Biology- Unit 3

What is a causal relationship? What is a correlational relationship? Give an example of causal relationship.

A causal relationship is when the environmental change caused the change in the species and a correlational relationship is when there was a change in the environment and species but they were not directly related. An example of a causal relationship is how sediment in lakes affects the fish and organisms living there.

How can a cladogram help scientists determine common ancestry? What are some benefits of this system?

A cladogram could help scientists see what happened throughout evolution to change populations overtime and what organisms now evolved from in the past. It can also show how traits were passed down.

What is a cladogram?

A cladogram is a diagram that shows the relationships between organisms and their ancestors.

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 a homologous structure? What are some examples?

A homologous structure is a similar structure in a group of organisms caused by a common ancestor. An example in mammals is the similar forelimb structure, one bone, two bones, and many bones. The African Elephants and Wooly Mammoths are similar because they have the same ancestors and structures but are different species.

What is adaptation? What does it lead to?

Adaptation is the selective pressures that affect the species survival and reproductive rates. Adaptation leads to producing organisms better suited for their environment.

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

Chordates is a category of animals who are mostly vertebrates (having a spinal cord). All chordates have a notochord, dorsal hollow nerve cord, postanal tail, and pharyngeal slits at some stage of development.

What is convergent evolution? What are some examples?

Convergent evolution is when species have similar traits but do not have common ancestors. Some examples are hooves of horses and cows and long tongues of anteaters and aardvarks.

What are developmental homologies and how are they studied?

Developmental homologies are the similarities between animals during the early embryo stages. They are studied by looking at the similarities in embryo formations.

What is divergent evolution? What are three initiators of divergent evolution? What is a niche?

Divergent evolution is when new species diverge, or separate, from previous species. Three initiators of divergent evolution are overcoming competition, adapting to niches, and neutral evolution. A niche is a position an organism has in the overall ecosystem it lives in.

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.

When does extinction occur? What percent of once all living things are extinct now? When did it happen? What caused it? When does an organism become "endangered"?

Extinction occurs when many organisms in a species continually die off. The percent of all once living things that have died is 99.9%. This happened about 439 million years ago due to a drop in sea levels. An organism becomes endangered when a species population number falls below acceptable limits.

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

Geographical isolation occurs when populations are separated and reproductive isolation happens when no specific extrinsic barrier gene flow.

Define interdependence

Interdependence is when the species depends on the environment and the other organisms around them.

What is molecular homology?

Molecular homology is the similarities in species DNA, RNA, and proteins.

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 or not. For example, deforestation would affect bird populations because they live and build nests in trees.

Why are organisms with similar genetic sequences also likely to have similar protein configurations? State at least one specific example of this.

Organisms with similar genetic sequences are also likely to have similar protein configurations because they will have the same DNA and RNA to form the proteins. One example is the Human and Chimpanzee compared to the Rhesus Monkey. There is only one difference in the protein sequences for those two categories.

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.

Answer the lesson question: 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.

What are some drawbacks of using cladograms?

Some draw backs may be if the organisms are very different and don't have similarities to compare, hard if you have missing links throughout ancestry, might not see all changes, can't see genetics, and not specific enough.

What information does the fossil record provide regarding organisms? How?

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

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.

What is anatomical homology? What evidence do anatomical homologies provide? Give 2 examples.

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

Explain how the similarities in early embryonic development may point to common ancestry among these animals. Make sure to state what they all have in common.

The similarities in the early embryonic development may point to common ancestry because they all have the same anatomical structures (gill slits, hollow nerve cord, and embryo shapes) during their stage one embryo form.

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

Three advantages that help organisms survive are morphological, physiological, and behavioral.