as determinable as throwing a dice?

The chances of the recombination of alleles, genes, and traits (Its the chance of luck to get what you what)

Natural selection is (pt.2)...

The only mechanism that consistently leads to adaptive evolution

Lactase Pt.5

This caused the already malnourished individuals to become further dehydrated and lead to their eventual death

Lactase Pt.4

Those individual who were poor and unable to find food, other than drink the milk for nourishment, who were already malnourished, would have extreme cramps and diarrhea

Lactase Pt.2

Those individuals who are able to evolve and adapt to continue to make the sugar lactose in the small intestine are able to survive and thrive more than those who are unable to evolve and continue to produce the sugar

Lactase Pt.3

When people were domesticating cows around 10,000 years ago, they were still unable to digest the milk as adults resulting in gastrointestinal distress

Natural selection - How does it cause an increase and decrease in heritable traits over time in population?

it makes it so the unfavorable traits are reproducing while the favorable traits are diminished

Natural selection - How does it affect populations?

it weeds out the unfavorable traits and makes the less favorable traits dominate

Natural selection - What does it do?

makes traits that were one considered less favorable now more favorable based on environmental factors changing to make the once favorable traits less favorable

Fossils

the imprints or remains of organisms that lived in the past - In the mid 1700's the study of fossils by French naturalist, Jean Baptiste Lamarck, suggested that the best explanation for the relationship of fossils to current organisms is that life evolves - At the age of 22 Darwin set sale on a 5 year voyage along the South African coast line, when he returned, he started writing a novel to explain his findings and better explain the fossils he found - Darwin called this evolutionary history of life "descent with modification"

Lactose intolerant

the inability to digest lactose, the sugar found in milk; most adult mammals (including humans) are lactose intolerant as adults

Natural selection - How does it affect reproductive success?

the less favorable traits are decreased from the reproductive population while the least favorable traits are reproduced

Darwin proposed natural selection as...

the mechanism of evolution

Natural selection - What is it?

the process of naturally selecting the more favorable phenotypes in a population to make for the best possible chance in survival, survival of the fittest

Microevolution

the relative frequencies of alleles in population change over a small number of generations, evolution is occurring on small scale