biology 102 exam

Influences on Darwin - Plato and Aristotle: Organisms can vary in complexity and can therefore be organized based on this complexity. Every species on earth has a perfect essential form and that species variation is imperfection of this form

Influences on Darwin - Georges-Louis Leclerc (GLL): Eighteenth Century naturalist chronicled all species of plants and animals alive at the time. Proposed that evolution, or variation in species, can occur as a result of environmental influence or the struggle for existence

Influences on Darwin - Carolus Linnaus:

- believed species have an ideal
- believed in the ladder of life(scala naturae), the least complex organisms occupy the lowest rung, upper rungs are occupied by humans angels and gods
- developed the binomial system of nomenclature
- father of modern taxonomy*

Influences on Darwin - Erasmus Darwin(grandpa): hypothesized lightly about evolution based on observations and surroundings
animal development, animal breeding practices by humans, presence of vestigial organs

Influences on Darwin - Baron Georges Cuvier

- founded the science of paleontology
focused on dating fossils based on their location in the layers of the earths strata
- Explained why fossils change in each layer by catastrophism

Influences on Darwin - Jean Baptiste Lamarck

- Biologist that developed the first testable hypothesis of evolution*
- Stated evolution was a result of inheritance of acquired characteristics*
- The environment can cause a phenotypic change over time*

Influences on Darwin - James Hutton

- Proposed a theory of slow, uniform geological change

Influences on Darwin - Charles Lyell

- Uniformitarianism-the natural processes that take place are the same now as they always have been

Influences on Darwin - Thomas Malthus

- Essay on the principle of population-the size of the human populations is limited only by the quantity of resources

Catastrophism: series of catastrophic events cause new species to move into area

Precambrian Era includes:

- first era
- 87% of geologic timescale
- very first cells*
- first cells were photosynthetic prokaryotes
- living stromalites contain cyanobacteria, little oxygen, formation of an ozone field
- Eukaryotic cells eventually arose, via endosymbiotic theory
- multicellularity arose*

Paleozoic Era: second era, lasted about 300 million years
three major mass extinctions*
complex animals with exoskeletons
Plants and animals from aquatic life start to inhabit the land
Invertebrates and vertebrates*

Mesozoic Era: third era
Consists of the Triassic Jurassic and Cretaceous periods*
evolution of seeded plants: Allowed for further movement from water habitats
Dinosaurs evolved and experienced a mass extinction*

Cenozoic Era: fourth era
Mammals diversified, more evolved, primates evolved and gave rise to early humans*
Many forms of megafauna: giant animals

homologous structures: similar physical features that share a common ancestor but the features serve completely different functions ->evidence of common ancestor***

Analogous structures: have a similar function but evolved separately-> not evidence of common ancestor***

Miller-Urey experiment: Two scientists attempted to reproduce the condition of the (assumed) earth's primitive ocean's under a reducing atmosphere. They produced some of the key molecules to life (amino acids and nucleotides).... recreated primordial soup conditions!

Darwin's Theory of Evolution: all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce.

Biological Fitness: a measure of the ability to survive and reproduce relative to other members of the population

Darwins 4 main principles:

1. Variations that can be passed from one generation to the next
2. compete for available resources
3. individuals differ in terms of reproductive success
4. adapt to changes as environment changes

Evolution Evidence - Anatomy: homologous structures which are similar in structure / different function, evidence of a common ancestor

Vestigial strictures: remnants of organs or structures that had a function in an early ancestor, but serve no purpose to the modern day species

Evolution evidence - Biochemistry: all living things contain DNA (same 4 nucleotides, different sequences) proteins (same 20 amino acids, different sequences)

Evolution Evidence - Embryology: similar embryos > different organisms
identical larvae > different adult body forms

Evolution Evidence - Fossils: can show the evolution of animals into different animals, for example a sperm whale has hip bones

Evolution Examples - Geography: different locations = different species
island species most clearly resemble the nearest mainland species
->populations can show variation from one island to another

Pre-Darwin Views: all aspects of nature were considered as fixed and change was inconceivable

artificial selection: selective breeding of plants and animals to promote the occurrence of desirable traits in offspring done by humans

Natural selection: A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.
REQUIRES:
- variation
- inheritance
- differential adaptiveness
- differential reproduction

genetic drift: A change in the allele frequency of a population as a result of chance events rather than natural selection.
->does not necessarily lead to adaptations to the environment

bottle neck effect: random event prevents majority of individuals from contributing to the next generation
->next generation is composed of a small subset of the gene pool

Founder effect: change in allele frequencies as a result of the migration of a small subgroup of a population

Non-random mating: mating between individuals of the same phenotype or by those who live nearby

Natural Selection: the process by which random evolutionary changes are selected for by nature in a consistent, orderly, non-random way.

directional selection: Form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve
darkening of peppered moths in a polluted forest

stabilizing selection: form of natural selection in which individuals near the center of a distribution curve have higher fitness than individuals at either end of the curve
example: human babies with low or high birth weights are less likely to survive than those of average weight

disruptive selection: favors individuals at both extremes of the phenotypic range
example: coloration differences due to habitat

Sexual Selection: A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates. men compete to inseminate as many females as possible, continuous production of sperm. females are very selective because choice of mate is very serious as they produce few eggs

Heterozygous Advantage: On occasion keeping a harmful allele can be advantageous if it aids in the prevention of another pathogen or parasite

heterozygous advantage example: African American population: ancestors of modern-day African Americans came from malaria-prone areas. Those who adopted one of the alleles for the disease became immune and passed on their genes to offspring

species: a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding.

diagnostic traits: organisms are defined by their distinct physical characteristics

monophyletic: A branch that contains all the descendants of a common ancestor is said to be monophyletic

speciation: the splitting of one species into two or more species or the transformation of one species into a new species over time

allopatric speciation: geographic barrier

sympatric speciation: Speciation without a divided population. (No geographic barrier)

Divergent Evolution: Type of speciation that occurs when a single ancestral species gives rise to a variety of new species as each adapts to a specific environment

Convergent Evolution: occurs when a biological trait evolves in two unrelated species as a result of exposure to similar environments

Hox genes: series of genes that controls the differentiation of cells and tissues in an embryo
Hox genes are very similar in different animal groups

H-W equilibrium: states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences.

Gene flow: exchange of genes between populations

Genetic Mutations: Changes in the genetic material of cells that passes from one generation to another.
some lead to survival improvement