IB Bio HL Unit 2

Fossil Record

fossils are evidence of evolution

Radiometric Dating

measuring the decay of radioactive elements to calculate how long its been since a material formed

Law of Superposition

the deeper a fossil is the older it is

embryology

the study of the development of embryos from fertilization to birth, to identify how species are similar.

Selective Breeding

evolution by choice of humans

Homologous Structures

structures that have been inherited by a common ancestor, they have similar structures but not necessarily the same function

Divergent Evolution

organisms that share a recent common ancestor that develop different traits due to their enviornments

Analogous Structures

similar functions but not structurally related, don’t have common descent

Convergent Evolution

different species independently evolve similar traits due to similar enviornments

Vestigial Structures

body parts that have lost their original function through evolution and are remnants of of features that were once needed.

Molecular Sequencing

compare DNA

Lamarck’s theory of evolution

first to propose a mechanism of evolution, his discovery was wrong

Use & Disuse

parts that are used become larger and parts that aren’t deteriorate

Inheritance of Acquired characteristics

organisms pass traits they acquire through there lifetime to their offspring

Darwin’s Theory of Natural Selection

influenced by geological theories, Lamarck’s inheritance theory, and Selective breeding

Natural Selection

inherited variations exist in populations and organisms with successful variation will better survive, reproduce, and pass their variations to the next generation. (Testable explanation)

Evolution

change in heritable characteristics of a population over time

Mechanisms of evolution

how/why the change occurs

Adaptive radiation

organisms diversify from an ancestral species into a variety of forms when changes in the environment open new environmental niches

Darwin’s Finches

put finches from the same ancestor on islands and found the beak shape changed based on the food available at each environment.

Descent with Modification

when organisms reproduce sexually they can have variations from their parents, the descend from their parents with some modifications, variations can be created from random mutation or created during the reproduction process

Common Descent

all living things on earth are related they share the same ancestor, because of descent with modification biodiversity is possible.

Variation

organisms of the same species have different variations, some variations are not inherited, natural selection works on the variations that can be inherited,

Inherited Variation

found in the DNA of organisms, created by genetic mutations and through sexual reproduction, RANDOM, they are passed to new generations through reproduction.

Competition

more individuals are produced than the amount that can survive (overproduction), organisms compete for the limited resources available, direct competition there is a winner who will survive

Fitness

a measure of reproductive success, the ability to survive and reproduce, because of variation some organisms have traits that make them better at surviving, fitness depends on the environment: a trait that is beneficial in one habitat could be harmful in another

Adaptation

any variation that helps an organism survive, over time populations change so there is a higher percentage of organisms with favorable traits, (if the environment changes what is considered to be an adaptation can change)

Structural Adaptations

variations in the body of organisms

Mimicry

one species resembles another species

Camoflauge

species resembles their surroundings

Behavioral Adaptations

variations in the instincts of organisms

Physiological Adaptations

variations in the metabolic processes of an organism

Selective Pressures

“choose” what traits are beneficial for survival and what traits are detrimental for survival, determined by environment and tie directly to fitness

Sickle Cell Allele

abnormal/mutated allele of the hemoglobin gene

Directional Selection

one extreme is favored over the others

Stabilizing Selection

the middle is favored over both extremes

Disruptive Selection

both extremes are favored over the middle

John Endler’s Guppies

saw evolution in fewer than 15 generations, female guppies prefer mates with bright colors but brought colors are more likely to get eaten by a predator

Gene Flow

when organisms from one population move to a new area their genes flow into the gene pool of that population, can change the genetic frequencies of the population

Gene Pool

all of the genes within a population

Genetic Drift

change in gene frequencies due to random chance

Genetic Mutations

any change into he DNA sequence of an organism, random

Mechanisms of Evolution

gene flow, genetic mutation, natural selection, genetic drift

Random fertilization

the randomness of which sperm reaches the egg first produces an infinite number of combinations

Morphological concept of species

classification of organisms into species based on shared physical characteristics

Biological species concept

defines a species as a group of organisms successful in interbreeding, producing viable offspring, and are reproductively isolated from other groups

DNA Sequencing

a technique that looks at the sequencing of the bases within a DNA molecule

Genome

all of the genetic information in an organism

Single nucleotide polymorphisms

replacement of a single nucleotide with another, created genetic variation within a species

Genome size

amount of DNA in a haploid cell

Haploid

1 copy of each chromosome

Diploid

2 copies of each chromosome

Autosomes

contain genes that do not play a major role in sex determination

Homologous Chromosomes

chromosomes with the same gene sequence, loci, and size

Locus/loci

a gene’s location

23rd pair of chromosomes

sex chromosomes, that play a major role in sex determination

Taxonomy

scientific classification and naming of organisms

Binomal nomenclature

two part scientific name of a biological species

Taxon

taxonomic unit at any level of hierarchy

3-Domain system

based of rRNA sequences, bacteria, archaea, eukarya

autotroph

an organism that creates its on food using light or chemical energy

heterotroph

an organism that cannot create its own food, instead takes nutrition from other sources

Eubacteria

unicellular prokaryotes that contain cell walls made of peptidoglycan, reproduce asexually

E. coli

heterotrophic bacterium that lives symbiotically in our intestines

Archaebacteria

unicellular prokaryotes with cell walls that aren’t made of peptidoglycan, reproduce asexually

extremophiles

organisms that thrive in extreme enviornments

thermophiles

organisms that thrive in high temperatures

halophiles

organisms that thrive in high salinity

acidophiles

organisms that thrive in low pH or acid

methanogens

organisms that thrive with low oxygen

motility

is achieved if the cell has flagella

animalia

multicellualr eukaryotic organisms, lack cell walls

plantae

multicellualr eukaryotic photosynthetic organisms, cell walls made of cellulose

fungi

mostly multicellualr, but some unicellular, cell walls made of chitin, use external digestion

Protista

eukaryotes that don’t fall under the other 3 kingdoms, most are unicellular

Population

a group of organisms of the same species living in the same area at the same time

allopatric speciation

speciation that occurs in different locations

prezygotic barrier

obstacle to mating or fertilization if mating occurs

sympatric speciation

speciation that occurs in the same location

postzygotic barrier

prevent offspring from two different species from developing into viable fertil adults

geographic isolation

physical barrier prevents seperate populations from breeding

behavioral isolation

unique behavioral practices or courtship rituals isolate species

temporal isolation

species breed during different times of day, different seasons, or different years, isolating them from other species

ecological isolation

species could potentially interbreed but they occupy different habitats and rarely encounter eachother

mechanical isolation

morphological differences prevent successful mating

gradualism

a steady and gradual transformation, big changes from cumulative small changes

punctuated equillibrium

stable for long periods before undergoing rapid abrupt change