More things to know

what is the scientific method?

systematic process for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge.

It involves making observations, forming hypotheses, conducting experiments, and analyzing results to draw conclusions.

origin of life

The origin of life refers to the process by which living organisms arose on Earth from non-living matter, particularly involving chemical reactions and environmental conditions that led to the formation of simple organic compounds, eventually evolving into more complex forms.

evolution of eukaryotes

the process by which complex cells with membrane-bound organelles, including a nucleus, arose from simpler prokaryotic organisms. This transition is believed to have occurred through a series of symbiotic relationships and endosymbiotic events, leading to the diversification of life forms.

evolution of multicellularity

the process by which single-celled organisms transitioned to form complex, multicellular organisms. This evolution allowed for specialization of cells and increased organismal complexity, enhancing survival and adaptation.

what are key evolutionary processes

natural selection, genetic drift, mutation, and gene flow. These mechanisms drive the adaptation and diversification of species over time.

natural selection

the process by which organisms better adapted to their environment tend to survive and produce more offspring. This mechanism plays a fundamental role in the evolution of species.

genetic drift

the random fluctuation of allele frequencies in a population, which can lead to significant changes over time, especially in small populations. This process can affect genetic variation and evolution.

gene flow

the transfer of genetic material between populations through migration or interbreeding, which can introduce new alleles and increase genetic diversity.

mutation

a change in the DNA sequence of an organism's genome, which can lead to new traits and contribute to genetic diversity. Mutations can be caused by various factors, including environmental influences or errors during DNA replication.

how can you identify evolving populations

Evolving populations can be identified by observing changes in allele frequencies over generations, presence of mutations, or increased genetic diversity through gene flow, indicating adaptation or evolution in response to environmental pressures.

how are species formed

Species are formed through processes such as speciation, where populations become reproductively isolated and diverge genetically over time, often resulting from factors like geographic separation, environmental changes, or genetic drift.

how are species defined

groups of organisms that can interbreed and produce fertile offspring, sharing common characteristics and genetic makeup. This definition emphasizes reproductive isolation from other such groups.

what favors adaptive radiation

factors such as ecological opportunities, diverse environments, and reduced competition, allowing species to exploit different niches rapidly.

what key innovations allowed invasion of land by plants and animals?

Key innovations include the development of structures for support, reproduction, and water retention, such as vascular tissues, seeds, and protective outer layers, enabling successful colonization of terrestrial environments.

how have phototrophs evolved from cyanobacteria to algae to non-vascular plants to vascular plants to seed plants?

Cyanobacteria

→ oxygenic photosynthesis evolves; ancestral photosystems form

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Primary endosymbiosis

→ chloroplasts arise

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Green algae (especially charophytes)

→ multicellularity, cellulose walls, chlorophyll a/b

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Non‑vascular plants (bryophytes)

→ land colonization, cuticle, protected embryos

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Vascular plants

→ lignin, xylem/phloem, tall sporophytes

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Seed plants

→ seeds, pollen, heterospory, extreme gametophyte reduction

mitotic vs meiotic division

Mitotic division results in two genetically identical daughter cells, while meiotic division produces four genetically diverse gametes through two rounds of division and crossing over.

alternation of generation

reproductive cycle in which an organism alternates between a haploid gametophyte stage and a diploid sporophyte stage, allowing for both sexual and asexual reproduction.

hardyweinberg equation

p² + 2pq + q² = 1

facultative vs obligate

Describes different survival strategies of organisms; facultative organisms can adapt to varying conditions while obligate organisms require specific conditions to survive.

fragmentation

A form of asexual reproduction in which an organism breaks into fragments, each capable of growing independently into a new organism.