10TH GRADE BIOLOGY - EVOLUTION
limiting factor
Any factor (biotic or abiotic) that restricts the existence of organisms in a specific enviornment.
Bottleneck
Any kind of event that reduces the population significantly. (examples: earthquake, flood, disease...)
Sexual reproduction
results in variation of traits in offspring as a result of crossing over in meiosis and mutations
Evidence for Evolution
1. Common ancestry 2. Homologous structures 3. Embryo Development 4. Vestigial Organs 5. Fossils
Causes of mutations
1. DNA fails to copy accurately. 2. External influences (ex. exposure to chemicals)
Post Darwin Beliefs
1. Earth is billions of years old. 2. The planet has changed and organisims have changed as well (found through fossils)
Pre-Darwin Beliefs
1. Earth was only a few thousand years old. 2. Neither the planet nor species that inhabited earth had changed since the beginning of time
2 types of genetic drift
1. Founder effect 2. Population bottleneck
4 steps of natural selection
1. More offspring are produces than can survive 2. in any population individuals have variation 3. Advantageous variations survive and pass on their variations to the next generation 4. Over time, offspring with advantageous variations make up most of the population.
The range of effects of germ line mutations
1. No change occurs in phenotype 2. Small change occurs in phenotype 3. Big change occurs in phenotype
3 conditions for natural selection to occur
1. Variation must exist among individuals 2.Variation must result in differences in the number of offspring surviving 3. Variation must be genetically inherited.
Mutations
A change in DNA Example: antibiodic resistance in bacteria
Ecosystem
A community of organisms (biotic) and their nonliving (abiotic) environment
Species
A group of organisms so similar to each other that they can reproduce and have fertile offspring.
Habitat vs. Niche
A niche is determined by the limiting factor
A group of one species that interbreed and produce fertile offspring and compete with each other for resources is called
A population
mutation
A random change in the DNA of a gene.
Founder effect
A small population that branches off from a larger one. It may or may not be genetically representative of the larger population that it came from.
Genetic shuffling
A source of variation
Genetic Variation
Any change in gene (and allele) frequencies within a population or species is Evolution
Are mutations neutral, harmful or beneficial
All
population
All individuals of a species that live in an area.
Biosphere
All life on Earth and all parts of the Earth in which life exists, including land, water, and the atmosphere.
Allele
An alternative form of a gene (one member of a pair) located at a specific position on a specific chromosome
predator
An animal that hunts other animals (prey) for food
Producer (all autotrophs (plants))
An organism that can make its own food.
parasite
An organism that feeds on a living host (host)
prey
An organism that is killed and eaten by another organism
consumer (all heterotrophs)
An organism that obtains energy by feeding on other organisms
Heterotrophs
An organism that obtains organic food molecules by eating other organisms or their by-products.
Niche
An organism's particular role in a community; its total way of live
In order of natural selection to occur, there must be:
At least two varieties of a species must exist.
Green plants that synthesis sugars from CO2 and H20 are
Autotrophs
Jean-Baptiste Lamarck
Believed that: 1. all organisms can change their traits during their lifetime by use or disuse. 2. Traits are passed on to offspring and over time this would cause change in a species LAMARK WAS WRONG
The highest level of organization
Biosphere
Non-random mating
Can change allele frequencies because the choice of mates is often an important part of behaviour. Plants self-pollinating is a form of non-random mating (inbreeding).
meiosis
Cell division that produces reproductive cells in sexually reproducing organisms
Charles Darwin
Credited with the Theory of Evolution & Natural Selection. Voyage of the HMS Beagle
What can cause changes in all aspects of life?
DNA
A science of relationship
Ecology
Abiotic + biotic factors =
Ecosystem
Natural selection
Environmental conditions determine which individuals in a population produce the most offspring.
What did Darwin find on his voyage on HMS Beagle
Finches on each island in the Galapagos had different types of beaks. Tortoises on each island in the Galapagos had different types of shells
What are the only mutations that matter to large-scale evolution
Germ Line mutations
Homologous Structures
If animals evolved from a common ancestor, they should share common structures
The competitve EXCLUSION principle
If two species with the same niche (role), coexist (live) in the same ecosystem, then one will be excluded from the community due to intense competition.
Two types of sexual selection
IntRAsexual selection and intERsexual selection
Two types of sexual selection
Intrasexual selection intersexual selection
Amount of water Amount of food Temperature Amount of space Availability of mates are all examples of_______
Limiting factors
What causes a inheritable change in the genotype?
Mutation
sources of genetic variation
Mutation recombination
Variation can be acted upon by natural selection because of
Mutations
What is the only source of ADDITIONAL genetic material and new alleles
Mutations
What provides the raw material for natural selection to act
Mutations
Germ Line Mutations
Mutations that can be passed on to offspring. They occur in reproductive cells.
When nature "selects" which organisms will be successful
Natural selection
Mechanisms of Evolution
Natural selection Gene flow Genetic Drift Mutations Non-random mating
recombination
New allele combinations form in offspring.
Somatic Mutations
Occur in non-reproductive cells and won't be passed to offspring.
Sexual selection
Occurs when certain traits increase mating success
Darwin's hypothesis
Organisms had a common ancestor, but had adapted to their enviornments and changed over time. He published his research in 1859
autotrophs
Organisms that are able to make their own food.
habitat
Place where an organism lives
Three types of feeding relationships
Producer - consumer Predator - prey Parasite - host
Allele Frequency
Proportion of gene copies in a population of a given allele
homologous structure
Similar structures that related species have inherited from a common ancestor.
Vestigial Organs
Structures or organs that no longer have a useful function (in humans - tailbone and appendix)
3 things that measure how fit an organism is
Survival - how long does an organism life mating success - how often it mates Number of offspring per mating that survive
heritability
The ability of a trait to be passed down from one generation to the next.
genetic drift
The change in allele frequencies by chance. Directly related to the population numbers - smaller population sizes are more susceptible because there is a greater chance that a rare allele will be lost.
gene pool
The combined alleles of all of the individuals in a population.
Variation
The difference in the physical traits of an individual compared with others of the same group.
DNA
The hereditary material of life. It affects looks, behavior and physiology.
fitness
The measure of the ability to survive and produce more offspring. A phenotype with greater fitness usually increased in frequency - most fit is given a value of 1.
Gene Flow
The movement of alleles in or out of a population (immigration or emigration).
Evolution
The process of biological change where descendants come to differ from their ancestors. Individuals don't evolve, populations do.
Artificial selection
The process where humans change a species by breeding it for certain traits.
Ecology
The scientific study of interactions between organisms and their enviornments, focusing on energy transfer
biogeography
The study of the distribution of organisms around the world
Biodiversity
The total number of different species in an ecosystem and their relative abundance.
what is the overall effect of gene flow?
To counteract natural selection by creating less differences between populations
fossil
Traces of organisms that existed in the past. Scientist can trace how a species evolved by studying them.
Population Bottlenect
When a population undergoes an event causing a significant percentage of the population
Voyage of the HMS Beagle
a 5-year voyage to South America and South Pacific, collecting specimens, making observations and keeping a scientific journal of his findings
adaptation
a feature that allows an organism to survive better in its enviornment. Adaptations can lead to genetic change over time.
A mutation in the DNA of a gene can result in
a new allele.
biotic factors
all living organisms inhabiting the earth
organism
any unicellular or multicellular form exhibiting all of the characteristics of life, an individual.
Two factors that make up the enviornment
biotic factor abiotic factor
Intrasexual selection
competition among males
Community
different populations that live together in an area (enviornment) and are interdependant (depend on each other)
What can introduce new alleles into a gene pool or change allele frequencies
gene flow
Common Ancestroy
if a species evolved from a common ancestor, they should share common anatomical traits.
the type of mutation that cause the death of an organism is called
lethals
intersexual selection
males display certain traits to females (like a peacock displaying his feathers)
Most recombination occurs during
meiosis
abiotic factors
nonliving parts of the environment (examples: temperature, soil, light,moisture, air currents)
what is the lowest level of organization
organism
analogous structre
structures that don't have a common evolutionary origin but are similar in function
what happens if a mutation occurs in the reproductive cells
the mutation can be passed on to the offspring.
