Evolution

What is adaptation?

A trait that helps an organism survive and reproduce

morphological species concept

characterizes a species by body shape and other structural features

Earth's early atmosphere did not contain what?

oxygen

biological evolution

the change over time in populations of related organisms and their traits

sex

the biological distinction between females and males

Multicellular organisms

an organism that is made up of many cells

stabilizing selection

form of natural selection in which individuals near the center of a distribution curve have higher fitness than individuals at either end of the curve

geographic isolation

isolation between populations due to physical barriers

What can cause mutations?

- missed repairs - UV radiation/chemicals

Evidence of Evolution

1) Fossil Record 2) Embryology 3) Homologous Structures 4) DNA 5) Vestigial Structures

Rates of Speciation

1. Gradualism 2. Punctuated Equilibrium

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

radioactive dating

A technique used to determine the actual age of a fossil on the basis of the amount of a radioactive element it contains

What is melanin?

A protein pigment found in epidermal cells, protect skin against radiation from the sun.

what is the difference between evolution and Biological evolution

Biological evolution is change of traits over time and evolution Is change over time not traits.

How has racial classification been used in North America?

By races; In North America, people usually think in terms of Black, White, Asian, Hispanic or Latino, and Indian or Native American.

Evolution

Change over time

Based on the risk factors discussed in the film, which of the following groups should consider taking vitamin D supplements to avoid rickets?

Children born to parents with dark skin living far from the equator.

fossil record

Chronological collection of life's remains in sedimentary rock layers

Besides genetics, what other factors can affect a person's appearance and growth?

Environment influencers

What is macroevolution?

Evolutionary changes that result in the formation of new species.

What is speciation?

Formation of new species

What two main factors is evolution dependent on?

Genetic mutations and natural selection

How does natural selection lead to evolution?

Helpful traits accumulate among surviving members of the species.

What is fitness, evolutionarily speaking?

How good a genotype can produce offspring

variation in human skin color

Human skin color variation is primarily determined by the type and amount of melanin pigment in the skin. Also, The variation in human skin color correlates with the intensity of UV radiation around the world.

spontaneous generation

Hypothesis stating that life could arise from nonliving matter.

list 3 sources of genetic variation

Mutations, gene flow, and sex

directional selection

Natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals.

examples of instances in which evolution has been observed

New species developing, and diseases

What are examples of sexual selection?

Peacock feathers, dances, gifts

Co-evolution

Process by which two species evolve in response to changes in each other

convergent evolution

Process by which unrelated organisms independently evolve similarities when adapting to similar environments

Pasteur's experiment

Published results of his experiment. Placed sterilized broth in a sterilized flask. He clearly showed that bacteria couldn't arise spontaneously. Only when open to air, the bacteria could emerge.

reproductive isolation

Separation of species or populations so that they cannot interbreed and produce fertile offspring

What are some traits that people share?

Skin and hair color, facial characteristics, body shape, and stature.

What evidence supports the vitamin D hypothesis for the evolution of lighter skin tones?

Some indigenous peoples living at high latitudes have darker skin, but they tend to eat foods rich in vitamin D.

biological species concept

Species is a group of populations whose members have the potential to produce fertile offspring.

Evolution in natural communities arises from both constraints and opportunities. What are the constraints?

The constraints come from competitors, primary among the same species

Darker skin is more prevalent in high-UV areas. Dr. Jablonski proposed a hypothesis to explain the selective pressure for darker skin in these environments. On what evidence did she base this hypothesis?

The larger amount of brown-black melanin in darkly pigmented skin protects circulating folate from being destroyed by UV radiation.

Why isn't skin color a good way to classify people?

They are essentially labels of ethnicity that are used for categorizing and discriminating.

What are transitional forms?

They are forms of species intermediate between the orginal form and the current form.

Why do sub-Saharan Africans have the same dark skin color as many people in places like southern Asia and Australia?

They continue well outside of the geographic areas in which a "race" is stereotypically supposed to exist.

How does melanin affect the color of the skin?

UV exposure darkens existing melanin and stimulates melanocytes. When melanocytes are stimulated, melanin is transferred from the melanocytes to keratinocytes in the stratum Basale.

Examples of homologies

Wing of bird, flipper of dolphin

What is a species?

a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding.

molecular species concept

a group of organisms are classified in the same species if they appear identical in DNA sequences

Theroy

a logical explanation for events that occur in nature

Melanocytes

a mature melanin-forming cell, typically in the skin.

examples of vestigial structures

appendix, tailbone, wisdom teeth, 3rd eyelid

In which of the following areas of the globe would you expect to find relatively high amounts of UV radiation?

areas at high elevation and areas at a latitude near the equator.

Isolating mechanisms

barriers to imitation that prevent rivals from competing away the advantage a firm may enjoy

limitations of biological species concept

cannot be applied to fossils or asexual organisms, emphasizes absence of gene flow

Pheomelanin

causes the reddish browns of freckles and red hair.

Mutation

change in a DNA sequence that affects genetic information

What is the relationship between Humans and Apes?

common ancestors

Are dark-skinned people at an advantage or disadvantage in northern latitudes?

disadvantage because there is not enough vitamin D

descent with modification

each living species has descended, with changes, from other species over time

divergent evolution

evolution of one or more closely related species into different species; resulting from adaptations to different environmental conditions

What is microevolution?

evolutionary change within a species or small group of organisms, especially over a short period.

limitations of biological species concept

extinct organisms and organisms that don't reproduce sexually

Causes of speciation

geographic isolation, reduction of gene flow, reproductive isolation

Eumelanin

gives rise to a range of brown skin tones, as well as black, brown, and blond hair, and pheomelanin.

UV light

invisible light that lies beyond violet. Has higher energy and shorter wavelengths than visible light does.

how does melanin respond to ultraviolet radiation?

it reacts less than 1 out of every 1000 times it becomes excited. This allows melanin to protect more sensitive molecules, like DNA, from UV exposure.

gene flow

movement of alleles from one population to another

disruptive selection

natural selection in which individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle of the curve

Did Darwin recant evolution on his deathbed?

no

Did humans evolve from apes?

no

do maggots' appear out of nothing?

no

Prokaryote cell

no nucleus, no organelles, DNA floating around, genetic material, cell membrane, cytoplasm, simple

Homologies

phenotypic and genetic similarities due to shared ancestry

What is coevolution?

process in which two or more species evolve in response to changes in each other

what were most likely the first type of cells?

prokaryotes

vestigial structures

remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species.

How does selection actually work?

selection can only work on genetic variation that already present in any new generation, and genetic variation occurs randomly, not in the response to the needs of the population or organism

What is artificial selection?

selective breeding of plants and animals to promote the occurrence of desirable traits in offspring

homologous structures

similar structures that related species have inherited from a common ancestor

Law

something backed up by a mathematical statement

Embryology

study of embryos and their development

Besides melanoma, what other conditions does melanin shield against?

sunburn damage and damage to DNA

Modification by Natural Selection

the idea that the environment selects individuals best suited to live there for survival

Epigenetics

the study of environmental influences on gene expression that occur without a DNA change

how does light interacts with the pigments in a red tomato?

the pigments reflect red light

how does epigenetics apply to evolution?

the quality of life directly affects how our genes operate. diseases can have started all the way back into you ancestry. it's not just a health problem but a much broader social equity issue.

natrual selection

the theory that organisms better suited to their environment are more likely to survive

sexual selection

when individuals select mates based on heritable traits