BIO 1300- Chapter 1

UCCS biology 1300, for bio majors

Traits of living things

Traits of living things

made of cells, grow and develop, reproduce, use energy, stimulus (response to), made of DNA, predictable makeup

Order and complexity

something is repetitively predictable

response to environment

reaction to external stimulus

reproduction

the production of offspring

growth and development

change in individual's structure over a lifetime

energy transformation

the ability to capture energy and change it into a usable form

regulation

keep internal conditions stable relative to environment

evolutionary adaptation

a change that occurs at the genetic level over many generations

DNA

genetic molecule in all living cells

hypothesis

a tentative description of a pattern or explanation for an observation

Generalizing hypothesis

statement that describes an observed pattern in nature

explanatory hypothesis

statement that describes why an observation occurs

Scientific method

A logical, systematic approach to the solution of a scientific problem

Step one in the scientific method

observation and questioning

Step two in the scientific method

Form a hypothesis

Step three in the scientific method

Predict the consequences of the hypothesis

Step four in the scientific method

experiment

Step five in the scientific method

Analyze data and state results

Step six in the scientific method

Interpret a conclusion from the data

theory

well-tested explanation that unifies a broad range of observations

Evolution

a change in heritable traits of biological populations over generational time

trait

specific characteristic of an individual, can be physical or behavioral

Mechanisms of evolution

mutation, natural selection, genetic drift, gene flow, recombination

Mutation

random changes in DNA sequences

The founder affect

genetic drift that occurs after a small number of individuals colonize a new area

The bottleneck affect

A change in allele frequency following a dramatic reduction in the size of a population

Evidence for evolution

fossil records, comparative anatomy, molecular biology, biogeography, embryology

Fossil records

provide evidence of changes in population over time

Comparative anatomy

homologous structures indicate common ancestory

Molecular biology

DNA similarities indicate common ancestory

Biogeography

Geographic distribution of species.

Embryology

similarities in embryonic development indicate a common ancestor

cell theory

the cell is the basic unit of life, all living things are made of cells, all cells arise from existing cells

bacteria

unicellular, prokaryotic organisms

archaea

unicellular, prokaryotic organisms; most live in extreme environments

eukaryote

organisms who’s cells contain a membrane bound nucleus and internal compartments

protists

eukaryote; algae, slime, mold

fungi

eukaryote; molds, mushrooms

classification order

kingdom, phylum, class, order, family, genus, species (kids play croquet on front green space)

discovery science

“natural history,” scientists make observations about the natural world to try and describe patterns and relationships; hypothesis driven

independent variable

variable we are able to manipulate/change

dependent variable

variable we seek to measure, response to

confounding factor

a variable other than the one tested which explains the results

error

a variable not accounted for in the experiment which means the results are not accurate

allele

an alternate version of a gene

fitness

an organisms ability to survive and reproduce in a particular environment

natural selection

adaptations arise which allow certain organisms to survive and reproduce at a higher rate

types of natural selection

directional, disruptive, stabilizing, sexual

directional selection

one extreme phenotype is favored over other extreme and moderate phenotypes

directional selection graph

disruptive selection

extreme phenotypes are favored over more moderate phenotypes

disruptive selection graph

stabilizing selection

average, non extreme phenotype is favored over extreme phenotypes

stabilizing selection graph

sexual selection

individuals with certain inherited characteristics are more likely than others to obtain mates

intrasexual selection

competition between members of the same sex for access to mates

intersexual selection

one sex chooses a mate from the opposite sex with certain inherited characteristics

sexual dimorphism

differences between males and females in terms of size, color, ornamentation, behavior, etc.

genetic drift

random chance events that affect the genetic makeup of the existing population. especially significant in small populations, the founder or bottleneck effect

gene flow

genes or alleles enter or leave populations due to the movement of fertile individuals

recombination

swapping genes between chromosomes after duplication

Hardy-Weinberg Equation

calculates the genetic variation of a population at equilibrium, can only be applied to organisms who mate randomly; p2+2pq+q2=1

speciation

the process by which populations evolve to become distinct species

biological species concept

a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring

limits of the biological species concept

can’t apply to asexual reproducing organisms or extinct organisms only known through fossils

prezygotic

before fertilization

postzygotic

after fertilization

prezygotic reproductive isolation forms

habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, gametic isolation

postzygotic reproductive isolation forms

reduced hybrid viability, hybrid breakdown, reduced hybrid fertility

Allopatric speciation

Speciation that occurs in different geographic areas

Sympatric Speciation

speciation that occurs in the same geographic area

Adaptive radiation

the rapid evolution of a single ancestral species into a diverse array of new species, each adapted to exploit different ecological niches within their environment; occurs when new resources become available or environmental conditions change significantly

phylogeny

an evolutionary history of a species or group of organisms

phylogenic tree

a branching diagram that represents a hypothesis about the evolutionary history of a group of organisms

taxonomic units

kingdoms, phyla, species…

Basal taxon

the taxon that diverged the earliest from all others

sister taxa

groups of organisms that share an immediate common ancestor

branch points/nodes

where speciation events and divergence occurred, most recent common ancestor of subsequent events

habitat isolation

when two species that could interbreed, don’t, because they live in different geographic areas

temporal isolation

when species that could interbreed, don’t, because the different species breed at different times

behavioral isolation

species perform many different mating rituals that are ignored by species not able to recognize said ritual as mating behavior

mechanical isolation

when two organisms aren’t able to procreate with one another because their sexual reproductive anatomy isn’t compatible

gametic isolation

sexual reproductive cells (sperm/eggs) aren’t able to fertilize the cells of another species, only designed for the specific species

reduced hybrid viability

when two organisms from different populations produce first generation offspring with reduced fitness, marked by decreased rates of survival and reproduction; offspring not strong enough to reproduce

hybrid breakdown

when two species are able to mate and produce viable offspring in the first generation; however, with continuing generations, the subsequent offspring are less and less able to survive

reduced hybrid fertility

when two organisms are closely related but not compatible, reproduce; producing fit but sterile offspring