Biology Unit 3 Flashcards

Questions and Answers

How does a cladogram show relationships between multiple organisms?

A cladogram shows relationships between multiple organisms by showing what each organism has in common with others and finding the common ancestor.

What is anatomical homology? Give 2 examples.

Anatomical homology is a similarity in structures and bones of species due to common ancestry. Examples include the one, two, many bone structures in several mammals and hand bones in monkeys and humans.

What information does the fossil record provide regarding organisms?

The fossil record can provide evidence of common ancestry in organisms by looking at bone structures and comparing them between organisms.

How does the study of embryology provide evidence for how organisms are related?

Embryology provides evidence for how organisms are related because it shows how organisms are similar during early developmental stages. Signup and view all the answers

What is molecular homology?

Molecular homology is the similarities in species DNA, RNA, and proteins. Signup and view all the answers

What similarities can you find in organisms that show that they are related?

Similarities that are able to be found in organisms that show they are related are similar bone structures, similar embryos, and similar DNA patterns. Signup and view all the answers

What is a cladogram?

A cladogram is a diagram that shows the relationships between organisms and their ancestors. Signup and view all the answers

How can a cladogram help scientists determine common ancestry?

A cladogram could help scientists see what happened throughout evolution to change populations over time and what organisms evolved from in the past. Signup and view all the answers

What are some drawbacks of using cladograms?

Drawbacks may include difficulties if the organisms are very different and don't have similarities to compare, missing links in ancestry, and not being specific enough. Signup and view all the answers

What is a homologous structure? Give some examples.

A homologous structure is a similar structure in a group of organisms caused by a common ancestor. Examples include the similar forelimb structure in mammals. Signup and view all the answers

Explain how the similarities in early embryonic development may point to common ancestry.

The similarities in early embryonic development point to common ancestry because they all have the same anatomical structures during their stage one embryo form. Signup and view all the answers

What are developmental homologies and how are they studied?

Developmental homologies are the similarities between animals during the early embryo stages, studied by looking at the similarities in embryo formations. Signup and view all the answers

What is a chordate, and what do all chordates have in common at some stage of development?

Chordates are a category of animals who are mostly vertebrates. All chordates have a notochord, dorsal hollow nerve cord, postanal tail, and pharyngeal slits at some stage of development. Signup and view all the answers

Why are organisms with similar genetic sequences also likely to have similar protein configurations?

Organisms with similar genetic sequences are likely to have similar protein configurations because they will have the same DNA and RNA to form the proteins. Signup and view all the answers

Define interdependence.

Interdependence is when the species depends on the environment and the other organisms around them. Signup and view all the answers

Identify the three types of advantages that can help organisms survive.

The three advantages that help organisms survive are morphological, physiological, and behavioral. Signup and view all the answers

Is the outcome of environmental changes for an organism always positive? Explain.

No, it is not always positive because some environmental changes will affect where populations live and if they survive. Signup and view all the answers

What have people done to help crows and barred owls?

People have planted many trees in the great plains that have helped crows and barred owls. Signup and view all the answers

What is adaptation and what does it lead to?

Adaptation is the selective pressures that affect the species' survival and reproductive rates, leading to organisms better suited for their environment. Signup and view all the answers

What is divergent evolution?

Divergent evolution is when new species diverge, or separate, from previous species. Signup and view all the answers

What are three initiators of divergent evolution?

Three initiators of divergent evolution are overcoming competition, adapting to niches, and neutral evolution. Signup and view all the answers

What is convergent evolution? Give some examples.

Convergent evolution is when species have similar traits but do not have common ancestors. Examples include the hooves of horses and cows. Signup and view all the answers

What is speciation? Name and describe 2 main causes of speciation.

Speciation occurs when populations are separated (geographical isolation) and occurs when no specific extrinsic barrier gene flow (reproductive isolation). Signup and view all the answers

When does extinction occur? What percent of once living things are now extinct?

Extinction occurs when many organisms in a species continually die off, and 99.9% of all once living things are now extinct. Signup and view all the answers

What is a causal relationship? Give an example.

A causal relationship is when the environmental change caused the change in the species. An example is how sediment in lakes affects the fish and organisms living there. Signup and view all the answers

What are the four factors of evolution?

(1) The potential for a species to increase in number, (2) the heritable genetic variation of individuals in a species due to mutation and sexual reproduction, (3) competition for limited resources, and (4) the proliferation of those organisms that are better able to survive and reproduce in the environment. Signup and view all the answers

Study Notes

Cladograms and Relationships

Cladograms illustrate relationships between organisms by depicting shared traits and identifying common ancestors.
A cladogram can reveal evolutionary changes over time, aiding scientists in understanding lineage and trait inheritance.

Anatomical and Molecular Homology

Anatomical homology is characterized by structural similarities among species, indicating common ancestry, e.g., bone structures in mammals.
Molecular homology refers to similarities in DNA, RNA, and proteins that further confirm genetic relationships across species.

Fossil Record and Evidence of Ancestry

The fossil record provides insight into common ancestry through the analysis of bone structures across different extinct and extant species.

Embryological Evidence

Embryology shows similarities in early developmental stages among organisms, suggesting evolutionary connections through common anatomical features.

Developmental Homologies

Developmental homologies involve similarities in embryonic development, highlighted by features such as gill slits and hollow nerve cords in early-stage embryos.

Characteristics of Chordates

Chordates, primarily vertebrates, share common features during development, including the notochord and dorsal hollow nerve cord.

Adaptation and Survival Advantages

Adaptation encompasses changes driven by selective pressures, leading to better survival in specific environments.
Advantages aiding survival include morphological, physiological, and behavioral traits that enhance fitness.

Evolutionary Processes

Divergent evolution results in new species arising from a common ancestor, often initiated by competition and adaptation to new niches.
Convergent evolution occurs when unrelated species develop similar traits, such as the hooves of horses and cows.

Speciation and Isolation

Speciation can result from geographical isolation or reproductive isolation, leading to the emergence of new species due to genetic divergence.

Extinction and Endangerment

Extinction is the end of a species, with 99.9% of all species that ever existed now extinct, often due to environmental shifts like sea-level drops.
An organism is deemed "endangered" when its population falls below sustainable levels.

Relationship Dynamics

A causal relationship implies that an environmental change directly affects species, while a correlational relationship indicates non-directly related changes.

Factors Influencing Evolution

The four key factors of evolution include potential population increase, heritable genetic variation, competition for resources, and the survival of the fittest leading to increased reproduction.

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Description

Test your knowledge of key concepts in Biology Unit 3 with these flashcards. Focused on cladograms and anatomical homology, this quiz will help you understand the relationships between organisms and the evidence provided by anatomical similarities. Perfect for students preparing for exams!