HL Bio idk like nature test
Evolution
cumulative change in heritable characteristics of a population
Lamarck
Species change as a result of the habitual use or disuse of a feature. Like giraffes kept stretching their necks to reach leaves.
Darwin
Evolution by decent with modification or natural selection
Evidence for evolution
Base sequence changes of DNA and RNA and also amino acid sequence changes of proteins made using those base sequences. The closer in morphology two species are, the less differences in base sequences.
Hox gene family example
occurs widely in animal genomes. genes in this family help to determine the body plan during development. Occurs in all animals with a clear head-to-tail acis. these species form a clade called bilateria.
Domestic breeding
shows great variation compared to wild populations subject to only natural variation.
Selective Breeding
aka artificial selection. Breeding members of a species with a desired trait make the trait's frequency more common in successive generations. Provides evidence of evolution. Can cause rapid evolution. Natural selection was the OG for variation.
Homologous structures
forelimbs are different looking of different species but inside them the bones were relatively the same (positions). Pentadactyl limbs (five digit). homologous structures are those that are similar in shape in different types of organisms with different functions. inherited from common ancestry but evolved in diverse ways (adapted to different niches). Also, vesitigal organs (teeth in embryo of whales but when adults they have none, appendix in human, etc).
Analogous structures
similarities in function but when studied are very different. example is birds of wings and insects. had different origins but adapted to perform similar functions. convergent evolution.
Speciation by divergence of isolated populations
the biological defintion of species is based on the idea that they can produce fertile offspring. if two populations of a species become separated so they cannot interbreed, they can evolve in different ways. ex. fruit flies being on different islands and getting different mating rituals and genetic differences.
Extinction
when the last individuals of a species die out
Speciation
due to reproductive isolation and differential selection. before they can split into two species, they must stop interbreeding. it causes a missing of genes and a blending of traits. where there are significant differences in selection, its called divergent evolution.
Habitat
place where organisms live
species
a group of organisms that can interbreed to produce fertile offspring
population
a group of organisms of the same species that are living in the same area at the same time
community
a group of populations that are living and interacting together in the same area
ecosystem
a community and its abiotic environment
adaptations
processes that develop gradually through natural selection that help an organism survive and reproduce in a particular environment;
- Structural: physical differences
- Behavioural: differences in patterns of activity
- Physiological: variations in detection and response by vital organs
- Biochemical: differences in the molecular composition of cells and enzyme functions
- Developmental: variable changes that occur across the life span of an organism
ex. adaptation: Sand dune grass species (sea oats)
large shallow root system to maximize water uptake, narrow leaves that reduce transpiration, close their stoma if surrounding sand/soil is too dry
ex. mangrove tree species
roots extend above waterline for absorption of air for roots below water, tangles root system provides support and a protective aquatic habitat
abiotic factors (non-living components) examples
water, temperature, light, pH, soil, salinity
limiting factors
places an upper limit on the size of the population. can be biotic or abiotic.
conditions for coral reef formation
reef building coral forms a symbiotic relationship with algae, the coral provides the algae with a protective environment and source of inorganic compounds, the algae provides the coral polyps with a necessary source of nutrition
Biomes
named after dominant vegetation found there. factors affecting distribution; temperature and rainfall
convergent evolution
the independent evolution of similar features in species with distinct lineages. may occur when different species occupy same habitat and are subjected to the same selection pressures.
ex. wings in birds, insects, and bats
adaptive radiation
rapid evolution diversification of a single ancestral line. when same species occupy various niches. members evolve different morphological features in response (adaptations).
ex. type of breaks in finches
hot desert adaptations examples
saguaro cactus: waterproof
fennec fox: vascular ears to dissipate heat and have good kidneys for water absorption and also nocturnal.
tropical rainforest adaptation ex.
kapok tree: accessing more sunlight by strong above-ground roots and grow tall with shallow soil
poison dart frog: highly toxic skin, bright colours to warn predators, and lay eggs in areas with a lot of predators.
organism
an individual plant, animal, bacterium, or any other living thing
evolution by decent with modification or natural selection
charles darwin. species living today changed overtime and stemmed from one or a few ancestral organisms. limiting factors restrict this growth and those who have traits better suited to conditions would get an adaptation and reproduce. the ones most responsive to change survive (survival of the fittest)
variation between organisms
lots of variety today. There is less variation among members of the same species, but there is still some. Least variation is when two individuals are genetically identical (monozygotic twins), variation is essential for future life because natural selection would not happen without it. of source of variation is mutation altering DNA in a gamete. the more variation there is, the more resistant it is to diseases and changes in the environment
genetic drift
change in the composition of a gene pool as a result of a random or chance event
monozygotic twins
formed when a zygote or early-stage embryo divides and develops into two individuals. Monozygotic twins start out with the same genes but acquire differences through mutations and environmental factors
inherited variation
genetic variation within a population which can be inherited
competition
struggle for survival (species tend to produce more offspring than the environment can support)
species
a group of organisms with shared traits, at the time biologists described outer form and inner structure to classify species (morphology). This idea is the morphological concept of a species
selection
environmental pressures lead to differential reproduction within a population
evolution
over time there is a change in the allele frequency within the population gene pool
taxonomy
the branch of biology that identifies, names, and classifies species.
binomial nomenclature
refers to a two part naming system. An organism's scientific name has two parts, called the species/scientific name. The genus name begins with a capital letter and the species name with a small letter. both are always in italics or underlined, first letter can be written with just an initial. ex. Homo sapiens
selective pressures
external agents that affect an organism's ability to survive in a given environment. ex. resource availability, abiotic conditions, biological factors.
morphological species concept
a species is an unchanging group of organisms with clear differences in external form and internal structure between it and other species however this does not fit with the concept of evolution by natural selection proposed by charles darwin.
selective pressures: density-independent factors
abiotic event that affects population growth regardless of population density. ex. magellamic penguins in south America and the babies have fluffy ear to keep them warm, nit when it rains the feathers stick to the chicks and cause them to lose internal temperature.
Biological species concept
defines a species as a group of organisms that can successfully interbreed and produce fertile offspring. The concept explains how a group of individuals can exist as a coherent unit - the members of a species interbreed and therefore share genes in a gene pool. according to this, hybridization means that those two species are not distinct.
selective pressures: density-dependent factors
biotic interaction that varies in its effect on population growth.
interspecific competition
offspring/individuals/population compete for limited resources. this is one of the driving factors of evolutionary change. population produces more offspring that the carrying capacity of the environment.
fitness
contribution that an individual makes to the next generation by producing offspring that will survive long enough to reproduce
allele frequency
variation that exists within a population is heritable and determined by the presence of alleles. these alleles may be passed down. either beneficial, detrimental, or neutral. as beneficial alleles improve reproductive potential, they are more likely to be passed down. environmental conditions changes what constitutes an allele has beneficial or not.
Sexual Selection
sexual dimorphism has evolved as a result of differential mate selection of a species. females have cryptic colouring and males have exaggerated traits/colours/ornaments. ex. birds, deer, even humans
John Endler's great guppy experiment
does predation and gravel size affect the colouration of male guppies? yeah, when there is a predator, the number of spots decreases to become more camouflaged and also matched the size of spots to the gravel. without predators, they did wtv tf they wanted (opposite).
diversity in chromosome numbers of plant and animal species
chromosome number can change during evolution but it is very rare. most plants and animals have an even number of chromosomes (cause the haploid count doubles during the fusion of gametes).
Karyotyping/Karyograms
stained, burst, photographed, arranged in picture from longest pair to shortest. Each chromosome is visible during metaphase
Unity/Diversity of genomes
a genome contains genes. diversity in the genome of different species is mostly caused by variation. positions in a gene where more than one base may be present are SNPs. in one individual there is 4k-5k SNPs, so only 1 base in every 650k is different from the common one. sounds like low diversity but it is the main factor in making humans look different
genome size
measured in base pairs. large genomes can contain a lot of non-functional DNA
whole genome sequencing
it is determining the entire base sequence of an organism's DNA. over less than 10 years, the size of genomes being sequenced increased by a factor of 1000! the cost of this has dropped to less than 1k in 2020. principal goal of sequencing the genomes in a wide range of species is investigation of evolutionary origins, which will help prevent infectious diseases (in bacteria and viruses).
ecosystem diversity
the variety of ecosystems in a biosphere (ex. great barrier reef)
species diversity
variety of organisms present in an ecosystem. based off of richness of species and evenness of organisms. greater biodiversity = greater resilience against outside disturbances. (ex. if a top predator disappears due to hunting, there will be a crazy shift in community composition in a less biodiverse ecosystem than a more biodiverse one)
genetic diversity
variety of genes in a population of interbreeding individuals. gene pool is the sum of all the alleles (within a population). genetic diversity within a species is usually greater than that within a population.
historical comparisons of biodiversity
biodiversity tends to increase after mass extinctions.
classifying organisms on taxa
similar common DNA sequences are considered more reliable than physical characteristics.
1. lumpers believe that similarities are more important criteria than differences
2. splitter believe the opposite of lumpers
Anthropogenic factors that lead to extinction
habitat destruction, overfishing/hunting, invasive species, pollution, climate change.
ex. sea mink got extinct cuz of overhunting for fur trade.
ex. monk seal got extinct cuz of oil, food, and scientific specimens
ex. north sea giant moa got extinct cuz of hunting (1300 C.E.)
anthropogenic causes of ecosystem loss
agriculture, urbanization, overexploitation, mining, building dams, drainage of water, temperature.
ex. southeast asian forests: agricultural use
ex. sudbury forests: nickel mining/smelting
things to motor for biodiversity crisis
population size of species, range of a species, diversity, richness/evenness, area occupied, number of threatened species, genetic diversity
biodiversity crisis
unprecedented loss of ecosystems and species. IPBES assesses state of biodiversity and periodically produces reports that provide guidance for policymakers. data is sampled regularly to identify trends.
ICNU red list
each species assessed is rated on a scale indicated its ecological health. each entry contains the details of the research papers used (it is very reliable).
Simpson's reciprocal index
used to calculate biodiversity. the greater the biodiversity, the higher the values of D. the lowest possible defined value of D is 1 (only one species found).
D = N(N-1) / sum n(n-1)
where N is the total of organisms of all species and n is the number of organisms of a single species.
measuring population size
N = B-D
where N is change in population size, B is births, and D is deathers. the annual growth rate peaked in 60s for humans and has been declining ever since, but so is the death rate. population grows.
link between humans and biodiversity crisis
as population increases, more resources are required as well as more waste and pollution is produced. therefore, resources like food, water, and minerals must be sourced from ecosystems, causing damage and loss of biodiversity.
In-situ (strategy for the conservation of endangered species)
managing species in its natural habitat. meaning....
habitat, normal behaviours, an food web are maintained. captive breeding does not work for all species. habitat can be used for the reintroduction of animals from captive breeding programs. habitat remains available to other endangered species.
Ex-situ (strategy for the conservation of endangered species)
managing species away from its natural habitat. will work if habitat is lost, easy to isolate the animal from the threats, species maybe too rare to breed/maintain populations in the wild. captive breeding can quickly increase numbers for some species. .habitat can be used for the reintroduction of animals from captive breeding programs. habitat remains available to other endangered species.
in-situ: national parks and nature reserves
human visitors are allowed but no building on it. control of invasive species and human exploitation, opportunities for research, etc.
ex. banff national park
active management
where humans intervene in the conservation of an area. usually we need to take active steps in management of the area (to reverse damage caused by humans/invasive species/natural events). ex. elimination of alien/damaged species, fire-cleaning to kill invasive species, re-plant/re-introducing endangered species, etc.
ex-situ: efforts
breeding programmed by zoos
botanic gardens: living space for plants and biodiversity
seed banks: place where you can store living seeds
animal tissue bank: germplasm (sperm, egg, embryos used for captive breeding programs) and somatic tissue (non-reproductive tissue samples used for DNA research/cloning)
EDGE program
global program with the goal of selecting evolutionary distinct and globally endangered species. then selected primary status in conservation programs.
1. red list rating
2. species is evaluated for unique evolutionary history (DNA sequencing)
3. species that are most endangered and distinct are given a high EDGE score indicating they should be prioritized
ex. pygmy three-toes sloth
most abundant
thickest line
clade
a group of organisms that derived form a common ancestor