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