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TRANSCRIPT
Natural Selection & Common Ancestry
Speciation L.8.4B.3, Anatomical Structures L.8.4B.4
Performance Objectives:
· L.8.4B.3 Obtain and evaluate scientific information to explain that separated populations, that remain separated, can evolve through mutations to become a new species (speciation).
Evolution
· The gradual ___________ in a species over time due to ___________ in frequency of alleles in the gene pool of a population
· New alleles enter the gene pool as a result of ___________
· The changes eventually leads to a ___________ species forming that can no longer produce fertile offspring with the original specie population
HOW CAN NATURE HELP DRIVE EVOLUTION?
Speciation
· ___________ occurs when populations of the same species evolve to become so different genetically that they can ______ longer breed with one another to produce fertile offspring
· Takes place over many years
· Speciation most often occurs due to reproductive _______ of species that causes a change in the gene pool
· Isolation can occur when a population becomes ___________ due to geographic ___________ preventing them from mating
· Isolation can occur ___________ a population when the ___________ of a population keeps them from mating
Speciation due to Geographic Barriers
· ___________ Isolation occurs when populations become ___________ by physical barriers that keep them from mating
Give one reason the salamanders are so different.
· Rivers, Mountains, Islands
Speciation within a Population
· Ecological isolation occurs when species live in the same region but occupy different habitats so they ___________ encounter each other
· Example: Lion lives in the grasslands & tigers live in the rainforest
· Behavioral isolation occurs when ___________ behavior patterns & rituals isolate the species for mating
· Courtship behaviors/___________ calls
· Habitat *nocturnal
Speciation of Darwin’s Finches
· Darwin’s Finches experiences ___________ due geographic isolation
HOW LIVING & FOSSIL REMAINS SUPPORT THAT SPECIES COULD HAVE COMMON ANCESTORS
Performance Objectives:
· L.8.4B.4 Analyze displays of pictorial data to compare and contrast embryological and homologous/analogous structures across multiple species to identify evolutionary relationships.
Biological ___________ of Evolution
· Comparative Anatomy
· Embryological Structures
· Vestigial Structures
· Fossil Record in strata
Similarities in Body Structure
Comparative Anatomy is the study of similarities and differences among structures of living species.
· Similarities in Body Structure: Homologous Structures
· ___________ Structures are body parts of organisms that are ___________ in structure and position but different in function
· Used as evidence to support that the species may have more recent ___________ in ___________
· Example: Bird wing and a Whale fin have same bone structure pattern, but each animal use the limbs for different purposes
· Differences in Body Structure: Analogous Structures
· ___________ Structures are body parts that perform a similar function, but have developed from different internal ___________.
· Used as evidence to support that the species do ___________ have recent ancestors in common
· Example: Bird wing and an insect wing are both used for ___________ but each wing is made of different types of tissue that builds the wing
· Similarities in Early Development: Embryological Structures
· ___________ is the study of the development of embryos from fertilization to birth.
· Scientists look at embryos of different organisms and find that many embryos ___________ one another.
· The more similarities the more ___________ ancestors
· Example: fish and salamander may have more common ancestors than the rabbit and the turtle
· Vestigial Structures are structures found in an organism that have ____their original function through evolution
· Example: Whales possess a femur and pelvis, but these bones are ____ ___________ useful to the mammals.
Fossil Record in the Strata (rock layers)
· Fossils from organisms that died longer ago are buried ___________ in the sediment/rock than fossils from organisms that died more recently.
· Fossil ___________ show evidence to support that species have ___________ changed over long periods of time.
· Example: ___________ of ancestor species of a horse