biology. unit.

carolus linnaeus

developed binomial nomenclature and organism classification

Georges Louis Leclerc de Buffon

species share ancestors instead of arising separately, speces change with new habitats because of organic particles, earth is older than 7000 years

thomas malthus

populations increase exponentially but food increases linearly, people will fight when food runs out

georges cuvier

developed paleontology, extinctin, and catastrophism

catastrophism

theory that states that natural disasters shaped Earth's landforms and caused extinction of some species, while others repopulate area

Jean-Baptiste Lamarck

line of descent between fossil and current species, organisms become more complex, and the inheritance of acquired characteristics

inheritance of acquired characteristics

Lamarckian belief that characteristics acquired during the lifetime of an organism can be passed on to offspring

charles lyell

rejected catastrophism; suggested uniformitarianism: slow changes over time

Uniformitarianism

A principle that geologic processes that occurred in the past can be explained by current geologic processes, and changes occur over long periods of time

charles darwin

Developed the theory of evolution by natural selection

theory of evolution by natural selection

states that organisms that are better suited for their environments will survive and reproduce compared to those that are poorly suited for their environments, and organisms will continue to adapt

alfred russell wallace

independently came to same conclusions as Darwin about evolution (natural selection)

evolution

exists from variation and selection pressure

biogeography

Study of past and present distribution of organisms

biogeography displays evolution since

- animals found on islands closely resemble animals on nearest continent
- fossils of same species can be found on coastlines of neighbouring continents
- remote oceanic islands populated by animals rrived by water/ air which then evolve

comparative anatomy

similarities and differences in the anatomy of different species that display inheritance from a common ancestor

homologous structures

similar structure, different function

analogous structure

similar function, different internal structure and development

vestigial structure

remnants of an organ or structure that functioned in an earlier ancestor

paleontology

rock layers with fossils create record of changes

fossils display evolution since

younger fossils are more similar to existing species than older ones

fossils may be incomplete since

- species with delicate bodies don't fossilize
- species don't live in conditions for fossilization
- fossils haven't been found yet

transitional fossils

Fossils that provide patterns of evolutionary change from the early ancestors to modern life forms.

comparative embryology

the study of the similarities and differences in the embryos of different species

embryos vestigial structures

have many vestigial structures which aren't present in adult

comparative biochemistry

DNA and proteins are similar in species that share a common ancestor

universal genetic code

codes proteins, closely related speces have more similar sequences

microevolution

small scale evolutionary change represented by a generation shift in a population's relative allelic frequencies

causes of microevolution

genetic drift, gene flow, mutations, nonrandom mating, natural selection

genetic drift

random change in allele frequencies that occurs in small populations

genetic drift includes

founders effect and bottleneck effect

bottleneck effect

Genetic drift resulting from the reduction of a population, typically by a natural disaster

founders effect

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

genetic drift causes genetic variability to

decrease

gene flow

movement of alleles from one population to another

gene flow causes genetic variability to

increase

mutation

change in gametes, sudden change in gene pool

mutation's effect is

minimal on large populations

mutation is important for evolution sincec

it creates genetic variation, the basis of natural selection

if mutations increase, it's due to

genetic drift or natural selection

nonrandom mating

Mating based on phenotype or inbreeding

natural selection

selective forces affect populations, allels selected for by environmental conditions will increase in frequency

types of natural selection

directional, stabilizing, disruptive, sexual

stabilizing selection

favours average, reduces variation

directional selection

favours one extreme and can lead to rapid evolution

disruptive selection

favours both extremes, leading to the evolution of two species

sexual selection

competition for mates drivs sexual selection

two types of sexual selection

intrasexual and intersexual

intrasexual selection

selection within the same sex, individuals of one sex compete directly for mates of the opposite sex

intersexual selection

individuals of one sex are choosy in selecting their mates from the other sex

gene pool

Combined genetic information of all the members of a particular population

allelic frequency

the percentage of any specific allele in the gene pool

fixed allele

all members of a population are homozygous for that allele

Hardy-Weinberg equilibrium

The condition describing a non-evolving population (one that is in genetic equilibrium).

Hardy-Weinberg Principle

allele frequencies in a population remain constant unless one or more factors cause those frequencies to change

hardy weinburg principle suggests

sexual reproduction alone doesn't change allele frequencies

5 factors that cause evolutionary change

natural selection, small population size, mutation, immigration/emigration, and non-random mating

hardy-weinberg formulas

p + q \= 1,
p^2 + 2pq + q^2 \= 1

niche

An organism's particular role in an ecosystem, or how it makes its living.

adaptive radiation

the fast diversification of an organism into different forms filling different ecological niches to have less competition

ecological role

producer, consumer, or decomposer

divergent evolution

the large-scale evolution of a group into many different forms

outcomes of divergent evolution

minimized competition and increased biodiversity

convergent evolution

evolution toward similar characteristics in unrelated species

outcomes of convergent evolution

evolution of similar traits in similar environments and analogous features

coevolution

Process by which two species evolve in response to changes in each other

coevolutionary arms race

a repeating cycle of reciprocal adaptation

outcomes of coevolution

species increasingly dependent on each other

speciation

Formation of new species, when members of a similar population are reproductively isolated

reproductive isolating mechanism

behavioural, structural, or biochemical trait preventing individuals from reproducing successfully together

prezygotic mechanisms

prevent mating or fertilization

postzygotic mechanisms

prevent the development of a zygote

prezygotic mechanisms include

ecological, temporal, behavioral, mechanical, gametic

ecological isolation

species occur in the same area but occupy different habitats

temporal isolation

two species breed at different times of day, seasons, or year.

behavioural isolation

Courtship and mating behaviours are different

mechancial isolation

sex organs do not fit

gametic isolation

When sperm can't fertilize the eggs.

postzygotic mechanisms include

zygotic mortality, hybrid inviability, and hybrid infertility

zygotic mortality

Egg is fertilized, but zygote does not develop.

hybrid inviability

fertilized egg dies before birth or cannot live long

hybrid infertility

viable hybrid offspring cannot reproduce

two types of speciation

allopatric and sympatric

allopatric speciation

two populations are geographically isolated prior to becoming separate species

sympatric speciation

populations remains in physical contact with each other but stop exchanging alleles, becoming separate species

gradualism

species originate through a gradual change of adaptations

punctuated equilibrium

speciation is rapid and followed by long periods of no change or genetic equilibrium

dna

deoxyribonucleic acid

dna is made out of

phosphate, deoxyribose sugar, nitrogenous bases

chromatin

dna wrapped around histome proteins

chromosome

chromatin coiled tightly

mitosis

asexual reproduction

parts of mitosis

interphase, prophase, metaphase, anaphase, telophase, cytokinesis

interphase

G1 (cell growth), S (DNA replication), G2 (prepare for mitosis)

prophase

- nuclear membrane dissolves
- dna winds into chromosome
- spindle fibres appear
- centrioles move to opposite sides

metaphase

sister chromatids line up in the middle of the cell

anaphase

Spindle fibers pull chromosomes apart

telophase

- unwind into chromatin
-spindle fibres dissappear
- cleavage furrow
- nuclear membrane reappears

meiosis

Cell division that creates haploid sex cells (gametes) from parent cells

fertilization

2 haploid cells join to form zygote