ch 22-25 bio

redoing it bc the ai sucks

Evolution

Change overtime in the genetic composition of a population

Aristotle classification

Species are fixed, arranged them on a scala naturae (ex. a latter with humans at the top and insects at the bottom)

The old testament classification

Species were individually designed by god

Carolus Linnaeus classification

Organismal adaptation; creator had designed each species for a specific purpose

Founder of taxonomy

branch of biology that classifies organisms

Carolus Linnaeus

Founder of taxonomy; binomial nomenclature

Levels of biological classification

Domain Kingdom Phylum Class Order Family Genus Species

Types of Domains

Eubacteria, Archaea, Eukarya

Georges Cuvier

Developed paleontology-study of fossils

Catastrophism

Each boundary between strata represents a catastrophe

Gradualism

Geologic change results from slow & gradual, continuous process

Uniformitarianism

Earth’s processes same rate in past & present (therefore Earth is very old)

Jean-Baptiste Landmark

Published Theory of Evolution (1809)

Inheritance of acquired characteristics

Modifications can be passed on

Thomas Malthus

Believed that consequences of overproducing within environment= war, famine, disease (limits of human pop.)

Charles Darwin

An English naturalist who was well known for his theory of evolution through natural selection

Alfred Russel Wallace

Also an english naturalist who independently covered the theory of evolution through natural selection

Darwinian View

History of life is like a tree with branches that represents life’s unity & diversity

Natural selection

Nature decides winners vs. losers

Artificial selection

Human modification of other species by selective breeding

Adaptations

Enhances an organisms ability to survive and reproduce

Fossil record

Provides evidence of the extinction of species, the origin of new groups, and changes within groups overtime

Homology

Similarity resulting from common ancestry

Homologous structures

Anatomical resemblances that represent variations of a structural theme

Vestigal structures

Remnants of features that served important functions in the organisms ancestors (ex.appendix)

Molecular homogies

Genes shared among organisms inherited from a common ancestor

Convergent evolution

The evolution of similar, or analogous features in distantly related groups

Analogous traits

Arise when groups independently adapt to similar environments in similar ways

Pangea

supercontinent that used to exist but split apart due to continental drift

Speciation

The process where one species splits into two species

Microevolution

Changes within a single gene pool

Macroevolution

Evolutionary change above the species level

Biological species concept

Defined by Ernst Mayr, population whose members can interbreed & produce viable, fertile, offspring; reproductively compatible

Distinct species

Songs & behaviors are different enough to prevent interbreeding

reproductive isolation

barriers that prevent members of 2 species from producing viable fertile hybrids

Prezygotic barriers

A reproductive barrier that prevents mating or fertilization (if mating occurs)

Geographical isolation

species occur in different areas; physical barrier

Ecological isolation

Species occur in same region, but occupy different habitats so they rarely encounter each other

Temporal isolation

species that breed during different times of day, different seasons, or different years

Behavioral isolation

Unique behavioral patterns & rituals isolate species

Mechanical isolation

morphological differences can prevent sucessful mating

Gametic isolation

Sperm of one species may not be able to fertilize eggs of another species

Biochemcial barrier

Sperm cannot penetrate egg

Receptor recognition

lock & key between egg & sperm

Chemical incompatibility

Sperm cannot survive in female reproductive tract

Postzygotic barriers

prevent hybrid zyogte from developing into viable adult

reduced hybrid viability

genes of different parent species may interact and impair the hybrids development

Reduced hybrid fertility

Even if hybrids are “vigorous”, they may be sterile

Hybrid breakdown

Hybrids may be fertile & viable in first generation, but when they mate offspring are feeble or sterile

The biological species concept cannot be applied to:

fossils & asexual organisms (including prokaryotes)

Allopatric speciation

Geographically isolated populations

Sympatric Speciation

Overlapping populations; reproductive isolation

Autopolyploid

Extra sets of chromosomes

Adaptive radiation

Many new species arise from a single common ancestor

Hybrid zones

Incomplete reproductive barriers

Reinforcement

strengthening of reproductive barriers

Fusion

Weakening of reproductive barriers

Discrete characters

Can be classified on an either or basis

Point mutations

Changes in one base

Chromosomal mutations

delete, duplicate, disrupt, rearrange; usually harmful

Sexual recombination

contributes to most of genetic variation in a population

Population genetics

Study of how populations change genetically overtime

Population

Group of individuals that live in the same area and interbreed, producing fertile offspring

Gene pool

All of the alleles for all genes in all the members of the population

Fixed allele

All members of a population only have 1 allele for a particular trait

Hardy Weinberg Principle

The allele and genotype frequencies of a population will remain constant from generation to generation UNLESS they are acted upon by forces other than Mendelian segregation and recombination of alleles

Equilibrium

Allele and genotype frequencies remain cosntant

Hardy Weinberg Principle equlibrium

p+q=1

p

frequency of dominant allele (A)

q

frequency of recessive allele (a)

Hardy Weinberg Principle equation

p²+2pq+q²=1

p²

AA (homozygous dominant)

q²

aa (homozygous recessive)

2pq

Aa (Heterozygous)

Minor causes of evolution

Mutations and Nonrandom mating

Major causes of evolution

Natural selection, genetic drift, gene flow

Natural selection

Individuals with variations better suited to environment pass more alleles to next generation

Genetic Drift

Small populations have greater chance of fluctuations in allele frequencies from one generation to another

Founder effect

A few individuals isolated from larger population; certain alleles under/over represented

Bottleneck effect

Sudden change in environment drastically reduces population size

Gene flow

Movement of fertile individuals between populations; gain/lose alleles; reduce genetic differences between populations

How does natural selection cause evolution?

Natural selection can alter the frequencies certain traits in a population in 3 ways

directional selection

phenotype of one extreme in a distribution is selected for

disruptive (diversifying) selection

Both extremes selected for

stabilizing selection

Middle phenotype is selected for

Sexual dimorphism

difference between 2 sexes (ex. size, color)

Intrasexual

selection within same sex (ex. males compete w other males for females)

Intersexual

mate choice (ex. females choose a colorful male)

Diploidy

hide recessive alleles that are less favorable

Heterozygote advantage

greater fitness than homozygotes

How old is Earth?

4.6 billion years old

When did the first life forms appear?

3.8 billion years ago

RNA World

The theory that the first genetic material was RNA

Sedimentary rock fossils

Layers called strata

Mineralized fossils

hard body structures

Organic fossils

rare in fossils but found in amber and frozen tar pits

Incomplete record fossils

many organisms not preserved, fossils destroyed, or not yet found

Relative dating

Uses order of rock strata to determine relative age of fossils