Evolution and Speciation

• Evolution and speciation are key concepts, focusing on ecosystems, allocating 4 hours for standard and higher levels, and an additional hour for advanced study.

Evolution and Heritable Traits

• Evolution refers to changes in the heritable characteristics of a population, distinguishing Darwinian evolution from Lamarckism which includes acquired, non-genetic changes.
• The theory of evolution via natural selection is considered a pragmatic concept due to its broad explanatory power and evidentiary support, although it cannot be definitively proven.

Evidence of Evolution Over Time

• Strong evidence supports the idea that populations' characteristics change, and this is called evolution, which is central to understanding life's diversity.
• Evolution pertains to traits inherited from parents and is defined as a change in the heritable characteristics of a population.
• Natural selection is the well-understood mechanism of evolution, also known as Darwinism.
• The characteristics of individual organisms changing during their lifetimes don't count, such as asymmetric tree growth due to wind; these are acquired characteristics

Flaws of Lamarckism

• Before Darwin, the prevailing theory, Lamarckism, suggested evolution was based on inheriting acquired characteristics, which has been disproven.
• Acquired characteristics are not inherited and do not lead to evolution because there's no evidence for environment-induced changes to genes

Genetic Evidence of Evolution

• Genetic changes in populations over generations serve as key evidence for evolution supported by DNA, RNA, and proteins.

Using DNA and RNA

• DNA and RNA sequences are vital, offering insights into evolutionary lineages when compared across species.
• DNA has adenine (A), thymine (T), cytosine (C), and guanine (G) bases, while RNA uses uracil (U) instead of thymine, where crucial genetic information relies on base pairing.
• Shared ancestry can be seen through shared DNA sequences in living entities, and evolutionary connections can be determined by assessing common DNA sequences.
• Humans and chimpanzees share around 98% DNA, whereas human-banana similarity is about 50%.

Mutations

• Mutations serve as indicators of evolution
• Divergence from a shared ancestor accumulates DNA mutations, with the difference in mutations revealing how long ago species diverged.
• Neutral mutations, which neither harm nor benefit, accumulate steadily and indicate divergence times between species, acting as a molecular timestamp.

Amino Acids

• Amino acid sequences in proteins are influenced by DNA instructions.
• Comparing amino acid sequences in proteins reveals evolutionary lineages.
• Hemoglobin, responsible for oxygen transport, shows remarkable amino acid sequence similarity in vertebrates.

Functional Relevance

• Conserved Sequences: Sequences crucial for protein function tend to remain consistent across species, indicating a common origin.
• Variability in Non-Essential Sequences: Changes in segments not critical for function can trace an organism's evolutionary trajectory.

Sequence Data and Evolution

• Sequence data reshaped the understanding of evolution beyond being just intriguing information.

Phylogenetic trees and Evidences

• Sequence data is used to build phylogenetic trees that visually represent evolutionary relationships and make evolutionary distances clear.
• Sequence data supports evidence from fossils and anatomy, such as similar gene sequences for hearing in bats and dolphins which supports echolocation evolution in both.

Superseding Morphological observations

• Organisms with no morphological resemblance may have similar DNA, while species with similar morphology may have different DNA due to convergent evolution.

Challenges in Using Sequence Data

• The Enigma of Convergent Evolution: Distinct species may evolve similar solutions, creating similar DNA or protein sequences that are not due to shared ancestry.
• Variable evolutionary rates: Evolution occurs at varying rates; some DNA segments evolve slowly, while others change rapidly.
• Genes can transfer directly between microorganisms, confusing evolutionary relationships

Interpretation of Sequence Data

• Sequence data is a valuable tool in evolutionary biology that needs careful interpretation and needs to be combined with other kinds of evidence.

Selective Breeding

• Variation exists between domesticated animal breeds and crop varieties.
• Selective breeding in cattle has led to breeds for egg-laying efficiency and ornamental purposes.
• Aesthetic preferences have shaped horse breeds evident in old photographs and paintings, with differences in facial structure, leg proportions, and physique

Agriculture and Beginnings

• Agriculture's genesis is linked to understanding selective breeding to support human settlements.
• The transformation from teosinte to maize shows selection refined features, creating a staple crop through generations.
• The wild mustard plant is the progenitor of broccoli, Brussels sprouts, and kale, with unique variants developed via emphasis on specific plant parts.

Archaeological Evidence

• Excavations show proof of ancestors' agricultural skills.
• Seed fossils show ancient grains were smaller than current ones, where selection led to larger yields.
• Ancient legume seeds, such as lentils and chickpeas, were also smaller, which shows selective breeding history.

Selective Seed Modifications

• Modern selective breeding aligns with today's requirements, with modified seeds for food.
• Disease resistance: Newer crop varieties are engineered to resist pathogens, securing yields and food security.
• Shelf-life and transportability: Crops like tomatoes have been bred to be robust for transportation.
• Nutrient content: Selective breeding increases the nutritional content of crops.

Selective Breeding benefits

• Selective breeding shows evolution's malleability and offers insight into evolutionary ideas.
• It shows that rapid shifts can occur with pressure, showing how changes emerge quickly.
• It epitomizes directional selection, like how humans shape domesticated species like environmental pressures mould species.

Genetic Diversity issues

• As specific traits becomes predominant with selective breeding, genetic diversity declines, causing vulnerability to environmental threats.
• Selective breeding support the foundational theory of evolution, as structures are seen across species, which indicates ancestors of those seen today.

Homologous Structures

• Homologous structures are anatomical across species, tracing back to a common origin, regardless of function, showing evolution from the same ancestral form.
• Definition: Homologous structures share evolutionary origins, where different functions can still be homologous.
• The term 'homologous' has Greek roots 'homos' for 'same' and 'logous' for 'relation', underpinning structures that share evolutionary history.
• Ancestral roots take priority: Morphologically similar homologous structures may have varying functionality for different species, however the ancestral origins are key.

Pentadactyl Limbs

• The pentadactyl limb is an example of homology.
• Origins and Evolution: The pentadactyl limb evolved from fish and adapted to different environments and lifestyles.
• In humans, the arm consists of the humerus, radius, ulna, carpals, metacarpals, and phalanges.
• Whales: Their bone structure mirrors the pentadactyl design, adapting for swimming but the humerus, radius, and ulna persists.
• Bats: Wings have a pentadactyl pattern, with elongated fingers and discernible humerus, radius, ulna, and phalanges, in the bones.

Flight

• Birds: While tailored for flight, avian wings still show the pentadactyl structure with adaptations for aerial mobility.

Homologous Structures found in Natural World

• Vertebrate Skeletons: Vertebrates share skeletal frameworks with an unchanged spinal column and ribcage.
• Floral Structures in Plants: Angiosperm floral parts show patterns hinting at shared origins.
• Eye Structures: Eye similarities span diverse organisms while varying in complexity and function

Evolutionary Significance

• Homologous structures show common ancestry among species, such as the pentadactyl limb in vertebrates.
• They trace evolutionary pathways, showing how species diverged from common ancestors through environmental adaptation. Darwin referenced homologous structures to strengthen his evolution theory, indicating species adapt and evolve

Developmental Studies

• Studying the embryonic development of homologous structures provides insight to evolutionary history.
• Unrelated species can evolve similar adaptations because of environment stresses, showing creative potential of natural selection
• Definition of Convergent Evolution: Convergent Evolution are unrelated organisms that independently evolve similar traits to survive in environment /ecological niches

Importance of Processes

• Its significance underscores adaptivity, where species arrive at similar solutions.
• It proves consistency of natural selection across species environments .

Bats and Birds

• Wings in Bats and Birds: Though different, bats and birds evolved wings, enabling them to fly.
• Bird Wings: Avian species modified feathered forelimbs where light bones and strong muscles aided flight.
• Bat Wings: Webbed hands with extended finger bones power flight which also serves thermoregulatory aspects.
• Differences underscore evolutionary benefits of flight for travelling and escaping predators.

Prickly spines

• Cacti and euphorbias show spiny exteriors to adapt.
• Cacti: Being located in the Americas, cacti store water in stems, and sharp spines deter herbivores.
• Euphorbias: With an ancestral homeland in Africa, euphorbias evolved spiny adaptions, warding off herbivore and thriving in conditions.
• Prickly adaptation reduces water loss by defending plants.

Sharks and Dolphins

• Dolphins and sharks streamlined bodies, where distinct forms emerged through aquatic bodies.
• Streamlined bodies with dorsal fins providing stability and vertical moving tails is for swimming.
• Shark Body: Ancient, fin ned forms adapted to moving fins. where bodies allow swimmers/hunters to move adeptly.
• Apex bodies due due to evolutionary fine tuning.

Eyes and Camoflage

• Compound eyes in insects /crustracians show marvels in viewing their surroundings .
• These eye detect light /slight movements , enabling evade capture.
• Crab and lobester eyes assist is spotting predators/ relocating food.
• Camoflauge provides nature for the creatures. -Leaf taild geckos show almost perfect hide by blending. -Stick Insect show nearly invisible features. S-nowy owls ad arctic fox sport white for hunting. These species help organism sustain over time

Mimicry and Toxins

• Mimicry shows cover gent by mimicing others, gaining protection -Harmless cover by gainong predatro/ toxins
• Some organism show a resistence to predators

Speciation of Origin

• Students must understand that speciation comes from the way that the species had been
• students must realise that spectation increase over time
• Spectation alludes on new species ,rooted on principle

New Species

• Specification shows a evolution is a result
• It it requres that spiece must isolate others to diverge
• Catalysts for divergence varries encompass -reproductive/ environmental processes for the specific species survival

Isolations

-To instigate species,specie need to be geographically isolAted -barriers are Mountains .

• population may need to in the eco system, and adapt to reproduce in another behaviour that they recognise
• Genetic Divergence
• population isolation that arries genetic variations

Gradual Change

-Evolutionry process of genetic shifts of a population at diffrent point

• propelled traits
• species remain consistent even when changes do happen

Distinctions of Genetics

• Transformation of linear history -New species emerge
• Genetic are foundational to production

Timeframe

• Evotion happen at shorts spans where species undergo naturally Spectation -Species take place gradually These are the mechcanisms leading to spectation

Geographic Isoation

Population become isolatated

Reporoductive isolation

Species in the same places need to be

• Tempotal Isolation is for mating
• Behaviuoral Isolation is based on calls Gametical Isolation occurs due to unsuccessful interaction

Genetic Shift

• Organism need to be have different functions For exampke fish speciation requires difffrent function 4r survival
• Genetics happen and speciation occura

Prezygotic Barriers

Mating and reproduction dont occur between populations at that stage

Barriers

-Organisms are avtive are reopduvrive at diffrent periods -One organsim live and other die

• Animals call/unique actractins

Post Zygotic barriers

• Happend after eggs had occur in the spern

Hybrid Sterillity(

Hybrid inviasbilty doesnt develop

• Hybred grow /cant reprodue

Sterility

Happens on specific times with offspring may or may no be able to have Some hybrixds may be sterile, but it means their pools are not able to connect

Reproduction

• Adaptive radiation allows closely related species to coexist without competing, thereby increasing biodiversity in ecosystems where there are vacant niches. Adaptive radiation is a pivotal evolutionary concept, playing a crucial role in shaping biodiversity. This study note will delve deeply into adaptive radiation, examining its mechanisms, driving forces, real-world examples, and overall impact on biodiversity Adaptive radiation Genetic These aee a range of the species to show how organisms change through the enivronment .where species can diverge overtime

• genetic allotypes

Adaptarions/Changes on Earth

Adaptive / genetic can alloptypes has been for speciation .Where things that can survive become better overtime. With formation and advatgaes as survival of the fittest , organism grow over time. They change to the enviomrnt to over come /adapt to the eco syste. Which results with adaptive/evoltutionty events are present. The world and space in all .

Allopatrics/ Apple

A apple magor flies may allude, for reproduction ,and adapt over time to survive on this new found form. • Over time, the two groups showed a mating preference for flies from the same tree type,• leading to reproductive isolation and ongoing speciation. Definition

• Barrier is needed at to take away . Geneitc Diverergence/ Reporductive
• These speciation must happen inorder for adaptartions to occut. • With no gene flow between them, species on the Atlantic and Pacific sides evolved distinctively, resulting in numerous species that can be found only on one side or the other.

Compations

• sympatric is the region location during geographical shift
• geneitc shuffles happen over time

Factors

• Population SizeIn smaller populations, genetic drift can have pronounced effects, potentially accelerating speciation. • Migration RateHigh migration between populations can inhibit speciation, as it maintains genetic homogeneity. • Environmental VariabilityThe more diverse the environmental challenges faced by separated populations, the quicker • they might adapt and diverge, promoting speciation.  Speciation Where adaption/evoltution happens at a steady rate

Evoltuiton

• Rapid SpeciationThis process is marked by the swift emergence of new species. Suchquick speciation frequently happens when apreviously unoccupied niche ore nvironmentbecomes available. • Diverse Niche OccupationAs various species evolve via adaptive radiation, they adapt to specific ecological roles, known as niches. This often results in distinctive physical orbehaviouraltraits among the descendant species, setting each apart from the others.

Drives

Factors • Colonisation of New Areas: An organism moving to a new area with few competitors might diversify to exploit available resources. • Evolutionary Innovations: Sometimes, new adaptations or behaviours allow organisms to exploit previously inaccessible resources. Such evolutionary breakthroughs can spur adaptive radiation. • Morphological,Physiological

• Behaviour

Examples

• the change of time All the adaptions needed happen

Hybrid /Gene

• Change by time With adaptions, there are limitations to make something function

Traits/Hybridisation

Barriers to hybridization and sterility of interspecific hybrids as mechanisms for ofpreventing the mixing of alleles between species • This occurs over time with offsprings/species

Timeframes on earth

All organisms can make it through there life cycles. It is is to ensure to prioritise the health +well being ,for organisms .This allows a chance for the animal to remain in the cycle of life longer and over time

• Selectice is with specific changes
• Changes cannot hapoen for it there are genes. With the environmemtn ,we can determine adaptions

Plant / Hybridization

These are some form or types of reproduction. Whery some plants create reproduction for the future or some just over time can not ,we can understand life. There are diffrent aspects for this where , we can view plant and species for earth itself through it all

Mechabnism/Hybrid/Steril

This all for nature to take over. With time and space for reproduction .Nature will find it own way with plants as well.

Diversity

• genetic in the species
• Over the process, we understand the different speication that come together /apart in new found knowledge for earth for organismm through earth itselfs
• With this hybrid/ genetic are in action to see the changes that occur
• Over space+Time*