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Body Structure

Body Structure

A part of an organism, for example, one or more bones

Fossil

Naturally preserved evidence of life

Limb

An organism’s arm, leg, or wing

Extinct

Having died out completely and no longer alive anywhere on Earth

Species

A group of organisms of the same kind that do not reproduce with organisms from any other group

Paleontologist

A person who studies fossils to understand the history of life on Earth

Generation

A group of individuals born and living at about the same time

Common Ancestor Population

An older population from which two or more newer species descended

What are body structures determined by?

The code of DNA and how it gets passed down through generations over many years

Shared Structure

When two species' body structures are made from bones that are in the same pattern and have a similar position in the body

Descendent Species

A more recent species that evolved from an ancestor population

Evolution

So many changes that the organism is a different species

Related

Sharing a common ancestor population

Inherit

To receive genes from a parent

Trait

A specific characteristic of an individual organism

Mutation

A random change to a gene that sometimes results in a new trait

Speciation

The process by which one population evolves into two or more different species

Stability

When something stays mostly the same over time

Environment

Everything biotic and abiotic that surrounds an organism

Natural Selection

The process by which the distribution of traits in a population changes over many generations

Adaptive Trait

Trait that makes it more likely that an individual will survive in a specific environment

1. What are ALL the observations paleontologists will use to identify a fossil in order?

1) Pay careful attention to body structures, especially how bones are grouped together 

Observe the size of bones within body structures

Observe the position of body structures

Observe the same fossil evidence several times to see what you’ve missed

Count the number of bones

Use observations of fossil evidence to make careful comparisons to other fossils and living species.

They use observations of fossil evidence to make careful comparisons to other fossils and living species

What do paleontologists do with the observations they make?

What two main types of evidence do Paleontologists use to determine common ancestors?

fossils and DNA

What’s the difference between a species and a population?

A species is one type of organism that doesn’t reproduce with any other species, but a population is a group of the same type of organism living in the same area

Do shared structures always have the same purpose?

No, they don’t. This is because if an organism has the same body structure as another, they might not all use it for the same thing. An example of this would be one organism could use their distal bones for swimming and another for running.

What did all living things evolve from?

All living things evolved from the same single-celled organism long ago

How long ago did the first living organism (a single cell) from which every other organism evolved from life?

4 billion years ago

How long ago did the first mammal, from which all other mammals including humans, evolved live?

65 million years ago

If an organism looks similar to another, does that mean they are related? Why or why not?

No, they could not be related if they look similar. This is because they would have to have a similar body structure, meaning they had a common ancestor at some point.

What are body structures determined by?

The code of DNA and how it gets passed down through generations over many years

 ___________________ in two very different species can be evidence that both species evolved from a common ancestor.

shared body structures

What are two things that all organisms would share (have in common) if they are related to each other?

cell structure and DNA

What is the definition of stability? Give an example

When something stays mostly the same over time.  Over 20 years, the distribution of the species only went down by 3

Evolution happens as a result of what?

speciation

What is the most common way that a population gets separated for speciation to occur?

When a barrier, such as a mountain range or body of water separates a population.

The process of speciation takes place __________ as adaptive mutations build on one another over many __________________.

slowly and generations

define evolutionary time

The very long time that spans the history of Earth, from the very first cellular life to the present

How long ago did evolutionary time start?

roughly 4 billion years ago

What is diagnostic structure

any structure that helps you identify an organism’s place on the evolutionary tree ( small things that help you pinpoint where the organism goes on the evolutionary tree )

Why does a descendent species have structures different from those of its ancestor?

Because environments change over time, the adaptions must change with it. The organism gets the adaptations from either the previous generation/s or develops it over time because it will help it survive in the environment.

Give at least 3 examples of diagnostic structures that can help classify an organism

Same nose, same ribcage, same tail

What is the definition of a physical adaptation? Give an example.

Any part of an organism’s biology that helps it survive in its environment. ( ex: the color of its fur, the thickness of its fur )

What is the definition of a behavioral adaptation? Give an example.

 An action an organism takes that helps it survive in its environment ( ex: birds migrating, ants in colonies )