Biology I Exam I Review

Characteristics of Life

1. Contain genetic information

2. Composed of cells

3. Homeostasis

4. Reproduce

5. Process energy

6. Growth

7. Respond to environment

Earth formed ________ years ago

4.5 billion

Life (prokaryotes) appeared _______ years ago

3.8 billion

_______ years ago prokaryotes performed photosynthesis

2.5 billion

Eukaryotes appeared ________ billion years ago

1.5

The ozone formed _______ years ago

800 million

First land plant appeared ______ years ago

450 million

First land animal appeared ______

365 million

First dinosaur appeared _____ years ago

230 million

First mammal appeared _______ years ago

200 million

Homo Sapiens appeared _____ years ago

500 thousand

Internal Hierarchy of Life

atom, molecules, macromolecules, organelles cell, tissue, organ system, organism

External hierarchy of life

individual, population, community, ecosystem, biome, biosphere

DNA consist of _______

nucleotides

What is a gene?

a specific segment of DNA that contains information for making proteins

Scientific hypothesis must be ______________ and ____________

testable and have the potential to be rejected

Science is based on evidence that comes from ________ and ____________

reproducible and quantifiable observations

Scientific body of work about mechanisms that cause evolutionary change in populations

evolutionary theory

Hardy-Weinberg

Steps of Scientific Method

1. Make an observation

2. Ask a question

3. Formulate a hypothesis

4. Make predictions

5. Design and conduct an experiment

6. Analyze results

7. Repeat experiment

Who was the first person to describe the evolutionary theory with scientific study and observations

Charles Darwin

What did Darwin discovered about the birds on the Galapagos Islands?

Natural Selection- birds on each island adapted (changes in beaks) to survive in their environment over time

Differential Survival-Birds with best adaptive traits (beak) survived to reproduce

Individuals do not evolve, __________ do

Population

What is a population

group of individuals of same species that live and interbreed in a an area

Adaptation

favored trait that spreads through a population by natural selection

Mutation

Change in nucleotide sequence

Alleles

Different forms of a gene

Gene pool

Sum of all copies of alleles in a population

Allele frequency

Proportion of each allele in gene pool (p and q)

Genotype frequency

Proportion of each genotype among individual in the population (#ind/total)

Mechanism that produces change

Natural selection

What is descent with modification?

divergent species share a common ancestor

Gene flow

Change in allele frequency in a population

Cause of gene flow

emigration(leave) and immigration(enter) of individuals in a population

Genetic drift

Changes in allele frequency from one generation to the next due to random sampling

Bottleneck effect

Large reduction of size of population, reduces genetic variation

Founder effect

Genetic drift changes allele frequencies when a few individuals colonize a new area

Nonrandom mating

when individuals mate preferentially with other individuals of the same genotype (including themselves i.e. self-fertilization in plants).

Sexual Selection

When individuals choose their mate based on particular traits

Hardy-Weinberg Equilibrium

Predicts genotype frequencies from alleles frequencies in the absences of evolution-allele frequencies do not change across generations at equilibrium

Conditions of Hardy-Weinberg Equilibrium

No mutation, no gene flow, no selection, random mating, large population size

Populations in nature (always/never) meet the conditions of Hardy-Weinberg equilibrium

never

Stabilizing selection

Selection that favors average individuals

Directional selection

favors one extreme, shifting in one direction from the mean

Disruptive selection

favors extremes over the mean/average-vary in both directions from the mean

____________ selection reduces variation in population

Stabilizing

What type of selection is also referred to as “purifying selection” because it selects against deleterious mutation to typical gene sequence

stabilizing selection

Positive selection

directional selection that favors a particular variant

____________ selection increases variation in population

disruptive

Disruption in gene flow leads to _________

speciation

Reproductive isolation

two groups of organisms can no longer exchange genes

Species

groups of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups.

As species diverge genetically, _______________ increases

reproductive isolation

Allopatric speciation

population separated by physical barrier

Sympatric speciation

speciation without physical isolation

Sympatric speciation commonly occurs by _________

polyploidy

polyploidy

duplication of sets of chromosomes within individuals

Autoployploidy

chromosome duplication in a single species

Allopolyploidy

combining chromosome of two different species

Tetraploid

result of two diploid gametes combining (reduction to haploid gametes did not occur)

___________ can self-fertilize with another __________

tetraploid

Prezygotic barriers

barriers to gene exchange before fertilization (mating)

Postzygotic barriers

barriers to mating after fertilization (mating). Low hybrid zygote or hybrid adult viability or hybrid infertility

Mechanical Isolation

Type of prezygotic isolation; differences in the size and shape of reproductive organs prevent union of gametes of different species

Difference in flower color and shape influence which pollinators are attracted to the flowers. This is an examples of which type of prezygotic barrier?

mechanical isolation

Temporal Isolation

Type of prezygotic isolation; differences in mating season (time) prevent two species from mating

Behavioral isolation

Type of prezygotic isolation; individuals reject or fail to recognize individuals of other species as potential mating partners

Differences in mating call of frogs, leading to no mating between other species, is an example of what type of prezygotic isolation

behavioral isolation

Habitat isolation

Type of prezygotic isolation; when two closely related species evolve preferences for living or mating in different habitats

Two populations of flies in the same geographical area live in different habitats: one lives in the soil and the other on the surface of the water, but the two population do not mate. This is an example of what type of prezygotic barrier

habitat isolation

Gamete isolation

Type of prezygotic isolation; sperm of one species may not attach to the eggs of another species because the eggs do not releases the appropriate chemicals, or sperm cannot penetrate the egg because they are chemically incompatible

Types of postzygotic reproductive barriers

hybrid zygote abnormality, hybrid infertility, low hybrid viability

Hybrid zones

due to incomplete reproductive isolation, a zone where closely-related species can cross and create hybrids

Factors that influence speciation rates

ecological specialization (ex. diets)

types of pollination

sexual selection

population bottlenecks

environmental changes

By pollination, speciation rates are higher in _______-pollinated that wind pollinated plants

animal

Phylogeny

the evolutionary history of descendants and their common ancestor

Lineage

series of ancestors and descendant populations

Phylogenic tree: node

A split in the tree occurs when lineage divides into two descendant lineages

Phylogenic tree: Traits

Dot on branches symbolizes a new trait that arose in a lineage

Phylogenic tree: Root

The first line of the tree is represents the common ancestor

Taxon

group of species with a designated name (ex: mammals, vertebrates, humans)

Clade

taxon that consist of all evolutionary descendants of a common ancestor

How to identify clade

pick a point on the tree and traces all descendant lineages to tip of terminal branch

Tree of life

complete evolutionary history of life

In the tree of life, what is the outgroup? Bacteria, archaea or eukarya

bacteria

Ancestral traits

traits inherited from a common ancestor

Homologous

features shared by two or more species that descended from a common ancestor (anatomically the same but may have different function)

Derived trait

traits that differ from its ancestral form (appeared in most recent ancestor)

Synapomorphies

derived traits that are shared among a group and are viewed as evidence of common ancestry of the group

The vertebral column is considered a __________ of all vertebrates

synapomorphy

Why are tetraploid and diploids individuals reproductively isolated?

Their hybrid offspring are triploid. They are viable but infertile

Homoplasies

similar traits created by convergent evolution and/or evolutionary reversal

Evolutionary reversal

species revert to ancestral state

Convergent evolution

Two species that evolved independently developed similar traits

Birds and bats having similar arm bone structure is an example of ____________

homologous

Birds and bats having wings despite evolving independently is an example of ____________

homoplasies

How is a species named

Genus and species

Neumonic for heirachy of taximony

King Phillip Came Over For Grape Soda

Paraphyletic

a group that does not include all the descendants of the common ancestor

Polyphyletic

group does not include its common ancestor