Lectures 2-11 Flashcards
Define: phylogeny
The history of the evolution of a species or group
Define: Clade
A group consisting of an ancestor and all of its descendants.
Define:Cladistics
The study of resemblance among clades.
Define: Monophyletic
A taxon that includes the most recent common ancestor of a group of organisms and all of its descendents.
Define: Paraphyletic
A taxon that includes the most recent common ancestor , but not all of its descendants.
Define: Polyphyletic
A taxon that does not include the common ancestor of the members in the taxon
Define: Shared derived character
A character that two lineages have in common, that evolved in the ancestor of a group and is present in all of its descendants e.g. hair on mammals. A shared derived character is unique to a particular clade.
Define: Shared primitive character
A shared primitive character is found not only on the clade being analysed but also on older clades. A character which is not unique to members of that clade.
Define: Outgroup
A species, or group of species that is closely related to the species that we are studying, but known to be less closely related than any members of the study group are to each other.
Define: phylogram
A phenotypic tree that has branch spans proportional to the amount of character change.
Define: Homologies
Similarities due to shared ancestry. These are structures which are similar in organisms that have similar ancestry e.g. the forelimb in mammals.
Define: Analogy
Similarity due to convergent evolution. This comes about when organisms from different evolutionary lineages develop similar structures as a result of the selection pressures of the environment in which they are living. These are not due to shared ancestry e.g. bird wing vs bat wing
Define: Taxonomy
An ordered division of organisms into categories based on their similarities and differences
Info: Homologous genes
2 types of homologous genes, Paralogous and orthologous.
Define: Paralogous genes
Paralogous genes results from gene duplication and are found in more than one copy in the same genome
Define: orthologous genes
Homologous genes that are found in different gene pools because of speciation.
Define: Molecular clocks
Allow for the measurement of the time of evolutionary change. They are based on the observation that some regions of the genome evolve at constant rates. by looking gat the fossil record, your able to deduct when certain species diverged.
Define: Homeoplasties
A character shared by a set of species but which is not present in the common ancestor.
Define: Analogy
Similarity in function and superficial resemblance of structures that have different origins (This is due to convergent evolution)
Define: Evolution
The sequence of events involved in the evolutionary development of a species or taxonomic group of organisms
Define: Catastrophism- cuvier
The theory that the earth has been affected in the past by sudden, short-lived, violent events possibly worldwide in scope. Catastrophism was advocated by Cuvier, Cuvier did not support evolution.
Info: Aristotle
opposed any concept of evolution and viewed species as fixed and unchanging. He viewed species as being arranged on a ladder, with each level being a different species and having the most complex species at the top of the ladder. He believed in Scala nature (‘the great chain of being’ ) essentially he believed that God created each species perfect and therefore there was no need for them to adapt.
Define: Gradualism- hutton
Profound change is the cumulative product of slow but continuous process. e.g erosion due to the flow of a river which will gradually make the river wider.
Define: uniformitarianism
The assumption that the same natural laws and processes that operate in the universe now have always operated in the universe in the past and apply everywhere in the universe.
Info: Darwin
Was profoundly influenced by Hutton’s and Lyell’s observations. Darwin developed two main ideas: Descent with modification and natural selection. Darwin found evidence to support his theory. He believed that species evolved over time and that the earth was much older than previous researchers thought.
Info: Hutton
James hutton perceived that changes in earths surface can result from slow, continuous actions still operating today. Supported gradualism.
Info: Lyell
Charles Lyell used evidence from fossils and buttons theory of gradualism to argue for gradual evolution. He established the idea of uniformitarianism.
Define: Descent with modification
All organisms are related through decent from a common ancestor that lived in the remote past.
How did the theory of natural selection come about?
This theory came about due to 5 observations made by Darwin.
1) If all individuals in a population lived, then population size would increase exponentially
2) Populations tend to remain stable in size
3) Environmental sources are limited
4) Individuals within a population vary extensively in appearance.
5) Much of this variation is heritable
What are 3 important points that need to be remembered about evolution through natural selection?
1) Populations evolve, individuals do not. natural selection occurs through individuals, however changes are seen in offspring, the parent does not evolve.
2) Natural selection can only act on heritable traits.
3) environmental factors vary from place to place, and an adaptation that was selected for in one environment =, may be detrimental in others.
Define: parsimony
Looking at multiple phylogenetic trees and deciding which one fits best in the situation
Define: pseudogenes
Paralogous genes that have lost the function of coding for any functional gene product
Define: Neutral theory
If a population carries several different versions of a gene, odds are that each of those versions is equally good at performing its job—in other words, that variation is neutral: whether you carry gene version A or gene version B does not affect your fitness.
What is a theory?
A set of assumptions, propositions, or accepted facts that attempts to provide a plausible or rational explanation of cause-and-effect relationships among a group of observed phenomenon.
What are extant species?
An extant species is one that is currently existing (i.e. the opposite of extinct)
Define: Innate behaviour
A behaviour which an animal was born with. I.e. an inborn behaviour.
Define: Bottleneck effect
A population bottleneck is a sharp reduction in the size of a population due to environmental events (such as earthquakes, floods, fires, disease, or droughts) or human activities. Such events can reduce the variation in the gene pool of a population, due to the fact that the only alleles available to represent the population would be the ones which survived. Therefore a reduction of Genetic variation occurs.
Define: Founder effect
The founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population.
Define: Genetic drift
Random changes in the frequency of alleles in a gene pool, usually of small populations.
Define: evolution
The change in the gene pool of a population from generation to generation by such processes as mutation, natural selection, and genetic drift.
Define: Acoelomate
A solid-bodied animal lacking a cavity between the gut and outer body wall
Define:Adaptation
Inherited characteristic of an organism that enhances its survival and reproduction in a specific environment
Define: Adaptive evolution
Evolution which results in a better match between organisms and their environment
Define: Adaptive radiation
Period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities.
Define: Allopatric speciation
The formation of new species in populations that are geographically isolated from another.
Define: Allometric growth
the increase in size of different organs or parts of an organism at various rates.
Define: Altruism
Selflessness, behaviour which reduces an individuals fitness while increasing the fitness of another individual
Define: Amphipathic
Having both a hydrophilic and hydrophobic region.
Define: Analogy
Similarity between two species that is due to convergent evolution rather than to descent from a common ancestor with the same trait.
Define: Anaphase
The fourth stage of mitosis, in which the chromatids of each chromosome have separated and the daughter chromosomes ares moving to the poles of the cell.
Define: Antidiuretic hormone
A peptide hormone that promotes water retention by the kidneys
Define: Associative learning
The acquired ability to associate one environmental feature (e.g a colour) with another (e.g a danger)
Define: Behaviour
An action carried out by muscles or glands under control of the nervous system in response to a stimulus.
Define: Bicoid
A maternal gene that codes for a protein responsible for specifying the anterior end in fruit fly.
Define: Biological clock
An internal timekeeper that controls the organisms biological rhythms.
Define: Biomass
The total mass of organic matter comprising a group of organisms in a particular habitat.
Define: Blastocoel
The fluid-filled cavity that forms in the centre of the blastula
Define: Blastocyst
The blastula stage of mammalian embryonic development.
Define: Blastomere
An early embryonic cell arising during the cleavage stage of an early embryo
Define: Blastopore
In a gastrula, the opening of the archenteron that typically develops into the anus in deuterostomes and mouth in protostomes.
Define: Archenteron
The endoderm-lined cavity, formed during gastrulation, that develops into the digestive tract in an animal.
Define: Blastula
A hollow ball of cells that marks the end of the cleavage stage during early embryonic development in animals
Define: Cell cycle
An ordered sequence of events in the life of a cell, from its origin in the division of a parent cell until its own division into two.
Define: cell plate
A membrane-bounded, flattened sac located at the midline of a dividing plant cell, inside which the new cell wall forms during cytokinesis
Define: Coelom
A body cavity lined by tissue derived only from the mesoderm
Define: Coelomate
An animal that possesses a true coelom
Define: Commensalism
A symbiotic relationship in which one organism benefits and the other is neither helped nor harmed (+/ neutral)
Define: Communication
A process involving the transmission of/ reception of and response to signals
Define: Community
All the organisms that inhabit a particular area
Define: Community ecology
The study of how organisms within a community interact with each other and how these interactions between species affect community structure and organisation.
Define: Competitive exclusion
The concept that when populations of two similar species compete for the same limited resources, one population will use the resources more efficiently and have a reproductive advantage that will eventually lead to the elimination of the other population
Define: Competitive inhibitor
A substance that reduces the activity of an enzyme by entering the active site in the place of a substrate, whose structure it mimics.
Define: Deductive reasoning
A type of logic in which specific results are predicted from a general premise.
Define: Diploblastic
Having two germ layers
Define: Triploblastic
Having three germ layers
Define: Deuterostome development
A developmental mode distinguished by the development of the anus from the blastopore.
Define: Directional selection
Natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than other individuals- therefore the curve shifts to one direction as one phenotype is selected for more strongly than the other.
Define: Disruptive Selection
Natural selection in which individuals on both sides of the phenotypic range survive or reproduce more successfully than other individuals- The two extreme phenotypes are selected for.
Define: Stabilising selection
Natural selection in which the most common phenotype is selected for and the two extremes are not.
Define: Exaptation
The utilization of a structure or feature for a function other than that for which it was developed through natural selection.
Define: Endoderm
The innermost of the three primary germ layers in animal embryos. Gives rise to the liver, pancreas,lungs, and the lining of the digestive tract in species that have these functions.
Define: Ectoderm
The outermost of the three primary germ layers. Gives rise to the skin, nervous system, inner ear, and lens of the eye.
Define: Exponential population growth
growth of a population in an ideal, unlimited environment, represented by a J-shaped curve when population size is plotted over time.
Define: Fixed Action pattern (FAP) <— hehe
A sequence of unlearned acts that is essentially unchangeable and, once initiated, usually carried out till completion.
Define: Frequency-dependent selection
Selection in which the fitness of a phenotype depends on how common the phenotype is in a population.
Define: Game Theory
An approach to evaluating alternative strategies in situations where the outcome of a particular strategy depends on the strategies used by other individuals.
Define: Gastrula
An embryonic stage in animal development encompassing the formation of three-layers: Ectoderm, Endoderm and mesoderm.
Define: Gastrulation
In animal development, a series of cell and tissue movements in which the blastula-stage embryo foods inward, producing a three-layered embryo, the gastrula.
Define: Gene Pool
The aggregate of all copies of every type of allele at all loci in every individual in a population
Define: Genetic variation
Differences among individuals in the composition of their genes or other DNA segments
Define: Germ layer
One of the three main layers in a gastrula that will form the various tissues and organs of the animal body
Define: Hamilton’s rule
The principle that for natural selection to favour an altruistic act, the benefit to the recipient, devalued by the coefficient of relatedness, must exceed the cost to the altruist.
Define: Hardy-Weinberg equilibrium
The state of a population in which the frequency of alleles and genotypes remain constant from generation to generation, provided that only mendelian segregation and recombination of alleles are at work.
Define: Hermaphroditism
A condition in which an individual has both male and female gonads and functions as both a male and a female in sexual reproduction by producing both sperm and eggs
Define: Heterochrony
Evolutionary change in the timing or rate of an organisms development
Define: Heterozygote advantage
Greater reproductive success of heterozygous individuals compared with homozygotes; this tends to preserve variation in the gene pool
Define: Heterozygous
Having two different alleles for a given gene
Define: Homeobox
A 180-nucleotide sequence within homeotic genes and some other developmental genes that is widely conserved in animals. Related sequences occur in plants and yeast.
Define: Homeostasis
The steady-state physiological condition of the body
Define: Homeotic Genes (also known as Hox genes)
Any of the master regulatory genes genes that control placement and spacial organisation of body parts in animals, plants and fungi by controlling the developmental rates of groups of cells
Define: Homologous Chromosomes (homologs)
A pair of chromosomes of the same length. centromere position, and staining pattern that possess genes for the same characters at corresponding loci.
Define: Homoplasy
A similar (analogous) structure or molecular sequence that has evolved independently in two species
Define: Homozygous
Having two identical alleles for a given gene
Define: Homochromy
a form of camouflage or protective colouring in animals that makes an individual visually become part of the whole group or landscape
Define: Heterochromy
a genetic shift in timing of the development of a tissue or anatomical part, or in the onset of a physiological process, relative to an ancestor.
Define: Heterotroph
An organism that obtains organic food molecules by eating other organisms or substances derived from them.
Define: Imprinting
In animal behaviour, the formation at a specific stage in life of a long-lasting behavioural response to a specific individual or object.
Define: Inductive reasoning
A type of logic in which generalisations are based on a large number of specific observations
Define: Intermediate disturbance hypothesis
The concept that moderate levels of disturbance can foster greater species diversity than low or high levels of disturbances.
Define: Intersexual selection (mate choice)
A form of natural selection in which individuals of one sex are choosy in selecting their mates from the other sex.
Define: Intrasexual Selection
A form of natural selection in which there is direct competition among individuals of one sex for mates of the opposite sex.
Define: Interspecific competition
Competition between individuals of different species for the same resources.
Define: iteroparity
Reproduction in which adults produce offspring over many years- also called repeated reproduction
Define: Karyotype
A display of the chromosome pairs of a cell arranged by size and shape
Define: K strategy
Were a small number of offspring are produced and obtain good parental care. Therefore each offspring has a high change of survival. e.g. most mammals
Define: R strategy
Were a large number of offspring are produced with minimal parental care with the hope that some survive to adulthood. This strategy is usually used by organisms which live in unstable environments e.g. some fish
Define: Keystone species
A species that is not necessarily abundant in a community yet exhorts strong control on community structure by the nature of its ecological role or niche. e.g. sea otter.
Define: Kin selection
Natural selection that favours altruistic behaviour by enhancing the reproductive success of relatives.
Define: Logistic population growth
Population growth that levels off as population size approaches carrying capacity.
Define: Mate-choice copying
Behaviour in which individuals in a a population copy the mate choice of others, apparently as a result of social learning.
Define: Maximum likelyhood
As applied to DNA sequence data, a principle that states that when considering multiple phylogenetic hypotheses, one should take into account the hypothesis which reflects the most likely sequence of evolutionary events, given certain rules about how DNA changes over time.
Define: Maximum parsimony
A principle that states that when considering multiple explanations for an observation, one should first investigate the simplest explanation that is consistent with the facts.
Define: Meroblastic
A type of cleavage in which there is incomplete division of the yolk-rich egg, characteristic of avian development.
Define: Mesoderm
The middle primary germ layer in triploblastic animal embryos. Develops into the notochord, muscles, lining of the coelom, skeleton, gonads, kidneys, and most of the circulatory system.
Define: Monogamous
Referring to a type of relationship in which one male mates with just one female.
Define: Mullarian mimicry
Two unpalatable species that mimic each other
Define: Batesian mimicry
Where a harmless species mimics a poisonous
Define: Aposematic Coloration
Where a species will display the fact that it is poisonous using colours (e.g the poison arrow frog)
Define: Mutualism
A symbiotic relationship in which both participants benefit (+/+)
Define: Symbiosis
A close relationship between two or more species.
Define: Parasitism
On organsim, the parasite gets food from another, its host, which is harmed in the process e.g. fleas (+/-)
Define: 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.
Define: Orthologous genes
These are homologous genes that are found in different species because of speciation
Define: Paedomorphosis
The retention in an adult organism of the juvenile features of its evolutionary ancestors.
Define: Paralogous genes
Homologous genes that are found in the same genome due to duplication
Define: Parthenogenesis
A form of asexual reproduction in which females produce offspring from unfertilised eggs
Define: phenotype
The observable physical and physiological traits of an organism, which are determined by its genetic makeup.
Define: Polygamy
A type of relationship where an individual of one sex mates with several of the other- 2 types polyandry and polygyny
Define: Polyandry
A relationship in which one female mates with several males
Define: Polygyny
A relationship in which one male mates with many females
Define: Promiscuity
The association of many males and females all breeding which each other. - No strong pair bonds or lasting relationships.
Define: Pseudocoelom
the body cavity of certain invertebrate animals between the body wall and the intestine, which is not lined with a mesodermal epithelium.
Define: Problem solving
The cognitive activity of devising a method to proceed from one state to another in the face of real or apparent danger.
Define: Punctuated equilibria
In the fossil record, long periods of apparent stasis, in which a species undergoes little or no morphological change, interrupted by relatively brief periods of sudden change.
Define: Quantitive character
A heritable feature that varies continuously over a range rather than in an either or fashion
Define: Radial symmetry
Symmetry in which the body is shaped like a pie or barrel and can be divided into mirror-imaged halves by any plane through its central axis.
Define: Reciprocal altruism
Altruistic behaviour between unrelated individuals, whereby the altruistic individual benefits in the future when the beneficiary reciprocates.
Define: Relative abundance
The proportional abundance of different species in a community
Define: Relative fitness
The contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals in the population.
Define: Resource partitioning
The division of environmental resources by coexisting species such that the niche of each species differs by one or more significant factors from the niches of all coexisting species.
Define: Semelparity (Big-Bang reproduction)
Reproduction in which an organism produces all of its offspring in a single event
Define: Sexual selection
A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.
Define: Sign stimulus
An external sensory cue that triggers a fixed action pattern by an animal.
Define: Signal
In animal behaviour, transmission of a stimulus from one animal to another.
Define: spacial learning
The establishment of a memory the reflects the environment’s spacial structure
Define: Species diversity
The number and relative abundance of species in a biological community
Define: Species richness
The number of species in a biological community
Define: Vestigial structure
A feature of an organism that is a historical remnant of a structure that served a function in the organisms ancestors.
Define: Agnostic behaviour
Any behaviour which frightens or damages a member of the same species
Define: Cognition
The mental process of knowing, thinking, learning and judging.
Define: Proximate cause
A proximate cause is an event which is closest to, or immediately responsible for causing, some observed result
Define: Ultimate cause
usually thought of as the “real” reason something occurred.
Define: Classical Conditioning
A process of behavior modification in which an innate response to a potent biological stimulus becomes expressed in response to a previously neutral stimulus; this is achieved by repeated pairings of the neutral stimulus and the potent biological stimulus that elicits the desired response.
Define: Operant Conditioning
A method of learning that occurs through reinforcements and punishments for behavior. It encourages the subject to associate desirable or undesirable outcomes with certain behaviors.
Hardy-Weinberg Equation
P2 + 2PQ + Q2 = 1
P= Frequency of the dominant allele Q= Frequency of the recessive allele
Define: Differentiation
the process by which a cell changes from one cell type to another.
Define: Maternal effect gene
A gene from the mother’s genome in which its phenotype in the zygote is influenced from the mother’s genotype, not from the zygote’s.
