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Analogous and Vestigial Structures

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Analogous and Vestigial Structures Write in complete sentences! Don t talk during the Catalyst! Catalyst Cougars eat Bucaneers, which have decreased in population ... – PowerPoint PPT presentation

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Title: Analogous and Vestigial Structures


1
Analogous and Vestigial Structures
Write in complete sentences! Dont talk during
the Catalyst!
  • Catalyst
  • Cougars eat Bucaneers, which have decreased in
    population over the past few years. What is the
    environmental pressure?
  • Humans and cows both have hearts with four
    chambers.
  • What type of structure is this?
  • Describe what it tells us about how humans and
    cows evolved.
  • What are two things ALL animal embryos have in
    common? What does this tell us about how animals
    evolved?

2
Objectives
  • By the end of today, all SWBAT
  • Explain how analogous structures support the
    theory of evolution
  • Explain how vestigial structures support the
    theory of evolution

3
Agenda
  • Review
  • Structures
  • Analogous
  • Vestigial
  • Guided Practice
  • Independent Practice/Homework
  • Closing
  • Exit Questions

4
Catalyst Review
  • Cougars eat Bucaneers, which have decreased in
    population over the past few years. What is the
    environmental pressure?
  • The environmental pressure is the decrease in
    population of the Bucaneers.
  • WHY?

5
Catalyst Review
  • Humans and cows both have hearts with four
    chambers. What type of structure is this, and
    what does it tell us about how humans and cows
    evolved?
  • Human and cow hearts are homologous structures.
  • This shows that humans and cows evolved from a
    common ancestor with a four-chambered heart.

6
Catalyst Review
  • What are two things all animal embryos have in
    common? What does this tell us about how animals
    evolved?
  • All animal embryos have gill slits and tails.
  • This is evidence that all animals evolved from
    the same common ancestor.

7
Homework Review
  1. What are homologous structures? Provide two
    examples of homologous structures.
  2. What is an embryo?
  3. What is a common ancestor? Give an example.
  4. All animal embryos start off looking very
    _______________. For example, they all have
    _______________ and _______________. These traits
    are examples of _______________ structures.

8
Homework Review
  • Lions and tigers have similarly structured tails.
    What type of structures are these? EXPLAIN how
    these structures support the theory of evolution.
    (Hint use the phrases evolve and common
    ancestor!)
  • How can we use the appearance of cat and horse
    embryos to support the theory of evolution?
    (Hint use the phrases evolve and common
    ancestor!)

9
Comparative Anatomy
  • Scientists can compare the anatomy of different
    organisms to figure out how closely they are
    related.
  • Anatomy body structure

10
Analogous Structures
  • Analogous structure Parts of different species
    that have the same function, but EVOLVED
    SEPARATELY
  • Key Point 1 Analogous structures show that
    unrelated species will evolve similar
    adaptations in response to similar environmental
    pressures
  • Natural selection selects for (keeps around)
    mutations that increase fitness in the specific
    environment.
  • If organisms they live in similar environments,
    they will evolve similar structures.

11
Insect, bird, and bat wings evolved completely
separately. Unrelated organisms will evolve
similar adaptations in response to similar
environmental pressures!
  • No recent common ancestor!!!

12
Seals and penguins both have streamlined bodies,
and store fat to keep them warm in the cold
water. Unrelated organisms will evolve similar
adaptations in response to similar environmental
pressures!
13
Vestigial Structures
  • Vestigial structure Part of an organism that is
    no longer used for anything
  • Key Point 2 Vestigial structures show that a
    species used to live in a different environment.
  • Organism moved into a new environment, where the
    vestigial structure decreases fitness
  • No longer needed, waste of energy
  • Risk of disease

14
Letter c hind legs of a baleen whale skeleton
  • Vestigial no longer used!!!

15
Blind salamanders have eye sockets!?!?
16
So, what about me?
17
Guided Practice Notes Reflection
  • How do analogous structures provide evidence for
    evolution?
  • Analogous structures show that unrelated
    organisms will evolve similar adaptations in
    response to similar environmental pressures

ADD IT!!!
If you cant find the answer
18
Guided Practice Notes Reflection
  • How do vestigial structures provide evidence for
    evolution?
  • Vestigial structures show that the species used
    to live in a different environment
  • Organism moved into a new environment where the
    vestigial structure decreased fitness so it
    started to degrade

ADD IT!!!
If you cant find the answer
19
Study!
  • This practice will cover yesterdays lesson
    (homologous structures) as well as todays
    (analogous and vestigial structures).
  • Take three minutes to study your notes from
    yesterday and refresh your memory before we
    proceed.

20
Guided Practice (GP)
Are these structures (A) Homologous, (B)
Vestigial, (C) Analogous?
  • Human embryos and cat embryos both have gill
    slits.

HOMOLOGOUS
21
Guided Practice (GP)
Are these structures (A) Homologous, (B)
Vestigial, (C) Analogous?
  • Birds and insects both have wings, but they
    developed in completely different ways.

ANALOGOUS
22
Guided Practice (GP)
Is this structure (A) Homologous, (B) Vestigial,
(C) Analogous?
  • Snakes dont have legs, but they do have hip and
    leg bones.

VESTIGIAL
23
Guided Practice (GP)
Is this structure (A) Homologous, (B) Vestigial,
(C) Analogous?
  • The human appendix a small organ next to the
    intestines doesnt seem to do anything at all.

VESTIGIAL
24
Guided Practice (GP)
Are these structures (A) Homologous, (B)
Vestigial, (C) Analogous?
  • Cat embryos and human embryos both have tails.

HOMOLOGOUS
25
Guided Practice (GP)
Are these structures (A) Homologous, (B)
Vestigial, (C) Analogous?
  • Dolphins and sharks both have fins, but they
    evolved completely differently.

ANALOGOUS
26
Guided Practice (GP)
Are these structures (A) Homologous, (B)
Vestigial, (C) Analogous?
  • Alligators and bats have the same bone structure
    in their forelimbs (front legs for alligators,
    wings for bats).

HOMOLOGOUS
27
Guided Practice (GP)
Is this structure (A) Homologous, (B) Vestigial,
(C) Analogous?
  • Humans have wisdom teeth (third molars), even
    though they are not needed to chew up food.

VESTIGIAL
28
Guided Practice (GP)
Are these structures (A) Homologous, (B)
Vestigial, (C) Analogous?
  • Humans and squids both have eyes, but they
    evolved in completely different ways.

ANALOGOUS
29
Independent Practice (IP)
  • Get an early start on the homework.

30
Key Point Wrap-Up
  • Key Point 1 Analogous structures show that
    unrelated species will evolve similar
    adaptations in response to similar environmental
    pressures
  • Key Point 2 Vestigial structures show that a
    species used to live in a different environment.
  • Organism moved into a new environment, where the
    vestigial structure decreases fitness

31
Exit Question Choose one optionWrite in
complete sentences!
  • All humans have a tail bone, but we dont have
    tails.
  • What type of structure is this?
  • EXPLAIN how this structure provides evidence for
    evolution.
  • Dogs and alligators both have long snouts that
    allow their jaws to open wide. However, they
    evolved in completely different ways.
  • What type of structure is this?
  • EXPLAIN how these structures provide evidence for
    evolution.
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